US3339115A - Directional relay apparatus - Google Patents

Description

Aug. 29, 1967 H. J. CALHOUN DIRECTIONAL RELAY APPARATUS 5 Sheets-Sheet 1 Filed May 17, 1965 -i E M w- 5 m 4 M R m n v H GE M II II I W E W as fifi4 m K M AR K I LCM m n m 4 4 E02 U 4 4 A TNT U R W E U 2 M m: E E TN. 2 $1 53mm i 6 8 FS 75 1 w M M Q m v. m m (I I. i O J a c 6 m a b g 6 r I fi m a w w W J M z 7E 2 6 5f 3 J L F FIGJA.

1967 H. J. CALHOUN 3,339,115

DIRECTIONAL RELAY APPARATUS Filed May 17, 1965 5 Sheets-Sheet 3 DIRECTIONAL RELAY APPARATUS Filed May 17, 1965 5 Sheets-Sheet 4 FIG-5A- Aug. 29, 1967 J. CALHOUN 3,339,115

DIRECTIONAL RELAY APPARATUS Filed May 17, 1965 5 Sheets-Sheet FIG.7A- a United States Patent )fiice 3,339,115 Patented Aug. 29, 1967 3,339,115 DIRECTIONAL RELAY APPARATUS Howard J. Calhoun, Millington, N.J., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 17, 1965, Ser. No. 456,209 29 Claims. (Cl. 317-36) This invention relates generally to relaying apparatus and more particularly to the type known as distance relays.

An object of this invention is to provide a relaying apparatus using static type circuit components.

A further object of this invention is to provide such an apparatus which has a minimum number of components.

A still further object of this invention is to provide 'a fault sensing network utilizing not more than two compensaters and which apparatus will respond to both line to line and three-phase faults.

A still further object of this invention is to provide a relaying network in which the phasing of single operating quantity with respect to one or the other of a pair of polarizing quantities is relied upon to provide a tripping signal upon the occurrence of a fault in the protected network.

Another object is to provide an improved trip controlling network which will remain ineffective as long as a predetermined one of three control signals lags the phase of the other two thereof but which will actuate the trip mechanism whenever this particular signal leads either or both of the other two signals.

Other objects of this invention will be apparent from the description, the appended claims and the drawings in which drawings:

FIGURE 1 Qcomlprising FIGS. 1A, 1B) shows a schematic diagram of a relaying apparatus embodying the invention.

FIG. 2 is a schematic diagram of the amplifying network for actuating the breaker trip coil.

FIG. 3 and 3A are vector diagrams illustrating a normal non-faulted network operation;

FIGS. 4 and 4A are vector diagrams illustrating a first type of line to line fault.

FIGS. 5 and 5A are vector diagrams showing a second type of line to line fault.

FIGS. 6 and 6A are vector third type of line to line fault; and,

FIGS. 7 and 7A are vector diagrams illustrating a three-phase fault.

Referring to the drawings by characters of reference, thenumber 1 indicates generally a three-phase power distribution network having abranch network 2 connectable and disconnectable from thenetwork 1 by means of a usual breaker 4 having a trip coil 6 operated by a trip coil amplifyingnetwork 8 shown in FIG. 2. The amplifyingnetwork 8 has at least one pair of input terminals and in the instant shown has three pairs thereof 10, 12 and 14 for connection to the output terminals of the trip coil actuatingnetworks 16, 18 and 20 of the three protection zones.

These trip coil actuatingnetworks 16, 18 and 20 are controlled respectively bydistance logic networks 22, 24 and 26 ofzones 1, 2 and 3 shown in FIGURE 1A. These distance logic networks are identical to each other except for certain adjustments which permit the magnitudes of the control quantities developed therein to be of different relative magnitudes with respect to the values of the current and voltage in thepower network 1 at the station location that the signals are derived. The voltage and current quantities may be sensed in the usual manner as by thetransformer arrays 28 and 30. The

diagrams illustrating a adjustment of thezone 1network 22 is such that the control quantities are large with respect to the line quantities whereby thenetwork 22 responds to faults which occur a first predetermined distance from the breaker 4.Zone 2 is adjusted to respond to faults occurring further beyond the breaker andzone 3 is adjusted to respond to faults still further beyond. Normally, in accordance with prior operating practice well known to those skilled in the art, the zones will be separated by the breakers and supplied with electrical energy from additional power sources, and similar as forexample to that discussed in Patent No. 2,873,460. Since thezone 2 andzone 3 actuating and logic networks are identical to thezone 1 networks a detailed description of only thezone 1 networks will be given.

Thepotential transformer array 28 comprises three transformers having their primary windings connected in Y to theconductors 32, 34 and 36 of thebranch network 2 and having the neutral terminal connected to ground. The secondary windings of thisarray 28 are Y connected to thecontrol busses 38, 40 and 42 and the neutral terminal is grounded. The potential derived electrical quantities appearing between theconductors 38, 40 and 42 are phased so that the vector quantities representing these quantities have the same relation with respect to each other as the vector quantities representing the voltages of thesupply conductors 32, 34 and 36 of thebranch network 2.

Thecurrent transformer array 30 comprises three Y connected current transformers associated with the threeconductors 32, 34 and 36 respectively and developing current derived quantities which are representative of the current flowing in thebranch network 2. These transformers energize individual currentquantity conducting conductors 44, 46 and 48. A commoncurrent quantity conductor 50 is connected to the neutral connection of thearray 30.

The distance logic networks comprise a fault operatesignal network 52, a line to line fault polarizingsignal network 54, and a three-phase fault polarizingsignal network 56 energized from the potential and current derived quantities supplied from the voltage andcurrent transformer arrays 28 and 30. The potential quantity is supplied to the fault operatesignal network 52 through atransformer 58 having a tapped primary winding 60 and energized from first and second potentialquantity input terminals 64 and 66 connected respectively to thebuses 38 and 40. By a suitable selection of the tap of the winding 60 the volts per turn of asecondary winding 62 may be determined and thereby the magnitude of the potential quantity supplied to thenetwork 52 relative to the potential between the conductors 32 and 34. The connection of theterminal 64 and the winding 60 forzone 1 is to tap a forzone 2 is to tap b and tozone 3 is to tap c as illustrated in my said patent to permit the use of the same distance logic network for each of thezones 1, 2 and 3. Thetransformer 58 may serve to isolate thenetwork 52 from the conductors or one terminal of the winding 62 may be connected as shown to an intermediate tap of the primary winding 60 to reduce the turns required by the winding 62. The other terminal of thewinding 62 is connected through the output winding 70 of acompensator 72 and a transientsupressing network 73 to the oneoutput control terminal 74 of a first pair of output terminals 74-76 of the distance logic net-work 22. Thesecond control terminal 76 of the first pair of output terminals is connected by aconductor 77 to acommon terminal 78 of the winding 60 oftransformer 58 and winding of a transformer 88 to complete the secondary circuit of thetransformer 58. The primary circuit is completed by connectingterminal 78 to theinput terminal 66.

If desired, atransient suppressing network 80 may be connected between theoutput terminal 76 and the common connection 81 of winding 70 to thetransient suppressing network 73.

Thecompensator 72 may be of the same type as the compensator T of my said patent. As such it may take the form of a transformer having a core with an air gap, sometimes known as a mutual inductance, and having compensatingwindings 82 and 84 inductively coupled by means of the core to the output winding 70. Thecompensator 72 vectorially adds the quantities applied to thewindings 82 and 84 to provide a current derived summed quantity for modifying the potential quantity supplied by thetransformer 58. This summed quantity is phase shifted an amount equal to the magnitude of the predetermined characteristic phase angle of thebranch network 2 by aphase shifting arrangement 86 whereby the compensating quantity applied to the output terminals of thewinding 70 is properly phased as will be described in greater detail below. Thecompensator 72 is a summing device which provides a compensating output quantity for addition to the potential derived quantity as may be represented by the vector V in any of FIGS. 3 through 7A. The phase shifting arrangement may take the conventional form of a resistor shunting a portion of the winding 70.

The line to line fault polarizingsignal network 54 is similar to the fault operatesignal network 52 and comprises the transformer 88 having the tappedwinding 90 and a secondary winding 92. The adjustable tap of the Winding 90 is connected to a third input terminal which is connected to the conductor 42. As stated above, the other terminal of thewinding 90 is connected to thecommon terminal 78 and to the second potentialquantity input terminal 66. Thewinding 90 is thereby energized from the third potential derived quantity. One end of the winding 92 is connected to a tap on the winding 90 and the other end thereof is connected through the output winding 94 of asecond compensator 96 and atransient suppressing network 104 to oneoutput control terminal 106 of a second pair of output terminals 7 6106 ofnetwork 22. Thesecond compensator 96 like thecompensator 72 is provided with compensatingwindings 98 and 100 and aphase shifting arrangement 102. The first control terminal of this second pair of control terminals is common with thesecond control terminals 76 of the first pair of control terminals, and connects with thecommon terminal 78. Atransient suppressing network 105 may be connected between theterminal 76 and the connection between thenetwork 104 and the winding 94.

In order to provide the desired output of compensating quantities of thecompensators 72 and 96, certain of the current derived quantities provided by thecurrent transformer array 30 are caused to fiow through thecompensating windings 82, 84, 98 and 100 as indicated by the vector diagrams. More specifically,windings 84 of compensation of thelogic networks 22, 24 and 26 are connected in series with each other and with theconductor 44 to thecommon conductor 50. Thewindings 82 and 100 of the compensators of the logic networks are connected in series with each other withcurrent conductor 46 to thecommon conductor 50. Similarly thewindings 98 of the logic network are connected in series with each other and theconductor 48 to thecommon conductor 50. The direction of the current quantities through the compensatingwindings 82 and 84 of thecompensator 72 is such that the vector V representing the quantity of the output terminal of the winding 70 is the vector sum of the positive vector I which represents the current derived quantity that is proportional to the magnitude of the current in the conductor 32 and the negative vector -I which represents the current derived quantity that is proportional to the current in the conductor 34, and phase shifted by an amount determined by thenetwork 86. Similarly the directions of the current derived quantities through thewindings 98 and 100 of thecompensator 96 is such that vector V representing the quantity of the output terminals of the winding 94 is the vector sum of the positive vector L; which represents the current derived quantity that is proportional to the current in theconductor 36 and the negative vector I which represents the current derived quantity that represents the current in the conductor 34 and phase shifted as determined by thenetwork 102. This arrangement, with the phasing provided by thearrangements 86 and 102 is vectorially illustrated under non-fault conditions by the vector diagram of FIG. 3. The phase shift imparted by thephase shifting arrangements 86 and 102 is preferably the impedance angle of thebranch network 2. The phase shifting apparatus adds vector quantity V to the point C. Since the vector quantity V is added to the potential of the terminal 64 (point A), the output operate quantity appearing between the first andsecond terminals 74 and 76 of the first pair of output terminals may be represented by the vector F and the output polarizing quantity appearing between the first andsecond control terminals 76 and 106 of the second pair of output terminals may be represented by the vector E which is the vector quantity resulting from the addition of the vector quantity V to the point C.

