CN110506376B - Electrical switching apparatus - Google Patents

Abstract

An electrical switching apparatus (1) comprising: at least one semiconductor switch (2, 3) arranged in the circuit (4, 5); electrical measuring means (7, 8, 9, 24); a control device (6) which evaluates the measured values determined by the measuring devices (7, 8, 9, 24) and is designed to actuate the semiconductor switches (2, 3), wherein the control device (6) causes an automatically determined actuation of the semiconductor switches (2, 3) when a determined measured value is detected, wherein conditions for actuating the semiconductor switches (2, 3) can be transmitted to the control device (6) by means of an activation process via a data interface (10).

Description

Electrical switching apparatus

Technical Field

The present invention relates to an electrical switching apparatus.

Background

Protective devices are provided in electrical installations, which protect the devices, such as lines or consumers, against impermissible and dangerous operating conditions. For example, wire protection switches are used to protect wires from short circuit currents or long lasting overcurrents. The protection of the persons against dangerous contact voltages due to defective electrical devices is provided by means of a fault current switch, wherein the current flowing through the persons is detected and switched off when the value is low. For electric machines, motor protection switches are often used, which cause a switch-off in the event of a failure of one phase of the three-phase ac system, since the electric machine itself also runs in the remaining successive sequence after its start, but is thermally overloaded. However, the mentioned and other protective devices are not suitable for complying with the frequent switching of operation, so that switching devices, for example electromagnetically actuated relays, are also arranged in series with these protective devices. These switching devices, although designed for a large number of switching cycles, are not capable of interrupting short-circuit currents. Thus, at least one protection device and, if necessary, also a switching device is provided for each circuit. In the circuit for the socket, the switching device is not usually provided, but in the circuit for the motor, the switching device is practically always provided. The actuation of the protection and switching system can be effected manually or remotely force-actuated. In vehicles, for example rail vehicles, in particular, the space requirement for electrical protection and switching systems is now considerable due to the ever increasing demands on the electrical systems of the vehicles, so that it is desirable to move switch cabinets to areas which can only be accessed with difficulty. This makes the operation difficult, so that it is only possible to carry out the operation more in the workshop. However, the disadvantages of the conventional remotely controllable protection and switching devices, such as the large space requirement, make them unsuitable for use in vehicles.

Disclosure of Invention

The invention is therefore based on the task of: an electrical switching apparatus is described which is capable of performing a switching operation by remote control and of performing a protection function for an electrical device connected to the electrical switching apparatus.

This object is achieved by an electrical switching device according to the invention.

According to a basic idea of the invention, an electrical switching device is described, comprising: at least one semiconductor switch disposed in the circuit; an electrical measuring device; a control device for evaluating measured values determined by the measuring device, which control device is designed to actuate the semiconductor switch, wherein the control device, upon detection of a determined measured value, brings about an automatically determined actuation of the semiconductor switch, and wherein conditions for actuating the semiconductor switch can be transmitted to the control device by means of an activation process via a data interface.

The following advantages can be achieved thereby: it is possible to provide an electrical switching device which not only makes it possible to carry out an operational switching action but also provides protection for the electrical devices connected thereto, which here has a low installation space requirement and can be remotely controlled.

According to the invention, the switching device is formed by means of a semiconductor switch which can be operated without wear and can also switch high currents on and off. Such a switching device is suitable for operating-compliant switching, like an electromechanical contactor, but is not subject to wear in this case. The switching device according to the invention additionally comprises a control device and a measuring device for detecting electrical variables, in particular for the current currently flowing through the switching device and the current voltage. The measuring device for the current intensity can be based on different measuring principles. The current strength can be determined using a current converter or by the voltage drop over a resistance (shunt). The current measurement by the voltage drop across the resistor is very precise and without delay, but heat losses occur continuously. If this high accuracy is not required, for example if the current value is used only for protection purposes, the semiconductor switch itself can be used as a current sensor. In this case, the determination of the current intensity without additional measuring resistors is achieved by means of what is known as vce (sat) monitoring or monitoring of the on-state voltage vds (on). The measured variable determined in this way is transmitted to the control device, so that the control device can determine the shut-off criterion, for example, on the basis thereof. These cut-off criteria relate to electrical values, for example excessive currents due to switching devices, so that the function of a fuse or an electromagnetic safety automatic switch can be imitated. In this case, this function is simulated by means of a control logic circuit or a program control in the control device, so that, for example, the triggering characteristic of the electromagnetic safety automatic switch can be simulated electronically.

