CN101692102A - Power frequency zero-flux mini-current sensor for capacitive equipment dielectric loss on-line monitoring - Google Patents

Power frequency zero-flux mini-current sensor for capacitive equipment dielectric loss on-line monitoring Download PDF

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Publication number
CN101692102A
CN101692102A CN200910023974A CN200910023974A CN101692102A CN 101692102 A CN101692102 A CN 101692102A CN 200910023974 A CN200910023974 A CN 200910023974A CN 200910023974 A CN200910023974 A CN 200910023974A CN 101692102 A CN101692102 A CN 101692102A
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resistance
magnetic core
current sensor
circuit module
opa
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CN200910023974A
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CN101692102B (en
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韩元斌
梁红军
王长安
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Xi'an Boyuan Electric Co Ltd
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Xi'an Boyuan Electric Co Ltd
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Abstract

A power frequency zero-flux mini-current sensor for capacitive equipment dielectric loss on-line monitoring comprises a working magnetic core 1, wherein a test coil 3 is winded round the working magnetic core 1, a secondary side coil 2 is winded round the test coil 3 in the inverse direction, shielding layers 4 are arranged between the secondary side coil 2 and the test coil 3, and the test coil 3 and the working magnetic core 1, the test coil 3 is connected with a compensation circuit module 5, the output end of the compensation circuit module 5 is connected with one end of the secondary side coil 2, the other end of the secondary side coil 2 is connected with an output circuit module 6, the two ends of the test coil 3 generate induced potential, the induced current is added to the output end of the compensation circuit module 5 to generate secondary current for the secondary side coil 2, the compensation circuit module 5 is used to test the potential difference of the test coil 3, the magnetic flux in the working magnetic core is almost equal to zero; and if the test value deviates the permissible value, the working magnetic core can be adjusted automatically to keep in almost zero-flux state, and the mini-current sensor has high reliability and is characterized by simple structure, little production difficulty and low cost.