The three-phase faultpolarizing signal network 56 provides a voltage which leads the voltage between the conductors 34-32 by an angle which is illustrated as being ninety degrees and is vectorially illustrated by the vector E For this purpose thenetwork 56 comprises aphase shifting network 107 and amemory network 108. Thephase shifting network 107 comprises an impedance having a center tapped winding 109, a capacitor and avariable resistance 112. The winding 109 is connected between theinput terminals 64 and 66 whereby it is energized with a voltage derived quantity representing the potential between conductors 34 and 32 and represented in the vector diagrams by the vector E As indicated, the connection fromterminal 64 is adjustable to control the magnitude of the output potential of thenetwork 107. The capacitor 110 and thevariable resistor 112 are connected in series between the upper and lower end terminals of the winding 109. The output potential of thephase shifting network 107 is derived fgom thecenter tap 118 of the winding 109 and the common connection or terminal 120 between the capacitor 110 and theresistor 112.

Thememory network 108 comprises an inductor and a capacitor connected in series between the terminal 116 and thecenter tap 118. This network is tuned to the frequency of thenetwork 1 so that it will provide for a continued energization of thecontrol terminals 114 and 116 for a short interval following termination of the voltage appearing between the conductors 32 and 34, such as may occur in the event of a fault between these two conductors (A-B fault).

Thecontrol terminals 74, 76, 106, 114 and 116 of thelogic network 22 are connected respectively to inputterminals 124, 126128, 130, 132 and 134 of the tripcoil actuating network 16. The connection from the terminal 76 to theterminals 126 and 128 includes a balancingresistor 136 having its resistor terminals connected between theterminals 126 and 128 and itsmovable tap 138 connected to the terminal 76. Thenetwork 16 comprises threetransformers 140, 142 and 152 having their primary windings individually connected between the terminals 124-126, 128-130 and 132-134 respectively.

As will be brought out in greater detail below, it is desirable that the output voltages supplied by thetransformers 140, 142 and 152 remain above a critical effective magnitude substantially throughout the entire degrees of each half cycle and that such voltage remains within reasonable limits. A suitable wave shape is a square wave. A convenient structure forobtaining such a voltage wave is the provision of clipping devices which will limit the magnitude of the potential supplied to the primary windings of the transformers. As diagrammatically illustrated this is accomplished by connecting two oppositely poledZener diodes 148, 150 and 156 in shunt with the primary windings of thetransformers 140, 142 and 152 respectively. Transient suppressing networks comprising a capacitor connected in series with a resistor across the primary windings of these transformers may be used to eliminate or reduce the occurrence of spurious signals at the output orsecondary windings 144, 146 and 154.

The tripcoil actuating network 16 comprises a fault operatecircuit 158, a line to line faultpolarizing circuit 160, a three-phase faultpolarizing circuit 162, arestraint squelch circuit 164, avoltage detecting circuit 166 and a trip amplifier control circuit 168. Unidirectional power for the trip coil actuating network is provided from a suitable source of supply such as the station battery and is diagrammatically indicated by terminals identified by +DC and -DC. In order that the voltage between the positive andnegative DC buses 174 and 176 may be held at a desired constant value, thebus 174 is connected to the +DC terminal through avoltage dropping resistor 178 and to thenegative bus 176 through a voltage regulating device which may be of aZener diode 180. Acapacitor 190 is connected between the buses 174.and 176 to aid in the attainment of the constant potential therebetween.

The fault operatecircuit 158 is actuated from the center tapped secondary winding 144 of thetransformer 140 which controls the conductive condition of thetransistors 192 and 194; thetransistor 192 being rendered conductive during the polarity-positive half cycles and the transistor 194 being rendered conductive during the polarity-negative half cycles of the output signal of thetransformer 140. Amplifyingtransistors 196 and 198 are utilized to amplify the output signals of the winding 144 and control thetransistors 192 and 194. The base of thetransistor 196 is connected to upper terminal of the winding 144 through a current limiting resistor and diode 'and the emitter is connected to the center tap of the winding 144. The collector-emitter circuit of thetransistor 196 extends from thepositive bus 174 through avoltage dropping resistor 200 to thenegative bus 176. The control circuit of thetransistor 192 extends from thepositive bus 176, the emitter-base of thetransistor 192, a current limiting resistor, and the collector-emitter circuit of thetransistor 196 to thenegative bus 176. The emitter oftransistor 192 is connected to thepositive bus 174 and its collector is connected to acommon terminal 202 of a pair ofvoltage dropping resistors 204 and 206 connected between the terminal 202 and a pair ofterminals 208 and 220 respectively. The terminal 208-is connected through afirst diode 210, asecond diode 212 and aZener diode 214, to the base of atransistor 216 of the trip amplifier control circuit 168. The emitter of thetransistor 216 is connected by aconductor 218 to thenegative bus 176.

The free end of theresistor 206, which is energized concurrrently with theresistor 204, is connected to a terminal 220 and therefrom throughdiodes 222 and 224 and theZener diode 214 to the base of thetransistor 216. The emitter of thetransistor 216 is connected by aconductor 218 to thenegative bus 176 and the collector is connected through avoltage establishing resistor 226 to thepositive bus 174. Whentransistor 216 conducts, a signal will be established between theoutput terminals 228 and 230. Theseterminals 228 and 230 are connected to the upper and lower input terminals respectively of theamplifier network 8. As will be described below, the conduction oftransistor 216 results in energization of the trip coil 6 of the circuit. breaker 4 and opening of the circuit breaker contacts to disconnect thebranch 2 from the three-phase power network 1.

The transistor 194, which functions during the opposite half cycle to thetransistor 192, has its emitter connected to thebus 174 and its collector connected to acommon terminal 232 of a pair ofresistors 234 and 236. The other end terminals of the resistor are connected toterminals 238 and 240 respectively; The terminal 238 is connected throughdiodes 242, 212 and 214 to the base of thetransistor 216. Similarly, the terminal 240 is connected throughdiodes 244, 224 and 214 to the base of thetransistor 216.

Conduction of the transistor 194 is controlled by thetransistor 198 and for this purpose the base thereof is connected to thenegative bus 176 through the collector oftransistor 198 and the usual current limiting resistor. The base of thetransistor 198 is connected through a diode and current limiting resistor to the lower end terminal of the transformer winding 144 and its emitter is connected directly to the center tap connection thereof.

In order to prevent energization of the trip coil 6 except in response to fault on thenetwork branch 2, theterminals 208, 220, 238 and 240 are selectively directly connected to thenegative bus 176 by thepolarizing circuits 160 and 162 in shunt with the base circuitcof thetransistor 216. Since these shunt circuits inevitably have some resistance therein, aZener diode 214 is selected which has a breakover potential which is in excess of such voltage drop. This assures that no base current will flow to thetransistor 216 from any of theterminals 208, 220, 238 and 240 which are shunted to thenegative bus 176.

The shunt circuit for the terminal 208 extends therefrom through a discontinuoustype control device 246 such as, a silicon controlled rectifier and abranch bus 248 to thenegative bus 176. The shunt circuit for the terminal 238 extends therefrom through anotherdiscontinuous control device 250 such as the silicon controlled rectifier andbus 248 to bus176. Likewise, the shunt circuits for theterminals 220 and 240 extend throughdiscontinuous control valves 252 and 254 respectively which may be silicon controlled rectifiers and abranch bus 256 of the three-phase faultpolarizing circuit 162 to thenegative bus 176.

I As will be brought out more clearly below, the operation of the relaying controlling apparatus with an unfaulted condition of thenetwork 2 is such that the phase of the output signals of thetransformers 142 and 152 lead the phase of the output signal of the transformer whereby the controlledrectifiers 246, 250, 252, and 254 are gated into conductivity prior to the time that thetransistors 192 and 194 are rendered conducting. With such a phasing, the potential of theterminals 208, 238, 220 and ,240 cannot increase substantially above ground potential when thetransistors 192 and 194 actually conduct. The breaker 4 will therefore remain in its circuit closing position to connect thenetwork branch 2 to the network. The gate of the controlledrectifier 246 is connected to the upper terminal of the winding 146 through a current limitingresistor 247 and adiode 249 while the cathode is connected to the center terminal through abus 248. A usual shunting resistor shunts the gate and cathode. The gate of the controlledrectifier 250 is connected to the lower terminal of winding 146 through another current limitingresistor 251 and adiode 258 and the cathode is connected to thebranch bus 248. A shunting resistor is connected between the gate and cathode of therectifier 250 During the periods in which the upper terminal of the winding 146 is positive with respect to the center tap connection, the gate of the controlledrectifier 246 Will be maintained in condition for anode to cathode conduction of the controlledrectifier 246 upon the conduction oftransistor 192 and similarly during the periods in which the lower terminal of the winding 146 is positive with respect to the center tap, the controlledrectifier 250 will be in readiness to conduct upon conduction of the transistor 194. The controlledrectifiers 246 and 250 are of the discontinuous control type in that when once rendered conductive they will conduct as long as anode cathode voltage is maintained thereacross. Therefore these controlledrectifiers 246 and 250 will continue to conduct and hold theterminals 208 and 238 substantially at ground potential for the time period that thetransistors 192 and 194 conduct even though the gate signal subsequently terminates.

Similarly, the controlledrectifiers 252 and 254 have their gate and cathode circuits connected to the transformer winding 154 whereby these rectifiers are rendered in a conducting condition whenever thetransformer 152 is energized. Theserectifiers 252 and 254 act in a manner similar to therectifiers 246 and 250 and maintain thecompanion terminals 220 and 240 substantially at ground potential when they conduct.

Therestraint squelch circuit 164 is provided to shunt the gate current from the controlledrectifiers 246 and 250 in instances in which thetransistors 192 and 194 are rendered conducting prior to the rendering of the controlledrectifiers 246 and 250 conducting. Therestraint squelch circuit 164 includes twotransistors 260 and 264 with their base emitter circuits connected between theterminals 202 and 232 and thenegative bus 176 through the usual current limiting resistors. The collector of thetransistor 260 is connected to the common connection of theresistor 247 anddiode 249 through a diode 261. The collector is also connected to the common connection of resistor and diode which connects upper terminal of thetransformer 152. This connection includes a diode to prevent current flow except toward thetransistor 260. The emitter of thetransistor 260 is connected to anegative branch bus 262. When thetransistor 192 conducts, the terminal 202 is elevated in potential and base current flows through the transistor 260'rendering it conductive and thereby effectively shunting any gate current from the controlledrectifiers 246 and 252. Similarly, the base of thetransistor 264 is connected through a usual current limiting resistor to the terminal 232, the emitter is connected to thebranch bus 262 and the collector is connected through diodes to the gate circuits of the controlledrectifiers 250 and 254. Therefore whenever the transistor 194 conducts, thetransistor 264 is rendered conductive whereby the potential of the gates of the controlledrectifiers 250 and 254 are maintained at substantially the potential of thenegative bus 176 and the controlledrectifiers 250 and 254 cannot be rendered conducting. With this arrangement the effect of the conduction of thetransistors 192 and 194 cannot be nullified if they are rendered conducting prior to the rendering of any of the controlledrectifiers 246, 250, 252 and 254.

