A kind of flexible current sensor of for transformer winding deformation monitoringTechnical field
The invention belongs to winding deformation of power transformer monitoring technical field, particularly current signal detection technique field,It is related to a kind of flexible current sensor.
Background technology
At present, the main species of current sensor are rogowski coil formula sensors.When tested current signal comparesWhen faint, usually using the rogowski coil formula current sensor with magnetic core.However, relative permeability is higher at presentSoft magnetic materials, such as ferrite, non-crystaline amorphous metal, ultracrystallite etc. are all solid materials.It is made of this kind of solid permeability magnetic materialSize, the shape of rogowski coil formula current sensor are fixed, and being unsatisfactory for some needs the field of soft, flexible sensorIt closes.
In the detections experiments such as Partial Discharge Detection, the winding deformation detection of power transformer, measuring transformer is often required thatCurrent signal on winding.Previous common current sensor is rogowski coil type current sensor, this sensorIt is not electrically connected directly between tested conducting wire, the current signal in tested conducting wire is detected by electromagnetic induction principle.The application scenarios such as Partial Discharge Detection, the detection of winding deformation swept-frequency signal, Leakage Current detection, tested electric current is very faint, outsidePortion's electromagnetic interference is very strong, it is desirable that this Rogovski type current sensor has outside the magnetic core of high magnetic permeability and forceful electric power magnetic screenShell.Therefore, magnetic core usually selects solid magnetic material.
For the power transformer of on-line operation, best test position is often the root that transformer winding draws thread casingPortion, particularly bushing root.Due to transformer belt electricity operation, site requirement sensor cannot close to strong electric field region, becauseAnd it is more satisfactory sensor placement location outside bushing raising seat.Since transformer high-voltage bushing is thicker, seat is increasedThicker, diameter is up to 700mm.Therefore it is required that the diameter bigger of current sensor, can be sleeved on outside raising seat.
The existing rogowski coil type current sensor based on solid magnetic core, solid barrier shell, if being fabricated toThe annulus of diameter 700mm, machining cost is very high, and carrying, transport, the installation of sensor are also extremely inconvenient, and therefore, it is difficult to winAppoint.
Some existing flexible, flexible sensors, the sensor of some of types is by one section of one section of solidMagnetic core joins end to end, it is common the shortcomings that be the shielding casing that bending can not be synchronized together with magnetic core, it is thus difficultIt is strong to be suitable for weak output signals, the electromagnetic interferences such as the shelf depreciation of power equipment, winding deformation detection signal, Leakage Current signalStrong occasion.
Invention content
The present invention proposes a kind of flexible current sensor, it is characterized in that：
Sensor is by magnetic core（1）, magnetic core sheath（2）, measuring coil（3）, shielding shell（4）, core interface（5）, signalOutput port（6）Composition；Magnetic core（1）By long 300mm, the magnetic band of width 20mm（8）It folds, scope of lamination gross thickness 5mm；MagneticThe magnetic band at core both ends（9）It is fixed together, and the band at middle part is not fixed, magnetic core（1）Both ends can pass throughInterface（5）Dock and keep the spacing of 2mm；Magnetic core sheath（2）It is 240mm for a segment length, section is long 22mm, width 10mm squaresThe plastic flexible pipe of shape, is sleeved on magnetic core（1）On；Measuring coil（3）Magnetic core is wound on by enamel covered wire for one section（1）On, lengthFor 20mm, the number of turn is with measuring the relevant solenoid of frequency band, the diameter of section 0.45mm of used enamel covered wire, coil（3）TwoEnd respectively with signal output port（6）Shell and core wire electrical connection；Shield shell（4）For made of conductive magnetic materialThe rectangular cylinder that section is long 25mm, width 15mm rectangles, wall thickness 2mm, length that is hollow, having 2mm gaps on side wall are 22mm, is sleeved onThe outside of measuring coil 3；Interface（5）By can be formed with the two halves of fastened by screw together, wherein half is fastened on magnetic core（1）One end, the other half is fastened on magnetic core（1）The other end；Work as interface（5）Two halves when being combined, drive magnetic core（1）TwoEnd is in close contact；Signal output port（6）It is BNC type signal cable connectors.
The advantage of the invention is that：
（1）Sensor magnetic core proposed by the present invention is that both ends are fixed, intermediate loose band lamination overlapping forms, becauseAnd can be bent, the occasion of bending sensor can be applicable to.For example, exist very around tested conducting wire or conducting wireDuring thick object, it is desirable that size sensor is very big, and past solid state sensor diameter is big, processing, make, transport, installation it is equalIt is inconvenient；And the flexible sensor of the present invention is easy to process, and it is rollable or transport after stretching, it is very convenient.Therefore, it is thisSensor is highly suitable in deformation of transformer winding monitoring measuring frequency sweep current responsing signal around bushing raising seat.
（2）Sensor proposed by the present invention is one section of lamination, both ends can be docking together by port so that internalMagnetic core formed with 2mm gaps ring.Therefore, in use, without changing testee, only need to be proposed by inventionSensor ring enclosed around testee one, end docking cyclization, installation and its conveniently.
Description of the drawings
Fig. 1 is the magnetic core of sensor of the invention and loop construction schematic diagram；
Fig. 2 is the shielding shell mechanism schematic diagram of the present invention；
Fig. 3 is planing surface schematic diagram when sensor of the invention completes cyclic annular；
Specific embodiment
The utility model is described further with reference to Fig. 1 ~ Fig. 3.
As shown in Figure 1, by the Fe-based amorphous band of multilayer and width for 20mm（8）It stacks, scope of lamination gross thickness reaches5mm, lamination total length 300mm, lamination both ends 30mm range bands（9）It is interior to use poured with epoxy resin, it is not poured into a mould among lamination, shapeInto magnetic core（1）.It since magnetic core is stacked by band, has only done end and has fixed, then magnetic core has certain bending ability.Magnetic core（1）It is placed on magnetic core sheath（2）In,
Measuring coil（3）It is wound on outside magnetic core sheath, away from magnetic core end 10mm.Measuring coil diameter 0.45mmThe 80 circle coils that enamel covered wire turns to.The both ends of enamel covered wire connect BNC ends respectively（6）Core wire and crust；It again will screenCover shell（4）It is sleeved on outside measuring coil.The structure for shielding shell is as shown in Figure 2.
As shown in figure 3, magnetic core（1）Both ends be separately installed with core interface（5）Half.Magnetic core can be bent cyclizationShape；Interface（5）Two halves merge after, magnetic core（1）Both ends pass through interface（5）It is close and keep 2mm gaps, it ensures in measured conductorPower frequency heavy-current caused by magnetic field will not in magnetic core saturation.When in-site installation sensor, interface is first beaten（5）, will passSensor is trapped among outside testee, then by interface（5）It is closed, screws down.
Finally it should be noted that：The above embodiments are merely illustrative of the technical scheme of the present invention and are not intended to be limiting thereof, to the greatest extentPipe is described in detail the present invention with reference to above-described embodiment, those of ordinary skills in the art should understand that：StillThe specific embodiment of the present invention can be modified or replaced equivalently, and without departing from any of spirit and scope of the inventionModification or equivalent replacement, are intended to be within the scope of the claims of the invention.