According to the invention, the switching device can be equipped with a defined switching or protection function within the framework of the start-up procedure, wherein the corresponding configuration is transferred via the data interface into the memory of the control logic. It is therefore possible to use switching devices which are structurally identical and have different functions, since the specification of the specific functionality of the switching device is only determined by the start-up procedure.

In this way, switching devices with different switching or protective properties can be realized, wherein only the limit values of the semiconductor switches used play a limiting role.

For example, the switching device according to the invention can implement all the usual electrical protection functions. The following functionalities can be achieved in particular:

a quick cut-off at the time of a short circuit,

a cut-off in the event of a continuous overload,

switching off during impermissible changes in the load current (an arc is also detected in the circuit without exceeding the maximum permissible current),

the protection of the fault current is carried out,

protection against over-or under-voltage,

switching off (motor protection) in the event of a single phase failure,

wherein all trigger curves can be realized.

Another advantage of the switching device according to the invention is that: all commonly used electrical switching functions can be realized. The following functionalities can be achieved in particular:

on and off in operation without wear,

soft start (e.g. for an electric motor or lamp),

the switch-on of the large capacitance,

wherein certain parameters (e.g. acceleration time, current limit) can be adjusted. In this case, the parameters are adjusted during the start-up process by transmitting configuration data to the control device, or the configuration data can be stored in the control device in an unchangeable manner.

According to the invention, the switching device is equipped with a data interface, so that, in addition to the data required for the start-up process being transmitted to the control device, data can also be transmitted from the control device to a connected data sink, for example a superordinate diagnostic system. Here, it is recommended that: the current measured value, for example the current flowing through the switching device, is transmitted as a data value.

In a further embodiment of the invention, values derived from these measured values, such as electrical power or electrical operation (energy), can be determined by the control device and transmitted to the connected data receiver via the data interface.

It is particularly advantageous: the current switching state of the semiconductor switches is transmitted to the data interface by the control device, since this allows a higher-level control device, for example a higher-level diagnostic system, a vehicle control device or the like, to detect the current state of the electrical system and to present this state to the operator in a suitable form if necessary.

In a further embodiment of the invention, it is recommended that: the approach to the limit value of the electrical measured variable has been output as an alarm via a data interface. For example, if a fault current is detected, but the value of the fault current has not reached the limit value that caused the shut-off, an alarm can be issued.

A preferred embodiment of the invention provides that: the trigger condition that has caused the automatic switching action is output via the data interface. In this way, the superordinate control unit can, for example, further process the respective trigger cause (e.g. short circuit) and simplify targeted maintenance or repair. Another advantage is that: under certain conditions, the switch should not be immediately reconnected without clearing the trigger fault. For example, a reconnection (manual or automatic) of the electrical circuit of the motor after a triggering due to a short circuit or a fault current is disadvantageous. A preferred embodiment of the invention provides that: the control device automatically switches the semiconductor switch back on after an automatically determined switching-off process of the semiconductor switch. For this purpose, during the start-up of the switching device, those conditions in which an automatic reconnection is permitted should be transmitted via the data interface.

In a further embodiment of the invention, it is recommended that: at least one electromechanically actuable switching element is arranged in the circuit, which switching element can be actuated by the control device. In this way, the consumers attended by the switching device can be galvanically isolated from the energy supply device, so that it is possible to work on the circuit without danger. In this case, the load attended by the switching device can be galvanically isolated from the energy supply in the event of a fault (for example, grounding). The switching action can be configured by parameters in the control device, so that not only automatic isolation (when certain conditions exist) but also manual isolation is possible. For this purpose, the conditions for automatic isolation should be transmitted via the data interface during the start-up of the switching device. The manual isolation can be brought about by the superordinate control device via a data interface.