Thevoltage detecting circuit 166 prevents an incorrect tripping of the breaker 4 by the operate circuit even though one or both of the polarizing voltages established by thetransformers 142 and 152 should disappear. Thiscircuit 166 includes thetransistors 265, 266, 267 and 268.Transistor 265 controls the conduction oftransistor 266 each of which has its emitter connected tonegative branch bus 270. The collector oftransistor 265 is connected through avoltage dropping resistor 269 to thepositive bus 174. The collector of thetransistor 266 is connected to the common connection of thediodes 210 and 212. Base current for thetransistor 265 is derived from thetransformer 142 through theconnection 271 and the diodes 272 and 273, and will conduct at all times that thetransformer 142 is energized. Since the base of thetransistor 266 is connected to the common connection of theresistor 269 and the collector of thetransistor 265, the transistor is normally maintained non-conducting. If, however, the output voltage of the faultpolarizing network 54 fails and thetransistor 265 becomes non-conducting, the base of thetransistor 266 will increase in potential, base current will flow andtransistor 266 will conduct to shunt away any base drive to thetransistor 216 from theterminals 208 and 238.. Similarly thetransistors 267 and 268 are actuated in response to the presence or absence of the output signal from the 3 faultpolarizing network 56 to permit or shunt away the base drive signal to thetransistor 216 from theterminals 220 and 240.

Theamplifying network 8 as discussed above is provided with three sets ofinput terminals 10, 12 and 14. The lower terminal of each of thesets 10, 12 and 14 is connected through a current limitingresistor 276 to the base of atransistor 278 while the upper ones of each of the sets ofterminals 10, 12 and 14 is connected to the emitter. Emitter-collector potential is applied to thetransistor 278 from a suitable direct current source connected between the positive andnegative buses 280 and 282. Adiode 284 is connected between the emitter of thetransistor 278 and thebus 280. Aresistor 286 is connected between the collector of thetransistor 278 and thenegative bus 282. The potential across theresistor 286 is used to energize an RC circuit consisting ofresistor 294 andcapacitor 298 connected in series circuit with each other and in shunt with theresistor 286. The potential acrosscapacitor 298 is used to energize apulse transformer 288 through aShockley type diode 292 and for this purpose theprirnary winding 290 of the transformer has one end connected to one terminal of thecapacitor 298 and its other end connected through aShockley type diode 292 to the other terminal of the capacitor. Reverse current is prevented from flowing through thediode 292 by means of adiode 296 connected in antiparallel therewith.

The secondary winding 300 of thetransformer 288 is connected between the gate and cathode of a controlledrectifier 302 through a current limiting resistor 304. The anode of therectifier 302 is connected through a current limitingresistor 306 to thepositive bus 280 and its cathode is connected through the trip coil 6 of the breaker 4 to thenegative bus 282. In order to limit the forward voltage across the controlledrectifier 302 it may be and preferably is shunted by aZener type diode 308. Acapacitor 310 series connected with a current limitingresistor 312 is shunt connected with the relay 6 to permit a more rapid buildup of current through the controlledrectifier 302 than would occur through the inductive trip coil 6 by itself. This feature is shown and claimed in my copending application Ser. No. 422,297 filed Dec. 30, 1964 for Control Device.

The output connection of theactuating networks 18 and 20 are connected to theinput circuits 12 and 14 respectively of theamplifying network 8 throughtime delaying devices 314 and 316. These devices may take any desired form which will produce a time delay between the time of energization of its input and the energization of its output so that the actuation of theamplifying network 8 and thereby the trip coil 6 may be delayed for first and second predetermined time intervals so that thezone 2 andzone 3 controls operate as back up devices in accordance with accepted relaying practice. The first time interval is preferably of lesser duration than the second time interval. An illustration of the use of back up apparatus may be found in my said Patent No. 2,973,460 as well as in protective relaying texts.

It is believed that the remainder of the details of construction may best be understood from a description of the operation of the apparatus which is as follows: The vector diagrams of FIGS. 3 and 3A vectorially illustrate the operation of the apparatus when thebranch network 2 is unfaulted. As is more particularly brought out in FIG. 3A the phase of the operate signal E on transformer lags both of thevoltages E 3,, and EP3c supplied by thetransformers 142 and 152. The voltagepotential transformer array 28 energizes theconductors 38, 40 and 42 with voltages having phase angles and magnitudes proportional to the voltages found between thenetwork conductors 32, 34 and 36. The voltage between theconductors 38 and 40 is applied to the winding 60 of thetransformer 58 between the common tap 75 thereof, and a primary winding tap a, b or c. The voltage between theconductors 42 and 40 is applied to the wind- 9ing 90 of the transformer 88 by connectingconductor 40 to thetap 78 and conductor 42 to the proper tap a, b or c of the winding 90' in a manner like that set forth in my said patent. Thetransformer 58 is energized With a potential proportional to that between the line conductors 32 and 34. The transformer 88 is energized by a potential proportional to that between theline conductors 34 and 36. In FIG. 3, theline conductors 32, 34 and 36 are represented by the reference characters A, B and C. The voltage which appears across the output winding 62 and the common portion of the winding 60 is represented by the vector E andthat'which appears across the winding 92 and the common portion of the winding 90 is represented by the vector E The output voltages which appear across theoutput terminals 74 and 76 of thelogic networks 22, 24 and 26 are phase shifted with respect to the E and E vectors by an amount as determined by the compensators or summingdevices 72. Thedevice 72 is energized by the line current flowing in the conductors 32 and 34 and is represented by the vectors I and I These two vectors add together to provide a summed quantity I The potential across the winding 70 developed by the quantity I is phase shifted as determined by thephase shifting network 86 to provide an output compensated quantity which is represented by the vector V This summed quantity is added to the output quantity of thetransformer 58 to provide a voltage between the output terminals which is represented by the vector E This output voltage is applied to the primary winding of thetransformer 140 of the fault operatecircuit 158. Due to the presence of the, diagrammatically illustrated, back-to-back Zener diodes 148, the magnitude of the voltage applied to the primary winding of the transformer is limited in magnitude of that a substantially square wave of voltage is applied. The magnitude of this voltage is so related to its frequency and with respect to the core of the transformer that thetransformer 140 does not saturate and produces an equivalent square wave output voltage at its secondary winding 144. The phase of this output is represented in the vector diagram of FIG. 3A by the voltage vector E The voltage added by the compensator or summingde vice 96 is derived from the vector sum of the currents flowing in theconductors 34 and 36 represented by the vectors I and -I;;. These quantities are vectorially added together and phase shifted by thenetwork 102 to provide a summed quantity V This quantity adds to the quantity at the point C of the vector diagram to provide a quantity atterminals 76 to 106 which is represented by the vector E in FIG. 3. This quantity is applied to the primary winding of thetransformer 142, and is clipped by the diagrammatically"illustrated back-to-back Zener diodes 150 to provide a square wave of'a phase illustrated in vector diagram FIG. 3A by the vector quantity E The three-phasepolarizing signal network 56 is energized by the voltage appearing between theconductors 38 and 40'which is representative ofthe voltage between the conductors 32 and 34 and represented in the vector diagram of FIG. 3 by the voltage E This voltage is phase shifted by thenetwork 56 to provide a voltage at itsoutput terminals 132 and 134 which is phase shifted to lead the voltage E This quantity is represented in FIG. 3 by the voltage vector E This voltage is clipped by the diagrammatically represented back-toback Zener diodes 156 and thetransformer 152 is energized by a substantially square wave which is phased 90 leading with respect to the voltage E The phase of this quantity is represented in FIG. 3A by the vector E FIG. 3A shows that each of the polarizing voltages Ep3 c and E leads the operating voltage E during normal operation of thenetwork branch 2 by an angle which is less than 180. With this phasing, thetransistors 192 and 194 are rendered conducting when the polarizing Voltages are maintaining the controlled rectifiers 246-252 and 250-254, respectively ready to conduct. Therefore, as soon as the lagging operating voltage E causes thetransistors 192 and 194 to conduct, the voltage drop between the terminals 208220 and 238240 and thenegative bus 176 is less than the critical or breakover voltage of theZener diode 214 and no base current will be supplied to cause thetransistor 216 to conduct. Since thetransistor 216 does not conduct, there is no drop across theresistor 226 and both of theoutput terminals 228, 230 thereof remain at the same potential, the amplifyingnetwork 8 remains unactuated and the trip coil 6 remains deenergized. Should the potential E betweenconductors 34 and 36 fail for any reason as for example due to a fault onnetwork 1 closely adjacent the breaker 4, the voltage E would not be effective to render the controlledrectifiers 246 and 252 in readiness to conduct so that the potential of theterminals 208 and 238 would be elevated to supply a base drive totransistor 216 to actuate thenetwork 8 to energize the trip coil 6 which results in an undesired tripping of the breaker 4.

This undesired tripping is prevented by thevoltage detecting circuit 166. When thetransformer 142 becomes deenergized, the base drive for the transistor 2'65 terminates and thistransistor 265 becomes non-conducting. This results in an increase in the potential of the base of thetransistor 266 whereby base current flows and thetransistor 266 conducts. This conduction of thetransistor 266 connects theterminals 208 and 238 to thenegative bus 176 through thediodes 210 and 242 thereby preventing base current flow from these terminals to thetransistor 216. Similarly should the voltage E fail for any reasons, thetransistor 267 will fail to conduct whereby thetransistor 268 will conduct to connect theterminals 200 and 240 to thenegative bus 176 and thereby prevent base current flow therefrom to thetransistor 216 and undesired tripping of the breaker 4.

FIG. 4, shows vectorially the conditions which occur when the lines 32 and 34 in thebranch network 2 become faulted within the reach of thezone 1 equipment. When such a fault occurs, the potential E decreases in magnitude depending upon the distance from the equipment to the fault location. Such decrease is assumed to be the magnitude E Since the lines 32 and 34 are faulted together, the current flowing in conductor 32 is identical to that in conductor 34 except that the direction of the two currents is reversed. This fault current is represented in the vector diagram by the vectors I and -I Since substantially no load current flows in the faulted lines 32 and 34 the phase angle of the current is substantially that of the impedance of thebranch network 2. Thephase shifting network 86 is adjusted so that the phase of the compensating quantity V is out of phase with the voltage E The high volts per turn of the windings of thetransformer 72 provides a compensating quantity V which is substantially greater than the voltage E The resulting potential E at theterminals 74 and 76 is opposite in phase substantially 180 out of phase with the voltage E I.

