CN205374572U - Capacitive equipment earth current sampling device - Google Patents
Capacitive equipment earth current sampling device Download PDFInfo
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- CN205374572U CN205374572U CN201521124508.9U CN201521124508U CN205374572U CN 205374572 U CN205374572 U CN 205374572U CN 201521124508 U CN201521124508 U CN 201521124508U CN 205374572 U CN205374572 U CN 205374572U
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Abstract
The utility model provides a capacitive equipment earth current sampling device, produces module and IU conversion and signal amplification module including setting up in the intraformational punching current transformer of a plurality of shieldings, dynamic verification and balancing control electric current, current transformer installs on the earth connection of capacitive equipment, and it has detecting coil and vice limit winding to wind on its iron core, dynamic verification and balancing control electric current produce the output of the input termination detecting coil of module, and the output connects the input of IU conversion and signal amplification module through vice limit winding, the input of the electrified detector of output termination capacitive insulation of equipment of IU conversion and signal amplification module. The utility model discloses a weak current sensor, the work of messenger's iron core utilizes the multilayer shield to prevent external electromagnetic interference at magnetization curve's linearity range simultaneously, makes the output waveform of current sampling device not take place the distortion to reduce the sampling error of electric current, improved the detection precision of capacitive character insulation of equipment situation.
Description
Technical field
This utility model relates to a kind of interface arrangement for the earth current of capacitive equipment and detecting instrument being connected, and belongs to field of measuring technique.
Background technology
The current sampling device of existing capacitive equipment insulating tape electro-detection instrument is broadly divided into two kinds, i.e. wiring cell type and sensor type.The major function of wiring cell type sampler is to provide the leading-out terminal of a current test signal and prevents end shield from opening a way, there is no signal measurement function, during test, by test cable, electric current need to be introduced the high accuracy punching current sensor measurement within testing instrument for electrified.Sensor type sampler is to utilize current sensor that capacitive apparatus end shield (or low-pressure end) is carried out current sampling, mostly the current sensor being applied to power system at present is electromagnetic coupled formula sensor (being divided into punching, caliper brake etc.), owing to capacitive equipment insulating tape electro-detection instrument is operated in strong-electromagnetic field environment, and sampled signal is little, therefore its certainty of measurement is very easily by the impact of peripheral electromagnetic field.Additionally, the magnetic potential balance relation based on the sensor type current sampling device of electromagnetic coupled principle is: N1I1+N2I2=N1I0(wherein N1And N2The respectively number of turn of primary side winding and vice-side winding, I0、I1And I2Respectively exciting curent, primary side winding electric current and secondary winding current), i.e. primary magnetomotive force+secondary magnetic potential=excitatory magnetic potential in former limit, due to the excitatory ampere-turn N in former limit1I0It is not zero, secondary ampere-turn N2I2Change can not reflect former limit ampere-turn N completely1I1Change, N1I0More big, the linearity of iron core magnetization curve is more poor, and the distortion of output waveform is more serious, and the error of sampling of current signal is also more big.
Utility model content
The purpose of this utility model is in that the drawback for prior art, it is provided that a kind of high-precision capacitive apparatus earth current sampler, to reduce the detection error of capacitive equipment insulation status.
Problem described in the utility model solves with following technical proposals:
A kind of capacitive apparatus earth current sampler, including the straight-through current transformer being arranged in multiple screen layer, dynamically detection and balanced adjustment current generating module and I/U are changed and signal amplification module, described current transformer is arranged on the earth lead of capacitive apparatus, its iron core is wound with detection coil and vice-side winding, the outfan of the input termination detection coil of described dynamic detection and balanced adjustment current generating module, outfan connects the input of I/U conversion and signal amplification module through vice-side winding, the output of described I/U conversion and signal amplification module terminates the input of capacitive apparatus insulated live detection instrument.
Above-mentioned capacitive apparatus earth current sampler, described dynamic detection and balanced adjustment current generating module include the first operational amplifier, four resistance, four electric capacity and two diodes, the in-phase input end of the first operational amplifier connects the signal output part of the detection coil of current transformer through the first resistance, inverting input connects the earth terminal of detection coil through the second resistance, 3rd resistance and the first electric capacity are all attempted by between inverting input and the outfan of the first operational amplifier, the first diode and the second diode that second electric capacity is connected with inverse parallel are all attempted by the two ends detecting coil, 3rd electric capacity and the 4th electric capacity reversely concatenate after one termination the first operational amplifier outfan, the other end is through the 4th resistance eutral grounding the input connecing I/U conversion and signal amplification module through the vice-side winding of current transformer.