In a further embodiment of the invention, it is recommended that: at least one temperature detection device is provided on a component of the switching device, which can be evaluated by the control device. In this way, automatic switching actions can be carried out when there are inadmissible temperature values and information about these switching actions thus triggered (for example the value of the temperature, the current power at the switching time) can be transmitted to the connected data receiver via the data interface.

The switching device according to the invention can be used with all the usual pole numbers and is used not only for alternating voltage systems but also for direct voltage systems. It is also worth recommending: the switching device is provided with operating elements by means of which switching actions can also be carried out manually directly on the switching device. Also, the switching device itself may be equipped with a display device which displays the status of the switching device (e.g. supply voltage attached/unattached, semiconductor switch closed/open, etc.) directly on the switching device and thus simplifies maintenance or troubleshooting.

Drawings

Wherein:

fig. 1 shows an exemplary switching apparatus, block diagram;

fig. 2 exemplarily shows a control apparatus, a block diagram.

Detailed Description

Fig. 1 shows a block diagram of a switching device, exemplarily and schematically. A block diagram of aswitching device 1 is shown, which is implemented in two poles. This configuration is typical for switching or protection devices in vehicles that switch and protect not only the feeder but also the return, or phase and neutral, lines. For this purpose, asemiconductor switch 2 is provided in thefirst circuit 4 and afurther semiconductor switch 3 is provided in thesecond circuit 5. The current flowing through thefirst circuit 4 is determined by means of a current measuring device 7 and the current flowing through thesecond circuit 5 is determined by means of acurrent measuring device 8. The voltage between thefirst circuit 4 and thesecond circuit 5 is determined by means of avoltage measuring device 9. The outputvoltage measuring device 24 is designed to determine the voltage present at the output of thecircuits 4, 5 and to transmit the value of this voltage to thecontrol device 6. Thetemperature measuring device 25 detects the temperature of theswitching device 1 or of certain components in theswitching device 1 and transmits the value of this temperature to thecontrol device 6. Thecontrol device 6 is designed to receive the measurement signals of themeasuring devices 7, 8, 9, 24, 25 and has a control output for actuating the semiconductor switches 2, 3. Thecontrol device 6 can be embodied, for example, as a memory-programmable controller or as a microcontroller with a program memory and a data memory. The switching device also comprises anenergy supply 12 for the control device and of course a terminal 11 for the electrical connection of thecircuits 4, 5. The data interface 10 is designed for bidirectional data transmission with thecontrol device 6 and can transmit control signals supplied to theswitching device 1 from the outside to the control device and signals generated by thecontrol device 6 to other devices. In thecircuits 4, 5, two-poleelectromechanical disconnectors 13 are arranged, which are actuated by thecontrol device 6 and in this case feed back the switching state of the two-pole electromechanical disconnectors to thecontrol device 6. The switching device shown in fig. 1 by way of example can fulfill several functions because it is possible to determine the currents and voltages in the twocircuits 4, 5, in particular:

on/off without wear

Soft start, e.g. for electric motors or lamps

Switching on a large capacitance

Galvanic isolation of the load

-overcurrent protection

Short-circuit protection

Overvoltage/undervoltage protection

Fault current protection

-arc protection.

In the two-pole embodiment, the function of phase failure protection (motor circuit breaker) is of course not possible, but in the three-pole embodiment it can be implemented very simply. Within the framework of the start-up procedure, specific values, for example trigger characteristics, trigger values and functionalities themselves, can be transmitted to thecontrol device 6 via thedata interface 10, so that one type ofswitching device 1 can perform respectively different tasks.