A voltage V derived primarily from the I current since the current in theconductor 36 is of so small magnitude with respect to the current in the conductor 34. This current I is represented by the vector I extending from the point C in FIG. 4. The phase shift imparted by thephase shifting network 102, which is preferably the phase angle of thebranch network 2 phases the voltage V due to the current I which is added by the winding 94 to the output voltage of the transformers 88 to provide an output quantity E between theterminals 108 and 76. This voltage E is applied across the primary winding of thetransformer 142 andZener diodes 150. The phase angle of the output voltage of this transformer winding 146 is represented in FIG. 4A by the vector E and lags the phase of the operate voltage E by an angle somewhat less than 180. With this phasing of the vectors E and E thetransistors 192 and 194 will be rendered conducting prior to the rendering of the controlledrectifiers 246 and 250 conducting whereby base current will flow from thepositive bus 174 through thetransistors 192 and 194 and theZener diode 214 to thetransistor 216. When so controlled, thetransistor 216 conducts to establish a voltage across the resistor orvoltage establishing impedance 226.

Theterminals 228 and 230 are connected between the upper and lower terminals respectively of theinput 10, so that base current flows through thetransistor 278 which thereupon conducts to energize the voltage establishing resistor orimpedance 286. The voltage established by theimpedance 286 with thetransistor 278 conducting is sufficient to breakover the fourlayer device 292 and cause the primary winding 290 of thetransformer 288 to be energized. The potential induced in the winding 300 causes gate current flow and renders thecontrol rectifier 302 conducting. This causes an energizing current to the trip coil 6 which thereupon releases the breaker trip and the circuit breaker 4 opens to disconnect thenetwork branch 2 from thenetwork 1.

In order to prevent any subsequent conduction of the controlled rectifiers 246-252 and 250 254, the gate signals thereto are shunted by thetransistors 260 and 264 respectively of therestraint squelch circuit 164. When thetransistor 192 conducts, it energizes the terminal 202. This causes base current to flow base to emitter in thetransistor 260 to thereby turn on thetransistor 260 and effectively connect the gates of the controlledrectifiers 246 and 252 to thenegative bus 176 to which the rectifier cathodes are connected. Therefore when the upper terminals of thewindings 146 and 154 become positive, the current caused to flow thereby flows to the center terminal of thewindings 146 and 154 through thetransistor 260 rather than through the gate circuits of the controlledrectifiers 246 and 252 as would otherwise occur. Thetransistor 264 is similarly rendered conducting as a consequence of the conduction of the transistor 194 to shunt the gate current from the controlledrectifiers 250 and .254 to prevent their being rendered nonconducting when the lower end terminals of thewindings 146 and 154 become positive with respect to their midtaps.

When the breaker 4 opens the contacts 4a thereof will open the circuit through therectifier 302. The opening of the breaker 4 disconnects the network branch from thenetwork 1 and interrupts the fault current. Thelogic network 22 will no longer indicate a faultedbranch 2 and the tripcoil actuating network 16 will become deenergized.

Let us now suppose that the fault between the conductors 32 and 34 was not located intermediate the breaker 4 and the next subsequent breaker but was located beyond the next subsequent breaker or inzone 2. In such event, and assuming only fault current flows in the conductors 32 and 34 the magnitude of the currents I and -I as illustrated in FIG. 4 would be sufiiciently small so that the summed quantity V would be less than the voltage E which voltage, under these conditions, would be greater. Vectorially the points B and A would be further apart and nearer their respective unfaulted voltage positions B and A, respectively. The direction of the output vector E would be reversed as would that of the vector E The polarizing vector E would then lead the operate vector E with the results that the controlledrectifier 246 and 250' would connect theterminals 208 and 238 to thenegative bus 176 and no base current would flow to thetransistor 216. The breaker would not be unwantedly opened. Thezone 2 apparatus, however, has the terminal 64 connected to the b tap of the winding 60. This in effect reduces the magnitude of the voltages E and E with respect to the magnitude of the quantities V and V Therefore the magnitude E of thezone 2 fault is sufficiently reduced in magnitude relative to the quantity V such that the operate vector E will remain in the direction as shown in FIG. 4A. Compensation may also be made by the adjustable windings of thecompensators 72 and 96.

Inzone 3, theterminals 64 and 68 are connected to the outer end taps c of the windings 60 and and/ or the adjustment of thewindings 82, 84, 98 and 100 may be altered to provide for the still further reach of thezone 3 apparatus.

Thezone 2 andzone 3 apparatuses actuate theamplifying network 8 throughtime delay networks 314 and 316 while thezone 1network 158 is instantaneous. Therefore even though thezone 2 andzone 3networks 18 and 20 are actuated by a fault inzone 1, they are ineffective to actuate theamplifying network 8. If however, the fault is beyond thatzone 1 balance point of the illustrated relay but is within its zone 2 (zone 1 of the relay at the next control station) and thezone 1 relay at the next station fails to open the breaker, then after the time delay of thenetwork 314, the faulted line network section will be disconnected by the illustrated breaker 4.

The connection of thecurrent windings 82, 84, 98 and 100 of the compensators or summingdevices 72 and 96 to theconductors 44, 46 and 48 are shown as being adjustable in order to correlate further the magnitude of the vectors I I and I with respect to the current in theconductors 32, 34 and 36. This adjusts the impedance balance points to which thedistance logic networks 22, 24 and 26 are responsive.

FIG. 5 shows the vector quantities which exist when a fault occurs between theconductors 34 and 36 within the first zone. In this event, the voltage E collapses to the voltage E I, the current I is negligible with respect to thecurrents 1 and I The current I is equal and opposite to the current 1 as indicated in the vector diagram. The compensating quantity is represented by the vector V and the operate voltage applied to theterminals 74 and 76 is represented by the vector E The currents :I and I together with thephase shifting network 102 provide a compensating quantity V g, Which is added to the potential E provides a polarizing voltage E which is in phase with the voltage E and equal to the difference between the quantities represented by the vector E and the vector V This voltage is applied to thetransformer 142 and appears at the winding 146 as a quantity represented by the vector E as shown in FIG. 5A. The voltage at the winding 144 of the transformer is represented by the vector E The vector E leads the polarizing vector E whereby theterminals 208, 238 will be raised in potential to supply base current to and render thetransistor 216 conducting. The voltage vector El which leads the vector E by less than will cause the controlledrectifiers 252 and 254 to conduct but this is of course without effect since conduction of thetransistor 216 will occur due to the lagging of the fault polarizing signal Ep c.

FIG. 6 illustrates, Vectorially, the operation of the apparatus upon the occurrence of a fault betweenconductors 32 and 36 within the first zone. In this event, current 1 and I are equal and opposite and current 1;; is substantially zero. The operate voltage E and polarizing voltage E are supplied to thetransformers 140 and 142. The output voltage of these transformers are illustrated in FIG. 6A as E and E provide for operation of thetransistor 216. It will be noted that in the line 32 toline 36 fault, the angle of lead of the operate voltage with respect to the polarizing voltage is small. Therestraint squelch circuit 164 prevents subsequent actuation of the controlledrectifiers 246 and 250 and a sufiicient signal is provided to operate theamplifier 8 to trip the breaker 4.

FIG. 7, illustrates Vectorially the relationships which occur for a three-phase fault in which theconductors 32, 34 and 36 are shorted together and provide the voltage triangle A, B and C. In the case of a three phase fault, all three line currents I 1;; and 1 are present as fault 13 chi-rents and each will be phased with respect to the three phase voltage which exists between theconductors 32, 4 and 36 and a neutral voltage at phase angledete'rmined by the impedance of thenetwork branch 2. The summed quantities I and I are phase shifted by thenetwork 86 and 102 and appear as compensating quantities V and V These compensating quantities are added to the corresponding phase voltage quantities A, B and C and provide operate and polarizing voltages E E andE 3 as illustrated in FIG. 7A. It will be obvious in this instance that the polarizing voltage E leads the operate voltage E However, the polarizing voltage E provided by the three-phase faultpolarizing signal network 56, is however, phased 90 ahead of the voltage E and is in lagging relation with respect to the voltage E which enables thetransistor 216 to be rendered conducting to actuate theamplifying network 8 for energization of the trip coil 6 and opening of the breaker 4 as above described.

.While back-to-back Zener diodes 148, 150 and 166 are illustrated, it will be apparent that anti-parallel arranged conventional diodes may be provided and enough thereof connected in series so that the forward drop in each direction is equal to the desired magnitude of voltage for application to the primary winding of thetransformers 140, 142 and 152. It will be apparent that the magnitudes of the output voltages of thetransformers 140, 142 and 152 is not important providing they are sufficient to trigger the various semiconducting devices. It is the phasing of these quantities which acutally performs the controlling operation.

, Although the invention has been described with reference to a single embodiment thereof, numerous modifications are possible and it is desired to cover all modifications falling within the spirit and scope of the invention.

What is claimed and is desired to be secured by United States Letters Patent is as follows:

1. In a relaying system for a three phase network, a first plurality of input terminals supplying a three phase electrical quantity which is proportional to the potential of a three phase network from which said first terminals are energized, a second plurality of input terminals supplying a three phase electrical quantity which is proportional to the current flowing in a three phase network from which said second terminals are energized, first and second and third pairs of output terminals, first and second compensators, each said compensator including input means and output means and effective to energize its said output means with a compensating vector quantity which is the vector sum of electrical quantities supplied to its said input means, each said compensator further including means to shift the phase of its said compensating vector quantity with respect to said vector sum of said electrical quantities supplied thereto, first circuit means connecting a first pair of 'said first input terminals to said first pair of output terminals and including said output means of said first compensatorwhereby said first pair of output terminals is energized by the vector sum of the said quantities which are supplied to said first circuit means by said first pair of input terminals and said first compensator, a second circuit means connecting a secondpair of said first input terr'ninals tosaid second pair of output terminals and including said output means of said second compensator whereby said second pair of'output terminals are energized by the vector sum of the-said quantities which are supplied to said second circuit means by said second pair of input terminals and said second compensator, a phase shifting cirwit, a third circuit means connecting said first pair of input terminals to said third pair of output terminals and including said phase shifting circuit whereby the phase ofthe said quantity which is supplied to said third pair of output terminals may be phase shifted with respect to the phase of the said quantity supplied to said third circuit means from said first pair of input terminals, means connecting said input means of said first compensator to a first group of terminals of said second plurality of terminals to supply a first current compensating quantity to said first compensator which is representative of the difference between a first phase quantity and a second phase quantity of said three phase quantity supplied by said second plurality of input terminals, means connecting said input means of said second compensator to a second group of terminals of said second plurality of terminals to supply a second current compensating quantity to said second compensator which is representative of the difference between two phase quantities of said three phase quantity supplied by said second plurality of input terminals, and a phase sensitive control circuit connected to said pairs of output terminals and effective when the phase of said quantity of a predetermined pair of said output terminals is leading in phase relationship with the phase of either of said quantities of the other two of said pairs of said output terminals.

2. The combination ofclaim 1 in which both said plurality of input terminals are supplied from the same three phase network, said first pair of said first plurality of input terminals being energized by a first phase of said three phase network, each said groups having first and second pairs of terminals, a first pair of terminals of said first group of terminals being energized by said first phase of said three phase network, said predetermined pair of said output terminals being energized by said first phase of said three phase network, said second pair of said first plurality of input terminals being energized by a second phase of said three phase network a first pair ofterminals of said second group of terminals being energized by said second phase of said three phase network, said second pairs of terminals of said first and second groups of terminals being energized by a third phase of said three phase network.