Above-mentioned capacitive apparatus earth current sampler, described I/U conversion and signal amplification module include the second operational amplifier, the 5th electric capacity, four resistance and seven diodes, the in-phase input end ground connection of the second operational amplifier, inverting input connects the vice-side winding of current transformer through the 5th resistance, and output terminates the input of capacitive apparatus insulated live detection instrument；The outfan of one termination the second operational amplifier of the 5th electric capacity and the 6th resistance, the vice-side winding of another termination current transformer；The anode of the 3rd diode, the 4th diode and the 5th diode meets the power input VCC-of this device through the 7th resistance after linking together, the negative electrode of the 5th diode, the 6th diode and the 7th diode meets the power input VCC+ of this device through the 8th resistance after linking together, the negative electrode of the 3rd diode and the anode of the 6th diode connect the vice-side winding of current transformer, the negative electrode of the 4th diode and the anode of the 7th diode and connect the outfan of the second operational amplifier；One end ground connection after 8th diode and the 9th diode inverse parallel connection, the inverting input of termination second operational amplifier.
Above-mentioned capacitive apparatus earth current sampler, described screen layer includes magnetic masking layer and shield layer, and described magnetic masking layer arranges two-layer, and described shield layer is positioned at the outside of magnetic masking layer.
Above-mentioned capacitive apparatus earth current sampler; composition also includes power source protective module; described power source protective module includes two resistance, two diodes and four electric capacity; 9th resistance is connected between power input VCC-and the VCCIN-of external power source of this device; one end ground connection of the tenth diode, the 6th electric capacity and the 7th electric capacity, the VCCIN-end of a termination external power source；Tenth resistance is connected between power input VCC+ and the VCCIN+ of external power source of this device, one end ground connection of the 11st diode, the 8th electric capacity and the 9th electric capacity, the VCCIN+ end of a termination external power source.
This utility model adopts the weak current sensor based on Zero flux principle, makes iron core be operated in the linearity range of magnetization curve；Utilizing multilayer screen to prevent outside electromagnetic interference simultaneously, make the output waveform of current sampling device not be distorted, thus reducing the error of sampling of electric current, improve the accuracy of detection of capacitive equipment insulation status.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the utility model is described in further detail.
Fig. 1 is electricity theory diagram of the present utility model；
Fig. 2 is electrical schematic diagram.
In figure, each label is expressed as: CT, current transformer, F1, the first operational amplifier, F2, the second operational amplifier, L1, primary side winding, LD, detection coil, L2, vice-side winding, R1～R10, the first resistance～the tenth resistance, C1～C9, the first electric capacity～the 9th electric capacity, D1～D11, the first diode～the 11st diode.
Detailed description of the invention
Referring to Fig. 1, this utility model includes being wound with detection coil L on iron coreDWith vice-side winding L2Straight-through current transformer CT, dynamically detection and balanced adjustment current generating module, I/U conversion and signal amplification module and power source protective module.Power source protective module is introduced positive and negative 12V power supply by test cable by capacitive apparatus insulated live detection instrument, provides power supply for the electronic device on whole circuit board.
This device have employed multilayer screen structure, and wherein outermost layer is shield layer, adopts the aluminum alloy materials of high conductivity thick for 2mm；And magnetic shield is divided into inside and outside two-layer, it is respectively adopted 1mm thickness high permeability permalloy material and the iron sheet of 1mm thickness high-saturation magnetic induction density.Avoid outside electromagnetic interference well, improve the certainty of measurement of sensor.
Dynamically detection and balanced adjustment current generating module and detection coil LDIt is connected, dynamically detects L at a high speedDThe electric potential difference at two ends, when electric potential difference sufficiently small (being approximately the permissible value of 0), namely the magnetic flux in iron core is approximately zero, if detected value deviation permissible value, then it adjusts automatically, produces self-balancing and adjusts electric current I2It is supplied to vice-side winding L2, I2The magnetic flux produced, to iron core degaussing, makes iron core reach approximate zero magnetic flux.
I/U conversion and signal amplification module are by the current signal I of vice-side winding2Become voltage signal and amplify, then passing through test lead and introduce capacitive apparatus insulated live detection instrument.