Description

Capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor
Technical field
The present invention relates to electrotechnical measurement and use the current sensor field, particularly a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor.
Background technology
The safe operation of high-tension power transmission and transformation equipment is the key factor that influences power system security, stable and economical operation, and high-tension apparatus generation insulation fault not only can cause equipment damage itself, but also can cause many-sided loss.Converting equipments such as coupling condenser, condenser-type terminal, current transformer and capacitance type potential transformer all can be regarded the capacitance type equipment that is connected in series by a plurality of capacitors as.Their quantity of adding up accounts for power transmission and transformation and becomes about half of equipment.
Along with the development of intelligent grid, electric system is to the insulation parameter of capacitive apparatus, and especially Leakage Current, dielectric loss etc. are carried out on-line monitoring and just become extremely urgent problem.The technology majority that insulated on-line monitoring system adopted that uses at present both at home and abroad is a capacitive apparatus end screen Leakage Current monitoring method, by to the mensuration of Leakage Current amplitude and phase angle, analyze and compare, thereby judge the insulation status of high-tension apparatus.Leakage Current was less when capacitive apparatus was worked in normal condition, and generally in tens milliamperes, the dielectric loss value is many about 3/1000ths, thereby higher to performance requirements such as the degree of accuracy of monitoring sensor, angle error, stability, signal to noise ratio (S/N ratio)s.Its gordian technique is the collection of Leakage Current, and main method is to adopt the current sensor of high precision, high stability.
Above-mentioned requirements seems particularly important to high precision, high stable type electric current.Because the Leakage Current of insulation is in tens milliamperes, so sensor could obtain than higher output signal selecting high permeability material for use.
Current sensor is realized NE BY ENERGY TRANSFER by first siding ring and second siding ring by electromagnetic coupled, the schematic circuit of small electric current sensor, I 1Be small electric current sensor primary side current, I 2Be secondary side current, I 0Be exciting curent.N 1, N 2Be respectively first and second coil turn.Therefore, the magnetic potential balance equation of this small electric current sensor is:
I 1N 1+I 2N 2=-I 0N 1
As excitatory ampere-turn I 0N 1When being zero, I 1N 1=-I 2N 2, i.e. secondary ampere-turn variation can reflect fully that former limit ampere-turn changes, error is zero.The general I that claims 0N 1Be absolute error, I 0N 1/ I 1N 1Be relative error.The error of current sensor is plural error, and available ratio difference f and angular difference δ represent.
ε=-I 0N 1/I 1N 1=f+jδ
F=(I in the formula 2N 2/ I 1N 1)/I 1* 100%, δ is I 2After counterclockwise 180 ° with I 1Angle.
This shows, because I 0N 1Existence, make I 2N 2With I 1N 1There are angular difference δ and ratio difference f.If I 0=0, then excitatory magnetic potential is 0, and error is zero.The iron core of this moment is in " zero magnetic flux " state, and the The initial segment that it works in magnetization curve is a linearity range.At this moment, the current sensor output waveform just can not distort, and keeps good linearty.This is " zero magnetic flux principle ".In fact, no exciting curent does not just have magnetic flux in the iron core, and once the NE BY ENERGY TRANSFER relation with secondary has not just existed, and current sensor can not be worked under this state.Therefore, if can make the sensor iron core be in zero magnetic flux state all the time, just can fundamentally eliminate the error of current sensor.But, by the principle of work of sensor as can be known, be impossible realize zero magnetic flux by sensor self, compensation or adjustment that must outer boundary condition.For this reason, adopt the correct compensation method-dynamic compensation electronic circuit of selecting that it is dynamically adjusted, make iron core be in dynamically zero magnetic flux state all the time, at this moment current sensor will have high precision.
At present, the patent No. discloses a kind of zero flux current sensor dynamic compensation technology for the Chinese patent of [02148574.7]: its structure is a main magnetic core stack auxiliary magnetic core, coiling primary winding, second siding ring on the stack magnetic core, coiling magnetic test coil on main magnetic core, coiling compensating coil on auxiliary magnetic core.Magnetic test coil detects that the magnetic of main magnetic core is close to feed back to compensating coil by electronic circuit, for the auxiliary magnetic core electric current that affords redress is offset exciting curent.Though also realized the dynamically zero magnetic flux state of sensor, the complex structure of its sensor, and main magnetic core must have identical magnetization characteristic and size with auxiliary magnetic core, and manufacture difficulty and cost are all bigger.
Summary of the invention
In order to overcome above-mentioned the deficiencies in the prior art, the object of the present invention is to provide a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor, only need a work magnetic core, coiling second siding ring and magnetic test coil can be provided with the zero magnetic flux duty that magnetic flux mobile equilibrium reaches current sensor accurately by electronic circuit in the above, its physical arrangement is a punching, with the complete electric insulation of tested high voltage electric power equip ment, the reliability height, and have characteristics simple in structure, that manufacture difficulty is little and cost is low.
To achieve these goals, the technical solution used in the present invention is: a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor, comprise a work magnetic core 1, coiling magnetic test coil 3 on work magnetic core 1, coiling second siding ring 2 in the other direction on magnetic test coil 3 again, between second siding ring 2 and the magnetic test coil 3, magnetic test coil 3 and work is equipped with screen layer 4 between the magnetic core 1, magnetic test coil 3 connects compensating circuit module 5, the output terminal of compensating circuit module 5 is connected with an end of secondary coil 2, another termination output circuit module 6 of secondary coil 2.
Described work magnetic core 1 material selection permalloy material.
The physical arrangement of described work magnetic core 1 is the punching non-cpntact measurement.