3. The combination ofclaim 2 in which the phase rotation of said network is phase first and phase third and phase second and in which the phase angle of said current quantities with respect to their respective voltage quantities of said first pair of terminals of said first and second groups of terminal groups is not greater than ninety degrees, said voltage quantities being derived from said first and second pairs of said first plurality of input terminals respectively.

4. In a relaying system for a three phase network having conductors, means adapted to be connected to said network to derive therefrom first and second electrical voltage originated quantities representing the voltages between a second and a first of said conductors and between a third and said second of said conductors, means adapted to be connected to said network to derive therefrom third and fourth and fifth current originated electrical quantities representing the current in said first and said second and said third conductors respectively, said current quantities being considered positive when the phase angle thereof relative to the voltages which causes said respective current quantity is ,not in excess of degrees and negative when such phase angle is greater than 90 degrees, first and second and third control output circuits, first circuit means vectorially supplying to said first output circuit said first quantity and said third quantity and said fourth quantity, said fourth quantity being in the negative direction and said third quantity being in the positive direction, second circuit meansvectorially supplying to said second output circuit and said second quantity and said fourth quantity and said fifth quantity, said fourth quantity being in the negative direction and said fifth quantity being in the positive direction, and third circuit means supplying a sixth electrical quantity to said third output circuit, said sixth quantity being representative of an alternating voltage of the same frequency as that of said network and phased to lead said first quantity.

5. In a relaying system for a three phase network having conductors, means adapted to be connected to said network to derive therefrom first and second electrical voltage originated quantities representing the voltages between a second and a first of said conductors and between 15 a third of said conductors and said second conductor, means adapted to be connected to said network to derive therefrom third and fourth and fifth current originated electrical quantities representing the current in said first and said second and said third conductors respectively,

said current originated quantities being considered positive when the phase angle thereof relative to the voltages which cause said respective current quantity is not in excess of 90 degrees and negative when such phase angle is greater than 90 degrees, first and second and third control output circuits, first circuit means vectorially supplying to said first output circuit said first quantity and said third quantity and said fourth quantity, said fourth quantity being in the negative direction and said third quantity being in the positive direction, second circuit means vectorially supplying to said second output circuit said second quantity and said fourth quantity and said fifth quantity, said fourth quantity being in the negative direction and said fifth quantity being in the positive direction, and third circuit means supplying said first quantity to said third output circuit, said third circuit means including said phase shifting means for shifting the phase of said first quantity which is supplied to said third output circuit in a direction to lead the phase of said first quantity which is supplied to said first circuit means.

6. The combination of claim in which there are provided first and second and third transformers, each said transformer having a primary winding and a secondary winding, said first and second and third output circuits being individually connected across said primary windings of said first and said second and said third transformers respectively, and a plurality of impedance means, individual one of said impedance means being connected in shunt with an individual one of said windings of each of said transformers, each said impedance means being characterized by the part that it will maintain a substantially constant voltage of predetermined magnitude thereacross in either polarity when energized with a voltage having a magnitude in excess of said predetermined magnitude, said predetermined magnitude being substantially less than the magnitude of the output quantities of said output circuits, and said transformers being of the non-saturating type whereby substantially square output voltage waves are obtained from said secondary windings.

7. The combination of claim 6 in which there is provided at least one switching circuit, each said switching circuit comprising first and second and third switches and first and second impedance devices, each said switch having a main circuit and a control circuit, said first switch being of the continuous control type in which its said control circut is operable to initiate and terminate current flow through its said main circuit, said second and third switches being of the discontinuous control type in which their said control circuits merely control the initiation of current flow through their respective said main circuits and current therethrough is terminated by other means, each said switching circuit being arranged with its said first impedance device connected in series with and intermediate said main circuits of its said first and second switches and being arranged with its said second impedance device connected in series with an intermediate said main circuits of its said first and third switches, means individually connecting said control circuits of said first and said second and said third switches to said secondary windings of said first and said second and said third transformers respectively, a load circuit,'

and means connecting said load circuit in shunt circuit with at least one said main circuit of said second and said third switches.

8. In a relaying system for a three phase network having a normal phase rotation such that the first and second and third conductors thereof reach their maximum voltages in the order mentioned, potential means for association with said network for obtaining therefrom first and second potential derived electrical quantities representative of the first and third phase voltages of said network which appear between said second and first conductors and between said third and second conductors respectively, current means for association with said network for obtaining therefrom third and fourth and fifth current derived electrical quantities representative of the first and second and third phase currents which flow in said first and second and third conductors respectively, said current and potential quantities being considered as being in a positive direction when the phase of such quantities is the same as the phase of the corresponding current and voltage in said network when power flows through said network in a predetermined direction, said quantities being considered as being in a negative direction when the phase thereof is reversed from said positive quantity, first and second summing networks each said summing network having input and output connections and phase shifting means, each said summing network being eifective to deliver to its said output connection an output quantity which has a phase angle deter mined by the vector sum of the electrical quantities supplied to its said input connections and the magnitude of phase shift of its said phase shifting means, means de livering to said input connection of said first summing network said first and third quantities in their said positive directions and said fourth quantity in its said negative direction, means delivering to said input connections of said sec-ond summing network said second and fourth quantities in their said positive directions and said fourth quantity in its said negative direction, each said phase shifting means being operable to phase shift the vector sum of the electrical quantities supplied to the said input connections of its respective said summing network by an angle equal to the impedance angle of said three phase network, a phase shifting apparatus having input terminals and output terminals and being operable to phase shift an electrical quantity applied to its input terminals by a desired angle, and means energizing said input terminals of said phase shifting apparatus by said first electrical quantity, said phase shifting apparatus being effective to phase shift said first quantity such that the quantity of its said output terminals leads the voltage of the first phase of said three phase network by substantially degrees.

9. The combination ofclaim 8 in which there is pro.- vided a load controlling network characterized by the fact that it is actuated when the phase of a first of three alternating voltages applied thereto is leading in phase with respect to either of the second and third of said voltages and is ineffective when said first voltage lags both of said second and said third voltages, said circuit means energizing said load controlling network from said summing networks and said phase shifting apparatus, the output quantity of said first summing network being said first voltage. 4

10. The combination ofclaim 8 in which there is provided a pair of load controlling circuits, each said circuit including a phase responsive control means, each said phase responsive control means including first and second input connections and an output circuit and characterized by the fact that when the phase of a pulsating electrical quantity applied to its said first input connection is leading in phase with respect to the phase of a pulsating electrical quantity applied to its said second input connection its said output circuit is rendered effective and when the phase of a pulsating electrical quantity applied to its said second input connection is leading with respect to the phase of a pulsating electrical quantity applied to its said first input connection its said output circuit is heldine'ffective, means connecting said first in,- put connection of each of said phase responsive control means to said output connection of said first summing network, means connecting said second input connection of a first of said phase responsive control means to said output qonnection of said second summing network, and

17 means connecting said second input connection of the second of said phase responsive control means to said output terminals of said phase shifting apparatus.

11. In combination, a transmission line having first and second and third conductors energized from a polyphase alternating potential source for transmitting electrical energy in a predetermined direction, the energization of said conductors normally being such that a first voltage between said second and said first conductors may be represented by a positive first potential vector, that a second voltage between said third and said second conductors may be represented by a positive second potential vector lagging said first vector by 120 electrical degrees and that a third voltage between said first and said third conductors may be represented by a positive third potential vector lagging said second vector by 120 electrical degrees, the current in said first and second and third conductors being representable by positive fourth and fifth and sixth current vectors having a phase angle of not over ninety degrees from the said first and second and third vectors respectively when said energy is flowing in said predetermined direction, first and second and third pairs of control terminals, each said pair of control terminals having a first and second terminal, potential energized means operatively connected to said transmission line and deriving therefrom first and third alternating electrical quantities of a fixed phase angle with respect to said first and third vectors, said first and third quantities being in phase when the phase angle thereof is said fixed angle with respect to said first and third voltages respectively and being out-of-phase when the phase angle thereof is 180 from said fixed angle, current energized means deriving from said transmission line fourth and fifth and sixth alternating electrical quantities of a predetermined phase angle with respect to said fourth and fifth and sixth vectors respectively, said fourth and fifth and sixth quantities being in phase when the phase angle thereof with respect to said currents in said first and second and third conductors respectively is said predetermined angle and being out of phase when the phase angle thereby is 180 from said predetermined angle, first and second summing devices, each said summing device having first and second pairs of input terminals and first and second output terminals, and means for vectorially summing the alternating quantities applied to its said pairs of input terminals to produce a first summed quantity, each said summing device further having means including phase shifting apparatus for supplying said first summed quantity to its said output terminals as a compensating quantity phase shifted from the phase of said first summed quantity, first and second and third potential quantity terminals, means applying said first quantity between said second and said first potential quantity terminals and applying said third quantity between said third and said second potential quantity terminals whereby the angles between the vector which represent said potential quantities at said potential quantity terminals is the same as the angle between the vectors representing the voltages from which said first and third potential quantities are derived, circuit means connecting said first potential quantity terminal to a first terminal of said first pair of control terminals through said output terminals of said first summing device, circuit means connecting said second potential quantity terminal to the second terminal of said first pair of control terminals whereby said first pair of control terminals is energized with a first alternating control quantity which is,

the vector sum of said inphase component of said first quantity and said compensating quantity of said first summing device, means connecting said current energized means to said pairs of input terminals of said first summing device for energization of said-first pair thereof with the inphase component of said fourth quantity and for energization of said second pair thereof with the out-of-phase component of said fifth quantity, circuit means connecting said second potential quantity terminal to a first terminal of said second pair of control terminals, circuit means connecting said third potential quantity terminal to the second terminal of said second pair of control terminals through said output terminals of said second summing device whereby said second pair of input terminals is energized with a second alternating control quantity which is the vector sum of said inphase component of said third quantity and said compensating quantity of said second summing device, means connecting said current energized means to said pairs of input terminals of said second summing device for energization of said first pair thereof with the inphase component of said sixth quantity and for energization of said second pair thereof with the out-of-phase component of said fifth quantity, circuit means connecting said first potential quantity to said third pair of control terminals and including phase shifting means for shifting the phase of the quantity at said third pair of control terminals such that the vector representation of said last named quantity when taken in a direction from a first to a second terminal of said third pair of control terminals is leading with respect to said first quantity, and breaker trip means connected to said pairs of control terminals, said trip means being rendered effective to trip a breaker whenever the phase of the quantity between said first and second terminals of said first pair of contact terminals is leading with respect to the quantity between said first and second terminals of at least one of said second and said third pairs of control terminals.