Referring to Fig. 2, it is wound on the detection coil L on iron coreDOne end ground connection, the other end draws detection electric current.Between its two ends and connect two reverse diodes, i.e. the first diode D1 and the second diode D2, dynamically detects back and self-balancing adjusts circuit realiration voltage protection.Second electric capacity C2 is connected in parallel on D1, D2 two ends, and the first resistance R1 is connected to detection coil LDSignal output part and the in-phase input end of the first operational amplifier F1, one end ground connection of the second resistance R2, the other end and the 3rd resistance R3, the first electric capacity C1 are connected to the inverting input of the first operational amplifier F1 together, and the other end of the 3rd resistance R3 and the first electric capacity C1 is connected to the outfan of the first operational amplifier F1.3rd two electrochemical capacitors of electric capacity C3 and the four electric capacity C4() reversal connection of connecting, the other end of the 3rd electric capacity C3 and the outfan of the first operational amplifier F1 are connected, the other end of the 4th electric capacity C4 is through the 4th resistance R4 ground connection, and draws the current signal after adjustment to vice-side winding L2。
In Fig. 2; 3rd diode D3 of I/U conversion and signal amplification module～the 7th diode D7 realizes the input of this module is protected; the output signal SOUT of the second operational amplifier F2 is protected, it is prevented that the signal entering capacitive apparatus insulated live detection instrument exceedes its measurement scope simultaneously.Vice-side winding L2With the negative electrode of the 3rd diode D3, the anode of the 6th diode D6 and the 5th resistance R5, the 6th resistance R6, the 5th electric capacity C5 one end be connected, the other end of the 5th resistance R5 and the inverting input of the second operational amplifier F2 connect, the other end of the 6th resistance R6 and the five electric capacity C5 is connected to the outfan of the second operational amplifier F2, and output voltage signal SOUT extremely capacitive apparatus insulated live detection instrument, one end ground connection after 8th diode D8, the 9th diode D9 reversal connection parallel connection, the inverting input of a termination second operational amplifier F2.
In Fig. 2, VCCIN+ and VCCIN-originates from the positive 12V of capacitive apparatus insulated live detection instrument and negative 12V power supply terminal, and they provide power supply for power source protective module.
In the power source protective module of Fig. 2, each power supply lead wire place electrochemical capacitor in parallel respectively (VCCIN-connects the 6th electric capacity C6, VCCIN+ and meets the 8th electric capacity C8) and conventional capacitive (VCCIN-connects the 7th electric capacity C7, VCCIN+ and meets the 9th electric capacity C9) realize filtering.The tenth resistance R10 that connects on VCCIN+ lead-in wire exports VCC+, prevent instantaneous overcurrent from back electronic devices and components being caused damage, the high potential end of R10 is connected with the negative electrode of the 11st diode D11, the plus earth of D11, realize the clamper to output voltage VCC+, it is prevented that back electronic devices and components are caused damage by overvoltage；In like manner, the 9th resistance R9 that VCCIN-lead-in wire is connected exports the anode of low potential termination the tenth diode D10 of VCC-, R9, the minus earth of D10, it is achieved the clamper to output voltage VCC-.
Vice-side winding L in Fig. 22On current signal be converted to voltage signal by the second operational amplifier F2 and peripheral circuit thereof and amplify output, final sampled signal SOUT delivers to capacitive apparatus insulated live detection instrument.
This device is characterised by the detection coil L in Fig. 2DBeing wrapped on iron core, the little electromotive force at its two ends comes from exciting curent I in iron core0The change of the residual magnetic flux amount brought, after this induction electromotive force is amplified by the first operational amplifier F1, exports a current signal through two reversal connection electrochemical capacitors of C3, C4 after straight, if detection winding LDTwo ends electromotive force becomes big (illustrating that in iron core, magnetizing flux quantitative change is big), then the current signal of this module output becomes big, i.e. vice-side winding LDOn I2Become big, due to I2The magnetic flux produced and primary side winding L1In electric current I1The flow direction produced is contrary, and size is similar to, and therefore can play the effect to iron core degaussing, and then make detection winding LDOn electromotive force diminish, under dynamically detection at a high speed and adjusting, the magnetic flux in iron core approaches Zero flux state always, ideally, I2All by dynamically detecting and the offer of balanced adjustment current generating module, and not from induction electromotive force obtaining current.Iron core, when " Zero flux " state, works in the initial period (linearity range) of magnetization curve, and current sensor output waveform would not distort, thus reaching higher certainty of measurement.
Claims (5)
1. a capacitive apparatus earth current sampler, it is characterized in that, change and signal amplification module including the straight-through current transformer (CT) being arranged in multiple screen layer, dynamic detection and balanced adjustment current generating module and I/U, described current transformer (CT) is arranged on the earth lead of capacitive apparatus, and its iron core is wound with detection coil (LD) and vice-side winding (L2), the input termination detection coil (L of described dynamic detection and balanced adjustment current generating moduleD) outfan, outfan is through vice-side winding (L2) connecing I/U conversion and the input of signal amplification module, the output of described I/U conversion and signal amplification module terminates the input of capacitive apparatus insulated live detection instrument.