Fig. 2 shows a block diagram of a control device by way of example and schematically. A block diagram of acontrol device 6 is shown, as it can be used in theswitching device 1 in fig. 1. Thecontrol device 6 includes: adigital computation unit 14, which is set up for executing instruction sequences; and amemory 15 for these instruction sequences and for fixed and variable values. Thecalculation unit 6 also comprises an analog-to-digital converter 16 for the measuredvalues 19 of themeasuring devices 7, 8, 9, 24, 25. The digital values determined by the analog-to-digital converter 16 can be read by thecalculation unit 14. Thedrive circuit 17 can be controlled by thecomputation unit 14 and forwards these signals in a form suitable for the semiconductor switches 2, 3 and the isolatingswitch 13 connected to the drive circuit. Likewise, the feedback of thedisconnector 13 is recognized by thecalculation unit 14 and the signal is suitably prepared for further processing. In addition, a potential separation between the semiconductor switches 2, 3 and thecontrol device 6 can be provided, for example by means of optocouplers or induction transformers between the semiconductor switches 2, 3 and thecontrol device 6. For bidirectional data transmission, thecommunication interface 18 is equipped with thecomputation unit 14 and converts the data characters of thecomputation unit 14 into the data protocol (e.g. TCP/IP) transmitted via thedata interface 10. Within the framework of the start-up procedure, those configuration data which define the respective desired functions of theswitching device 1 are transmitted via the data interface 10 (not shown in fig. 2) to thecomputing unit 14, thecomputing unit 14 storing parameterization data 23 (such as trigger currents, characteristic curves and similar parameterization data) and configuration data which describe the functions of the switching device (protection switches, soft start, etc.) in thememory 15. Furthermore, a switching command is transmitted to theswitching device 1 via thecommunication interface 18, and a value, for example the current electrical power value of the connected electrical consumer, is output to an external monitoring device. Other components, such as a control device for a display device for displaying the state of theswitching device 1 or for detecting a manual input, are not shown in fig. 2.

List of reference numerals

1 electric switching device

2 semiconductor switch of the first circuit

3 semiconductor switch of second circuit

4 first circuit

5 second circuit

6 control device

7 Current measuring device of first circuit

8 Current measuring device of second circuit

9 Voltage measuring device

10 data interface

11 terminal post

12 energy supply device

13 isolating switch

14 calculation unit

15 memory

16A/D converter

17 drive circuit

18 communication interface

19 measured value

20 control signal

21 data

22 switch instruction

23 parameterization data

24 output voltage measuring device

25 temperature measuring means.

Claims (8)

1. An electrical switching apparatus (1) comprising: at least one semiconductor switch (2, 3) arranged in the circuit (4, 5); electrical measuring means (7, 8, 9, 24); a control device (6) which evaluates the measured values determined by the electrical measuring devices (7, 8, 9, 24) and is designed to actuate the semiconductor switches (2, 3), wherein the control device (6) causes an automatically determined actuation of the semiconductor switches (2, 3) when a determined measured value is detected,

characterized in that the conditions for actuating the semiconductor switches (2, 3) can be transmitted to the control device (6) by means of a start-up procedure via a data interface (10), and in that the data interface (10) is set up for receiving switching commands for the semiconductor switches (2, 3).

2. The electrical switching apparatus (1) according to claim 1, characterized in that the control apparatus (6) is set up for transmitting the respective current switching state of the semiconductor switches (2, 3) to the data interface (10).

3. Electrical switching device (1) according to one of claims 1 or 2, characterized in that the control device (6) is set up for transmitting measured values detected by the electrical measuring device (7, 8, 9, 24) to the data interface (10).

4. The electrical switching apparatus (1) according to one of claims 1 to 2, characterized in that the conditions for operating the semiconductor switches (2, 3) are based on a determined course of change of an overcurrent or a short circuit or a phase failure or a fault current or an overvoltage or an undervoltage or a load current.

5. Electrical switching device (1) according to claim 4, characterized in that upon an automatically determined manipulation of the semiconductor switches (2, 3) based on a condition, a signal indicating the condition is attached to the data interface (10).

6. Electrical switching device (1) according to one of claims 1 to 2, characterized in that during a start-up procedure an automatic re-switch-on after an automatically determined switch-off procedure of the semiconductor switches (2, 3) can be predefined via the data interface (10).

7. Electrical switching device (1) according to one of claims 1 to 2, characterized in that the control device (6) transmits the measured values detected by the electrical measuring device (7, 8, 9, 24) to the data interface (10) as soon as they are within a range around that value which causes an automatically determined switching-off process of the semiconductor switch (2, 3).

8. Electrical switching device (1) according to one of claims 1 to 2, characterized in that at least one electromechanically operable switching element (13) is provided in the electrical circuit, which switching element can be actuated by means of the control device (6).

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