12. In a relaying system, a first input generating network having a first input connection and a second input connection and an output connection, said network including means to energize said output connection with an output electrical quantity in response to the application of electrical input quantities to said input connections and to phase said output quantity with respect to one of said input quantities as a function of the relative phasing of said input quantities, a second signal generating network having at least one input connection for energization with an input electrical quantity and an output connection, said second network including means to energize its said output connection with an output quantity of a phase determined at least in part by the said input quantity which is supplied to said input connection of said second network, a pair of output terminals, a pair of power supply terminals, a switching network connecting said pairs of terminals and having first and second operating conditions in which said supply terminals are effective to cause energization and de-energization of said output terminals respectively, means operatively connecting said switching network to said output connection of one of said generating networks for transferring said switching network from its said second to its said first condition in accordance with the phase of said output quantity of said one generating network, said switching network having a third operating condition in which said switching network is rendered inefiective to energize its said output terminals in response to said one generating network, and means operatively connecting said switching network to the other of said generating networks whereby said other network is effective to place said switching network in its said third condition.

13. The combination ofclaim 12 in which said switching network is rendered in its said third condition solely when the phase angle between said output quantities when taken with respect to a given one of said output quantities lies within a given phase quadrant.

14. In a relaying system, first and second signal generators, providing first and second pulsating electrical output quantities at first and second output connections respectively in response to the application of input quantities applied to said generators, said generators including means to phase the pulse of said output quantity of one of said generators in leading and lagging time relation with respect to the other of said generators in response to a change in the relative phases of said input quantities, a pair of output terminals, a switching network connected to said terminals and having first and second input connections, means connecting said first input connection to said first output connection, means connecting said second input connection to said second output connection, said switching network including means to energize said output terminals solely when the phase of said output quantity. of said one generator is phased in one of said time relations and ineffective to energize said output terminals when the phase of said output quantity of said one generator is phased in the other of said time relations.

15. The combination ofclaim 14 in which said switching network is provided with means energized in timed relation with said output terminals and effective to render said switching network ineffective to deenergize said output terminals throughout the pulse period of the leading one of said electrical quantities when said phase is in said one time relation.

16. The combination ofclaim 14 in which there is provided a normally conductive shunting circuit connected between said output terminals to prevent energization thereof by said switching network, and means responsive to the energized condition of said other generator.

17. In a relaying system, an operate signal generator, a polarizing signal generator, each said generator providing spaced pulse-like electrical output quantities in response to alternating electrical quantities supplied thereto, a pair of input terminals, a pair of output terminals, first and second and third electric switches each said switch having a main circuit and a control circuit for controlling at least the initiation of current flow through its said main circuit, first means interconnecting said input terminals and including in series connection said main circuit of said first switch and said load terminals, means connecting said control circuit of said first switch to said operate generator for rendering conductive said main circuit of said first switch by said output quantity of said operate generator, second means interconnecting said input terminals and including said main circuit of said second switch, means connecting said control circuit of said second switch to said polarizing generator for rendering conductive said main circuit of said second switch by said output quantity of said polarizing generator, said second means having an impedance which is sufiiciently low whereby the voltage drop thereacross, when said main circuit of second switch is conducting, is insufficient to provide a useable potential across said load terminals when said main circuit of said second switch is conductive, a third means connected in shunt with said control circuit of said second switch and including said main circuit of said third switch whereby said polarizing generator is ineffective to energize said control circuit of said second switch when said main circuit of said third switch is conductive, and means connecting said control circuit of said third switch to said main circuit of said first switch whereby conduction of said main circuit of said first swi-tch initiates conduction of said main circuit of said third switch.

18. In a relaying system, an operate signal generator, a polarizing signal generator, said signal generators hav-- ing input means adapted to be energized by alternating input quantities, each said generator having output connections energized with an alternating output quantity as a consequence of the energization of its said input means, the phase relationship of said output quantities being determined by the phase relationship of said input quantities, first and second impedance devices connected to said operate and said polarizing generators respectively for energization by said output quantities, each said device having first and second end terminals and an intermediate terminal, a pair of input terminals, a pair of load terminals, circuit means connecting a first of said input terminals to a first of said output terminals a plurality of switches, each said switch having a main circuit and a control circuit, means connecting the second of said input terminals to the second of said output terminals and including said main circuits of a first and of a second of said switches, said main circuits of said first and second switches being connected in parallel, means connecting said second output terminal to said first output terminal and including said main circuits of a third and of a fourth of said switches, said main circuits of said third and of said fourth switches being connected in parallel, means connecting said control circuits of said first and and of said second switches between said intermediate terminal and said first end terminal and between said intermediate terminal and said second end terminal of said first impedance device respectively whereby said main circuits of said first and second switches are sequentially rendered conducting in alternate relationship by said operate generator, means connecting said control circuits of said third and of said fourth switches between said intermediate terminal and said first end terminal and between said intermediate terminal and said second end terminal of said second impedance device respectively whereby said main circuits of said third and fourth switches are sequentially rendered conducting in alternate relationship by said polarizing generator.

19. In a relaying system, an operate signal generator, a polarizing signal generator, said signal generators having input means adapted to be energized by alternating input quantities, each said generator having output connections energized with an alternating output quantity as a consequence of the energization of its said input means, the phase relationship of said output quantities being determined by the phase relationshi of said input quantities, first and second impedance devices connected to said operate and said polarizing generators respectively for energization by said output quantities, each said device having first and second end terminals and an intermediate terminal, a pair of input terminals, a pair of load terminals, circuit means connecting a first of said input terminals to a first of said output terminals a plurality of switches, each said switch having a main circuit and a control circuit, means connecting the second of said input terminals to the second of said output terminals and including said main circuits of a first and of a second of said switches, said main circuits of said first and second switches being connected in parallel, means connecting said second output terminal to said first output terminal and including said main circuits of a third and of a fourth of said switches, said main circuits of said third and of said fourth switches being connected in parallel, means connecting said control circuits of said first and of said second switches between said intermediate terminal and said first end terminal and between said intermediate terminal and said second end terminal of said first impedance device respectively whereby said main circuits of said first and second switches are sequentially rendered conducting in alternate relationship by said operate generator, means connecting said control circuits of said third and of said fourth switches between said intermediate terminal and said first end terminal and between said intermediate terminal and said second end terminal of said second impedance device respectively whereby said main circuits of said third and fourth switches are sequentially rendered conducting in alternate relationship by said polarizing generator, means connected to said control circuits of said third and of said fourth switches and including said main circuits of a fifth and of a sixth of said switches, means connecting said control circuits of said fifth and of said sixth switches to said main circuits of said first and of said second switches respectively, said fifth and said sixth switches being effective as a consequence of the conduction of said main circuits of said first and of said second switch to render said polarizing 21 generator ineffective to render conductive said main circuits of said third and of said fourth switches.

20. The combination of claim 19 in which said main circuit of a sixth of said switches is connected between said output terminals and said control circuit of said sixth switch is operatively connected to said polarizing generator, said main circuit of said sixth switch being normally conductive to prevent energization of said load terminals in the absence of an output signal from said polarizing generator and being rendered non-conductive by said output quantity of said polarizing generator.

21. In a network, first and second alternating polarity electrical quantity sources, a unidirectional directional potential source, a load, a plurality of electric valves, each said valve having a main circuit and a control circuit, first circuit means connecting said load to said unidirectional source and including said main circuit of a first of said valves, means connecting said control circuit of said first valve to said first alternating source whereby said main circuit of said first valve is periodically rendered conducting in timed relation to the alternations of said alternating quantity of said first source, means connecting said main circuit of a second of said valves in series circuit with said main circuit of said first valve and in shunt with said load, means connecting said control circuit of said second valve to said second alternating source whereby said main circuit of said second valve is periodically rendered conducting in timed relation to the alternations of said alternating quantity of said second source, means connecting said main circuit of a third of said valves in said first circuit means, said third valve being effective in a first condition to render said first valve ineffective to energize said load and effective in a second condition to render said first and second valves effective to control the energization of said load, means connecting said control circuit of said third valve to said second source whereby said third valve is held in its said first condition in the absence of said electrical quantity of said second source and held in its said second condition in the presence of said electrical quantity of said second source, means limiting the current flow through said main circuit of said first valve.

22. The combination of claim 21 in which there is a fourth of said valves, means connecting said main circuit of said fourth valve to said control circuit of said second valve, said fourth valve being effective in a first condition to render said control circuit of said second valve effective to respond to said alternating quantity of said second source, said fourth valve being effective in a second condition to render said control circuit of said second valve ineffective to respond to said alternating quantity of said second source, and means connecting said control circuit of said fourth valve to said first valve whereby said fourth valve is transferred from its said first to its said second condition in timed relation to the rendering of said main circuit of said first valve conductive.

23. The combination of claim 21 in which there is a fourth of said valves, means connecting said main circuit of said fourth valve to said control circuit of said second valve, said fourth valve being effective in a first condition to render said control circuit of said second valve effective to respond to said alternating quantity of said second source, said fourth valve being effective in a second condition to render said control circuit of said second valve ineffective to respond to said alternating quantity of said second source, and means connecting said control circuit of said fourth valve .to said first valve whereby said fourth valve is transferred from its said first to its said second condition in timed relation to the rendering said main circuit of said first valve conductive, at least said first valve being of the continuous control type in which current flow through its said main circuit is interrupted as well as initiated by its said control circuit, at least said second valve being of the discontinuous control type in which the initiation of current flow through its said main 22 circuit is controlled by its said control circuit but its saidcontrol circuit is ineffective to interrupt current flow through its said main circuit.

24. In a network, first and second alternating polarity electrical quantity sources, a unidirectional directional potential source, a load, a plurality of electric valves, each said valve having a main circuit and a control circuit, first circuit means connecting said load to said unidirectional source and including said main circuit of a first of said valves, means connecting said control circuit of said first valve to said first alternating source whereby said main circuit of said first valve is periodically rendered conducting in 'timed relation to the alternations of said alternating quantity of said first source, means connecting said main circuit of a second of said valves in series circuit with said main circuit of said first valve and in shunt with said load, means connecting said control circuit of said second valve to said second alternating source whereby said main circuit of said second valve is periodically rendered conducting in timed relation to the alternations of said alternating quantity of said second source, a third of said valves, means connecting said main circuit of said third valve to said control circuit of said second valve, said third valve being effective in a first condition to render said control circuit of said second valve effective to respond to said alternating quantity of said second source, said third valve being effective in a second condition to render said control circuit of said second valve ineffective to respond to said alternating quantity of said second source, and means connecting said control circuit of said third valve tosaid first valve whereby said third valve is transferred from its said first to its said second condition in timed relation to the rendering of said main circuit of said first valve conductive.