2. a kind of capacitive apparatus earth current sampler according to claim 1, it is characterized in that, described dynamic detection and balanced adjustment current generating module include the first operational amplifier (F1), four resistance, four electric capacity and two diodes, and the in-phase input end of the first operational amplifier (F1) meets the detection coil (L of current transformer (CT) through the first resistance (R1)D) signal output part, inverting input through the second resistance (R2) connect detection coil (LD) earth terminal, 3rd resistance (R3) and the first electric capacity (C1) are all attempted by between inverting input and the outfan of the first operational amplifier (F1), and the first diode (D1) and the second diode (D2) that the second electric capacity (C2) is connected with inverse parallel are all attempted by detection coil (LD) two ends, the outfan of a termination the first operational amplifier (F1) after 3rd electric capacity (C3) and the 4th electric capacity (C4) reversely concatenation, the other end is through the 4th resistance (R4) ground connection and through the vice-side winding (L of current transformer (CT)2) connect I/U conversion and the input of signal amplification module.
3. a kind of capacitive apparatus earth current sampler according to claim 1 and 2, it is characterized in that, described I/U conversion and signal amplification module include the second operational amplifier (F2), the 5th electric capacity (C5), four resistance and seven diodes, the in-phase input end ground connection of the second operational amplifier (F2), inverting input meets the vice-side winding (L of current transformer (CT) through the 5th resistance (R5)2), output terminates the input of capacitive apparatus insulated live detection instrument；The outfan of one termination the second operational amplifier (F2) of the 5th electric capacity (C5) and the 6th resistance (R6), the vice-side winding (L of another termination current transformer (CT)2)；The anode of the 3rd diode (D3), the 4th diode (D4) and the 5th diode (D5) meets the power input VCC-of this device through the 7th resistance (R7) after linking together, the negative electrode of the 5th diode (D5), the 6th diode (D6) and the 7th diode (D7) meets the power input VCC+ of this device through the 8th resistance (R8) after linking together, the negative electrode of the 3rd diode (D3) and the anode of the 6th diode (D6) meet the vice-side winding (L of current transformer (CT)2), the negative electrode of the 4th diode (D4) and the anode of the 7th diode (D7) connect the outfan of the second operational amplifier (F2)；One end ground connection after 8th diode (D8) and the 9th diode (D9) inverse parallel connection, the inverting input of a termination the second operational amplifier (F2).
4. a kind of capacitive apparatus earth current sampler according to claim 3, is characterized in that, described screen layer includes magnetic masking layer and shield layer, and described magnetic masking layer arranges two-layer, and described shield layer is positioned at the outside of magnetic masking layer.
5. a kind of capacitive apparatus earth current sampler according to claim 4; it is characterized in that; composition also includes power source protective module; described power source protective module includes two resistance, two diodes and four electric capacity; 9th resistance (R9) is connected between power input VCC-and the VCCIN-of external power source; one end ground connection of the tenth diode (D10), the 6th electric capacity (C6) and the 7th electric capacity (C7), the VCCIN-end of a termination external power source；Tenth resistance (R10) is connected between power input VCC+ and the VCCIN+ of external power source of this device, one end ground connection of the 11st diode (D11), the 8th electric capacity (C8) and the 9th electric capacity (C9), the VCCIN+ end of a termination external power source.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521124508.9U CN205374572U (en) | 2015-12-31 | 2015-12-31 | Capacitive equipment earth current sampling device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201521124508.9U CN205374572U (en) | 2015-12-31 | 2015-12-31 | Capacitive equipment earth current sampling device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107797007A (en) * | 2017-11-16 | 2018-03-13 | 国家电网公司 | A kind of check system and the method for inspection of live capacitive apparatus on-Line Monitor Device |
| CN108120859A (en) * | 2017-12-29 | 2018-06-05 | 国网江苏省电力有限公司检修分公司 | A kind of active electric magnetic screen generating means |
| CN110988442A (en) * | 2019-12-23 | 2020-04-10 | 乐清市西崎电气科技有限公司 | Multi-coaxial pulse shunt |
| CN113419099A (en) * | 2021-06-18 | 2021-09-21 | 清华大学深圳国际研究生院 | Current measuring device |
-
2015
- 2015-12-31 CN CN201521124508.9U patent/CN205374572U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107797007A (en) * | 2017-11-16 | 2018-03-13 | 国家电网公司 | A kind of check system and the method for inspection of live capacitive apparatus on-Line Monitor Device |
| CN107797007B (en) * | 2017-11-16 | 2023-12-15 | 国家电网公司 | Verification system and verification method for on-site capacitive equipment on-line monitoring device |
| CN108120859A (en) * | 2017-12-29 | 2018-06-05 | 国网江苏省电力有限公司检修分公司 | A kind of active electric magnetic screen generating means |
| CN108120859B (en) * | 2017-12-29 | 2024-04-12 | 国网江苏省电力有限公司检修分公司 | Active electromagnetic shielding generating device |
| CN110988442A (en) * | 2019-12-23 | 2020-04-10 | 乐清市西崎电气科技有限公司 | Multi-coaxial pulse shunt |
| CN113419099A (en) * | 2021-06-18 | 2021-09-21 | 清华大学深圳国际研究生院 | Current measuring device |
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