25. In an apparatus for use in protecting a three phase electrical transmission line, first and second and third potential supplying terminals adapted to be engaged with a potential device respectively from the first and second and third line conductors of said transmission line and proportioned to the said line potentials first and second and third current supply circuits adapted to be energized Wlth a current derived respectively from the first and second and third line conductors of said transmission line and proportioned to the said line currents, an operate signal generator having input terminals and output terminals and a first signal forming network interconnecting its said input ternnnals to its said output terminals, said signal network comprising a mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals and additional winding means, said additional winding means being connected to said first and second current supply circuits to energize said inductance device with a current quantity equal to the difference in the current magnitudes in said first and said second current supply circuits, an electrical conducting path connecting the other of said input terminals to the other of said output terminals, a transformer having a first winding connected between said output terminals and a second winding having end terminals and an intermediate terminal, means connecting said input terminals of said generator to said first and said second potential supplying terminals, first and second switch devices each said device having a main circuit and a control circuit for initiating and terminating current flow through its associated said main circuit, a pair of direct potential energized buses, an output circuit, first and second impedance devices, each saidimpedance device having first and second terminals, means connecting said first terminal of said first impedance device to one of said buses and including said main circuit of said first valve, means connecting said first terminal, said second impedance device to said one bus and including said main circuit of said second valve, means connecting said second terminals of said impedance devices through said output circuit to the other of said buses, means connecting said control circuit of said first valve between said intermediate terminal and one of said end terminals and connecting said control circuit of said second valve between said intermediate terminal and the other of said end terminals whereby said first and second valves are rendered conducting in alternating relation, a first polarizing signal generator having a pair of input terminals connected to a pair of output terminals through a phase shifting circuit and a resonant circuit, said resonant circuit including capacitive and inductive reactance tuned to resonate at the frequency of said protected three phase line, means connecting said output terminals of said polarizing generator to said first and said second potential supplying terminals, a second transformer having a primary winding connected to said output terminals of said polarizing generator and a secondary winding having end terminals and an intermediate terminal, third and fourth switch devices, each said third and fourth switch devices being a main circuit and a control circuit for initiating current flow through its said main circuit, means connecting said control circuit of said third valve between said intermediate terminal and one of said end terminals of said secondary winding of said second transformer and connecting said control circuit of said fourth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said second transformer, circuit means connecting said first terminal of said first impedance device to said other bus and including said main circuit of said third valve, and circuit means connecting said first terminal of said second impedance device to said other bus and including said main circuit of said fourth valve.

26; In an apparatus for use in protecting a three phase electrical transmission line, first and second and third potential supplying terminals adapted to be engaged with a potential device respectively from the first and second and third line conductors of said transmission line and proportioned to the said line potentials first and second and third current supply circuits adapted to be energized with a current derived respectively from'the first and second and third line conductors of said transmission line and proportioned to the said line currents, an operate signal generator having input terminals and output terminals and a first signal forming network interconnecting its said input terminals to its said output terminals, said signal network comprising a mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals and additional winding means, said additional winding means being connected to said first and second current supply circuits to energize said inductance device with a current quantity equal to the difference in the current magnitudes in said first and said second current supply circuits, an electrical conducting path connecting the other of said input terminals to the other of said output terminals, a transformer having a first winding connected between said output terminals and a second winding having end terminals and an intermediate terminal, means connecting said input terminals of said generator to said first and said second potential supplying terminals, first and second switch devices each said device having a main circuit and a control circuit for initiating and terminating current flow through its associated said main circuit, a pair of direct potential energized buses, an output circuit, first and'second impedance devices, each said impedance device having'first and second terminals, means connecting said first terminal of said first impedance device to one of said buses and including said main circuit of said first valve, means connecting said first terminal, said second impedance device to said one bus and including said main circuit of said second valve, means connecting said second terminals of said impedance devices through said output circuit to the other of said buses, means connecting said control circuit of said first valve between said intermediate terminal and one of said end terminals and connecting said control circuit of said second valve between said intermediate terminal and the other of said end terminals whereby said first and second valves are rendered conducting in alternating relation, a first polarizing signal generator having a pair of input terminals connected to a pair of'output terminals through a phase shifting circuit and a resonant circuit, said resonant circuit including capacitive and inductive reactance tuned to resonate at the frequency of said protected three phase line, means connecting said output terminals of said polarizing generator to said first and said second potential supplying terminals, a second transformer having a primary winding connected to said output terminals of said polarizing generator and a secondary winding having end terminals and an intermediate terminal, third and fourth switch devices, each said third and fourth switch devices being a main circuit and a control'circuit for initiating current flow through its said main circuit, means connecting said control circuit of said third valve between said intermediate terminal and one of said end terminals of said secondary winding of said second transformer and connecting said control circuit of said fourth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said second transformer, circuit means connecting said first terminal of said first impedance device to said other bus and including said main circuit of said third valve, and circuit means connecting said first terminal of said second impedance device to said other bus and including said main circuit of said fourth valve, a fifth value having a main circuit for initiating current fiow through its said main circuit, circuit means connecting said main circuit of said fifth value in shunt with said output circuit, and circuit means connected to said contact circuit of said fifth valve and to a pair of said potential supplying terminals, said last named circuit means including means for maintaining said main circuit of said fifth valve nonconducting when said pair of potential supplying terminals are energized.

27. In an apparatus for use in protecting a three phase electrical transmission line, first and second and third potential supplying terminals adapted to be engaged with a potential device respectively from the first and second and third line conductors of said transmission line and proportioned to the said line potentials first and second and third current supply circuits adapted to be energized with a current derived respectively from the first and second and third line conductors of said transmission line and proportioned to the said line currents, an operate signal generator having input terminals and output terminals and a first signal forming network interconnecting its said input terminals to its said output terminals, said signal network comprising a mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals and additional winding means, said additional winding means being connected to said first and second current supply circuits to energize said inductance device with a current quantity equal to the difference in the current magnitudes in said first and said second current supply circuits, an electrical conducting path connecting the other of said input terminals to the other of said output terminals, a transformer having a first winding connected between said output terminals and a second winding having end terminals and an intermediate terminal, means connecting said input terminals of said generator to said first and said second potential supplying terminals, first and second switch devices each said device having a main circuit and a control circuit for initiating and terminating current flow through its associated said main circuit, a pair of direct potential energized buses, an output circuit, first and second impedance devices, each said impedance device having first and second terminals, means connecting said first terminal of said first impedance device to one of said buses and including said main circuit of said first valve, means connecting said first terminal, said second impedance device to said one bus and including said main circuit of said second valve, means connecting said second terminals of said impedance devices through said output circuit to the other of said buses, means connecting said control circuit of said first valve between said intermediate terminal and one of said end terminals and connecting said control circuit of said second valve between said intermediate terminal and the other of said end terminals whereby said first and second valves are rendered conducting in alternating relation, a first polarizing signal generator having a pair of input terminals connected to a pair of output terminals through a phase shifting circuit and a resonant circuit, said resonant circuit including capacitive and inductive reactance tuned to resonate at the frequency of said protected three phase line, means connecting said output terminals of said polarizing generator to said first and second potential supplying terminals, a second transformer having a primary winding connected to said output terminals of said polarizing generator and a secondary winding having end terminals and an intermediate terminal, third and fourth switch devices, each said third and fourth switch devices being a main circuit and a control circuit for initiating current flow through its said main circuit, means connecting said control circuit of said third valve between said intermediate terminal and one of said end terminals of said secondary .Winding of said second transformer and connecting said control circuit of said fourth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said second transformer, circuit means connecting said first terminal of said first impedance device to said other bus and including said main circuit of said third valve, and circuit means connecting said first terminal of said second impedance device to said other bus and including said main circuit of said fourth valve, a second polarizing generator having input terminals and output terminals and a second signal forming interconnecting its said input terminals to its said output terminals, said second signal forming networks comprising a second mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals of said second polarizing generator and additional winding means, said additional winding means being connected to said second and said third current supplying circuits to energize said second mutual inductance device with a current quantity equal to the difference in the current magnitude in said second and said third current supply circuits, an electrical conducting path connecting the other of said input terminals of said second polarizing generator to the other of said output terminals of said second polarizing generator, a third transformer having a primary winding connected between said output terminals of said second polarizing generator and a secondary winding having end terminals and an intermediate terminal, a fifth and a sixth valve, each said fifth and said sixth valve having a mam circuit and a contact circuit for initiating the flow of current through its said main circuit, circuit means connecting said second terminal of said first impedance to said other bus and including said main circuit of said fourth valve, circuit means connecting said second terminal of said second impedance to said other bus and including said main circuit of said fifth valve, means connecting said control circuit of said fourth valve between said intermediate terminal and one of said end terminals of said secondary winding of said third transformer, means connecting said control circuit of said sixth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said third transformer.

28. In an apparatus for use in protecting a three phase electrical transmission line, first and second and third potential supplying terminals adapted to be engaged with a potential device respectively from the first and second and third line conductors of said transmission line and proportioned to the said line potentials first and second and third current supply circuits adapted to be energized with a current derived respectively from the first and second and third line conductors of said transmission line and proportioned to the said line currents, an operate signal generator having input terminals and output terminals and a first signal forming network interconnecting its said input terminals to its said output terminals, said signal network comprising a mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals and addi tional winding means, said additional winding means being connected to said first and second current supply circuits to energize said inductance device with a current quantity equal to the difference in the current magnitudes in said first and said second current supply circuits, an electrical conducting path connecting the other of said input terminals to the other of said output terminals, a transformer having a first winding connected between said output terminals and a second winding having end terminals and an intermediate terminal, means connecting said input terminals of said generator to said first and said second potential supplying terminals, first and second switch devices each said device having a main circuit and a control circuit for initiating and terminating current flow through its associated said main circuit, a pair of direct potential energized buses, an output circuit, first and second impedance devices, each said impedance device having first and second terminals, means connecting said first terminal of said first impedance device to one of said buses and including said main circuit of said first valve, means connecting said first terminal, said second impedance device to said one bus and including said main circuit of said second valve, means connecting said second terminals of said impedance devices through said output circuit to the other of said buses, means connecting said control circuit of said first valve between said intermediate terminal and one of said end terminals and connecting said control circuit of said second valve between said intermediate terminal and the other of said end terminals whereby said first and second valves are rendered conducting in alternating relating a first polarizing signal generator having a pair of input terminals connected to a pair of output terminals through a phase shifting circuit and a resonant circuit, said resonant circuit including capacitive and inductive reactance tuned to resonate at the frequency of said protected three phase line, means connecting said output terminals of said polarizing generator to said first and said second potential supplying terminals, a second transformer having a primary winding connected to said output terminals of said polarizing generator and a secondary winding having end terminals and an intermediate terminal, third and fourth switch devices, each said third and fourth switch devices being a main circuit and a control circuit for initiating current flow through its said main circuit, means connecting said control circuit of said third valve between said intermediate terminal and one of said end terminals of said secondary winding of said second transformer and connecting said control circuit of said fourth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said second transformer, circuit means connecting said first terminal of said first impedance device to said other bus and including said main circuit of said third valve, and circuit means connecting said first terminal of said second impedance device to said other bus and including said main circuit of said fourth valve, a second polarizing generator having input terminals and output terminals and a second signal forming interconnecting its said input terminals to its said output terminals, said second signal forming networks comprising a second mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals of said second polarizing generator and additional Winding means, said additional winding means being connected to said second and said third current supplying circuits to energize said second mutual inductance device with a current quantity equal to the difference in the current magnitude in said second and said third current supply circuits, an electrical conducting path connecting the other of said input terminals of said second polarizing generator to the other of said output terminals of said second polarizing generator, a third transformer having a primary winding connected between said output terminals of said second polarizing generator and a secondary winding having end terminals and an intermediate terminal, a fifth and a sixth valve, each said fifth and said sixth valve having a main circuit and a contact circuit for initiating the flow of current through its said main circuit, circuit means connecting said second terminal of said first impedance to said other bus and including said main circuit of said fourth valve, circuit means connecting said second terminal of said second impedance to said other bus and including said main circuit of said fifth valve, means connecting said control circuit of said fourth valve between said intermediate terminal and one of said end terminals of said secondary winding of said third transformer, means connecting said control circuit of said sixth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said third transformer, a seventh and an eighth valve, each said seventh and said eighth valve having a main circuit and a contact circuit for initiating the flow of current through its said main circuit, circuit means connecting said main circuit of said seventh valve in shunt with said main circuit of said third valve and said main circuit of said eighth valve in shunt with said main circuit of said fourth valve, circuit means connecting said control circuit of said seventh valve in circuit with said main circuit of said first valve and said control circuit of said eighth valve in circuit with said main circuit of said second valve.

29. In an apparatus for use in protecting a three phase electrical transmission line, first and second and third potential supplying terminals adapted to be engaged with a potential device respectively from the first and second and third line conductors of said transmission line and proportioned to the said line potentials first and second and third current supply circuits adapted to be energized with a current derived respectively from the first and second and third line conductors of said transmission line and proportioned to the said line currents, an operate signal generator having input terminals and output terminals and a first signal forming network interconnecting its said input terminals to its said output terminals, said signal network comprising a mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals and additional winding means, said additional winding means being connected to said first and second current supply circuits to energize said inductance device with a current quantity equal to the difference in the current magnitudes in said first and said second current supply circuits, an electrical conducting path connecting the other of said input terminals to the other of said output terminals, a transformer having a first winding connected between said output terminals and a second winding having end terminals and an intermediate terminal, means connecting said input terminals of said generator to said first and said second potential supplying terminals, first and second switch devices each said device having a main circuit and a control circuit for initiating and terminating current fiow through its associated said main circuit, a pair of direct potential energized buses, an output circuit, first and second impedance devices, each said impedance device having first and second terminals, means connecting said first terminal of said first impedance device to one of said buses and including said main circuit of said first value, means connecting said first terminal, said second impedance device to said one bus and including said main circuit of said second value, means connecting said second terminals of said impedance devices through said output circuit to the other of said buses, means connecting said control circuit of said first valve between said intermediate terminal and one of said end terminals and connecting said control circuit of said second valve between said intermediate terminal and the other of said end terminals whereby said first and second valves are rendered conducting in alternating relation, a first polarizing signal generator having a pair of input terminals connected to a pair of output terminals through a phase shifting circuit and a resonant circuit, said resonant circuit including capacitive and inductive reactance tuned to resonate at the frequency of said protected three phase line, means connecting said output terminals of said polarizing generator to said first and said second potential supplying terminals, a second transformer having a primary winding connected to said output terminals of said polarizing generator and a secondary winding having end terminals and an intermediate terminal, third and fourth switch devices, each said third and fourth switch devices being a main circuit and a control circuit for initiating current flow through its said main circuit, means connecting said control circuit of said third valve between said intermediate terminal and one of said end terminals of said secondary winding of said second transformer and connecting said control circuit of said fourth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said second transformer, circuit means connecting said first terminal of said first impedance device to said other bus and including said main circuit of said third valve, and circuit means connecting said first terminal of said second impedance device to said other bus and including said main circuit of said fourth valve, a second polarizing generator having input terminals and output terminals and a second signal forming interconnecting its said input terminals to its said output terminals, said second signal forming networks comprising a second mutual inductance device having a first winding connected between one of said input terminals and one of said output terminals of said second polarizing generator and additional winding means, said additional winding means being connected to said second and said third current supplying circuits to energize said second mutual inductance device with a current quantity equal to the difference in the current magnitude in said second and said third current supply circuits, an electrical conducting path connecting the other of said input terminals of said second polarizing generator to the other of said output terminals of said second polarizing generator, a third transformer having a primary winding connected between said output terminals of said second polarizing generator and a secondary winding having end terminals and an intermediate terminal, a fifth and a sixth valve, each said fifth and said sixth valve having a main circuit and a contact circuit for initiating the flow of current through its said main circuit, circuit means connecting said second terminal of said first impedance to said other bus and including said main circuit of said fourth valve, circuit means connecting said second terminal of said second impedance to said other bus and including said main circuit of said fifth valve, means connecting said control circuit of said fourth valve between said intermediate terminal and one of said end terminals of said secondary winding of said third transformer, means connecting said control circuit of said sixth valve between said intermediate terminal and the other of said end terminals of said secondary winding of said third transformer, a seventh and an eighth valve, each said seventh and said eighth valve having a main circuit and a contact circuit for initiating the flow of current through its said main circuit, circuit means connecting said main circuit of said seventh valve in shunt with said main circuit of said third valve and said main circuit of said eighth valve in shunt with said main circuit of said fourth valve, circuit means connecting said control circuit of said seventh valve in circuit with said main circuit of said first valve 29 30 and said control circuit of said eighth valve in circuit with References Cited said main circuit of said second valve, a ninth valve having UNITED STATES PATENTS a main circuit and a control circuit for initiating current flow through its said main circuit, circuit means connect- 3144586 8/1964 GamPale 317 36 ing said main circuit of said ninth valve in shunt with said 5 3'192442 6/1965 Wanmton 317 36 output circuit, and circuit means connected to said con- 3,201,651 8/1965 Calhoun 317' 36 trol circuit of said ninth valve and to a pair of said 3'303390 2/1967 Sonnemann 317-36 potential supplying terminals, said last named circuit means including means for maintaining said main circuit MILTON O. HIRSHFIELD, Primary Examiner. of said ninth valve nonconducting when said pair of 10 potential supplying terminals are energized. R LUPO, Assislam Examiner-

Claims (1)

1. IN A RELAYING SYSTEM FOR A THREE PHASE NETWORK, A FIRST PLURALITY OF INPUT TERMINALS SUPPLYING A THREE PHASE ELECTRICAL QUANTITY WHICH IS PROPORTIONAL TO THE POTENTIAL OF A THREE PHASE NETWORK FROM WHICH SAID FIRST TERMINALS ARE ENERGIZED, A SECOND PULRALITY OF INPUT TERMINALS SUPPLYING A THREE PHASE ELECTRICAL QUANTITY WHICH IS PROPORTIONAL TO THE CURRENT FLOWING IN A THREE PHASE NETWORK FROM WHICH SAID SECOND TERMINALS ARE ENERGIZED, FIRST AND SECOND AND THIRD PAIRS OF OUTPUT TERMINALS, FIRST AND SECOND COMPENSATORS, EACH SAID COMPENSATOR INCLUDING INPUT MEANS AND OUTPUT MEANS AND EFFECTIVE TO ENERGIZE ITS SAID OUTPUT MEANS WITH A COMPENSATING VECTOR QUANTITY WHICH IS THE VECTOR SUM OF ELECTRICAL QUANTITIES SUPPLIED TO ITS SAID INPUT MEANS, EACH SAID COMPENSATOR FURTHER INCLUDING MEANS TO SHIFT THE PHASE OF ITS SAID COMPENSATING VECTOR QUANTITY WITH RESPECT TO SAID VECTOR SUM OF SAID ELECTRICAL QUANTITIES SUPPLIED THERETO, FIRST CIRCUIT MEANS CONNECTING A FIRST PAIR OF SAID FIRST INPUT TERMINALS TO SAID FIRST PAIR OF OUTPUT TERMINALS AND INCLUDING SAID OUTPUT MEANS OF SAID FIRST COMPENSATOR WHEREBY SAID FIRST PAIR OF OUTPUT TERMINALS IS ENERGIZED BY THE VECTOR SUM OF THE SAID QUANTITIES WHICH ARE SUPPLIED TO SAID FIRST CIRCUIT MEANS BY SAID FIRST PAIR OF INPUT TERMINALS AND SAID FIRST COMPENSATOR, A SECOND CIRCUIT MEANS CONNECTING A SECOND PAIR OF SAID FIRST INPUT TERMINALS TO SAID SECOND PAIR OF OUTPUT TERMINALS AND INCLUDING SAID OUTPUT MEANS OF SAID SECOND COMPENSATOR WHEREBY SAID SECOND PAIR OF OUTPUT TERMINALS ARE ENERGIZED BY THE VECTOR SUM OF THE SAID QUANTITIES WHICH ARE SUPPLIED TO SAID SECOND CIRCUIT MEANS BY SAID SECOND PAIR OF INPUT TERMINALS AND SAID SECOND COMPENSATOR, A PHASE SHIFTING CIRCUIT, A THIRD CIRCUIT MEANS CONNECTING SAID FIRST PAIR OF INPUT TERMINALS TO SAID THIRD PAIR OF OUTPUT TERMINALS AND INCLUDING SAID PHASE SHIFTING CIRCUIT WHEREBY THE PHASE OF THE SAID QUANTITY WHICH IS SUPPLIED TO SAID THIRD PAIR OF OUTPUT TERMINALS MAY BE PHASE SHIFTED WITH RESPECT TO THE PHASE OF THE SAID QUANTITY SUPPLIED TO SAID THIRD CIRCUIT MEANS FROM SAID FIRST PAIR OF INPUT TERMINALS, MEANS CONNECTING SAID INPUT MEANS OF SAID FIRST COMPENSATOR TO A FIRST GROUP OF TERMINALS OF SAID SECOND PLURALITY OF TERMINALS TO SUPPLY A FIRST CURRENT COMPENSATING QUANTITY TO SAID FIRST COMPENSATOR WHICH IS REPRESNTATIVE OF THE DIFFERENCE BETWEEN A FIRST PHASE QUANTITY AND A SECOND PHASE QUANTITY OF SAID THREE PHASE QUANTITY SUPPLIED BY SAID SECOND PLURALITY OF INPUT TERMINALS, MEANS CONNECTING SAID INPUT MEANS OF SAID SECOND COMPENSATOR TO A SECOND GROUP OF TERMINALS OF SAID SECOND PLURALITY OF TERMINALS TO SUPPLY A SECOND CURRENT COMPENSATING QUANTITY TO SAID SECOND COMPENSATOR WHICH IS REPRESENTATIVE OF THE DIFFERENCE BETWEEN TWO PHASE QUANTITIES OF SAID THREE PHASE QUANTITY SUPPLIED BY SAID SECOND PLURALITY OF INPUT TERMINALS, AND A PHASE SENSITIVE CONTROL CIRCUIT CONNECTED TO SAID PAIRS OF OUTPUT TERMINALS AND EFFECTIVE WHEN THE PAHSE OF SAID QUANTITY OF A PREDETERMINED PAIR OF SAID OUTPUT TERMINALS IS LEADING IN PHASE RELATIONSHIP WITH THE PHASE OF EITHER OF SAID QUANTITIES OF THE OTHER TWO OF SAID PARIS OF SAID OUTPUT TERMINALS.

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