Screen layer 4 adopts aluminium foil to make.
Advantage of the present invention and effect:
(1) sensor is made up of a work magnetic core and electronic circuit board two parts, and inner structure is simple, is easy to make;
(2) sensor is the punching structure, only needs when measuring capacitive apparatus end screen Leakage Current it is enclosed within on the screen ground wire of end get final product, with the electric insulation completely of measurement equipment fully, reliability height;
(3) the multilayer screen structure is adopted in high precision conversion, Low ESR output, has good on-the-spot antijamming capability.
Description of drawings
Fig. 1 is a sensor internal physical arrangement synoptic diagram of the present invention.
Fig. 2 is a sensor construction schematic diagram of the present invention.
Fig. 3 is the circuit diagram of compensating circuit module 5 of the present invention.
Fig. 4 is the circuit diagram of output circuit module 6 of the present invention.
Embodiment
Below in conjunction with accompanying drawing structural principle of the present invention and principle of work are described in further detail.
With reference to Fig. 1, a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor internal physical structure comprises a work magnetic core 1, coiling second siding ring 2 and magnetic test coil 3 on work magnetic core 1.Concrete winding structure is to adopt enameled wire coiling magnetic test coil 3 on work magnetic core 1, on magnetic test coil 3, adopt enameled wire coiling in the other direction second siding ring 2 again, between second siding ring 2 and the magnetic test coil 3, magnetic test coil 3 is equipped with screen layer 4 between the magnetic core 1 with working.
With reference to Fig. 2, be Fundamentals of Sensors synoptic diagram of the present invention, wherein magnetic test coil 3 connects compensating circuit module 5, and the output terminal of compensating circuit module 5 is connected with an end of secondary coil 2, another termination output circuit module 6 of secondary coil 2.Work magnetic core 1 material selection permalloy material.Screen layer 4 all adopts the high aluminium foil of magnetoconductivity to make.
The magnetic test coil 3 magnetic flux state in the Real-time and Dynamic Detection work magnetic core 1 that is connected with compensating circuit 5, compensating circuit 5 has very high input impedance, magnetic test coil 3 is equivalent to open circuit, its induced potential is the excitatory magnetic potential of work magnetic core 1, produce a demagnetizing current after these electromotive force process compensating circuit 5 amplification filtering, and it is fed back to secondary coil 2, output circuit module 6 is to export to back level load circuit behind the voltage with the current transformation in the secondary coil 2.
With reference to Fig. 3, compensating circuit module 5 of the present invention comprises resistance R 1, resistance R 1One end ground connection, the other end and amplifier OPA 1In-phase end join; Resistance R 2One end is a signal input part, just connects an end of the magnetic test coil 3 among the present invention, another termination amplifier OPA 1Backward end; Resistance R 3Be feedback resistance, a termination amplifier OPA 1Output terminal, the other end and amplifier OPA 1In-phase end join; Capacitor C 1Be attempted by resistance R 3Two ends; Capacitor C 2One termination amplifier OPA 1Output terminal, an end is the signal output part of this circuit, just connects an end of the second siding ring 2 among the present invention; Resistance R 4One end ground connection, the output terminal of another this circuit of termination.
The principle of work of compensating circuit module 5 is the magnetic flux states in the Real-time and Dynamic Detection work magnetic core 1, to the induced potential signal in the magnetic test coil 3 carry out that homophase amplifies and filtering after, for secondary coil 2 provides demagnetizing current.
With reference to Fig. 4, output circuit module 6 of the present invention comprises resistance R 6, resistance R 6One end ground connection, the other end and amplifier OPA 2In-phase end join; Resistance R 5One end is this circuit signal input end, just connects an end of the second siding ring 2 among the present invention, another termination amplifier OPA 2Backward end; Resistance R 7One termination amplifier OPA 2Output terminal, the other end and this circuit signal input end join; Capacitor C 3Be attempted by resistance R 7Two ends; Amplifier OPA 2Output terminal be the signal output part of this circuit.
The principle of work of output circuit module 6 is to export to back level load circuit after the sensor current signal in the secondary coil 2 is converted into voltage signal, and this circuit has very low output impedance, and on-the-spot antijamming capability is strong, can long cable transmission.
Principle of work of the present invention is:
With reference to Fig. 2, magnetic test coil 3 two ends produce the input end that the induced potential induction current is added to compensating circuit 5, produce secondary current again and offer secondary coil 2, the secondary coil electric current is all supplied with by compensating circuit 5, the electric potential difference at compensating circuit module 5 high speed detection of dynamic magnetic test coils 3 two ends, when electric potential difference enough little (be approximately zero permissible value), magnetic flux in the work magnetic core promptly is approximately zero magnetic flux, if detected value departs from permissible value, then automatic high speed adjustment, the work magnetic core of making can remain at and approach zero magnetic flux state, and sensor reaches higher precision.

Claims (6)

1. capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor, comprise a work magnetic core (1), it is characterized in that, go up coiling magnetic test coil (3) at work magnetic core (1), go up coiling second siding ring (2) in the other direction at magnetic test coil (3) again, between second siding ring (2) and the magnetic test coil (3), be equipped with screen layer (4) between magnetic test coil (3) and the work magnetic core (1), magnetic test coil (3) connects compensating circuit module (5), the output terminal of compensating circuit module (5) is connected with an end of secondary coil (2), another termination output circuit module (6) of secondary coil (2).
2. a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor according to claim 1 is characterized in that, described work magnetic core (1) material selection permalloy material.
3. a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor according to claim 1 is characterized in that the physical arrangement of described work magnetic core (1) is the punching non-cpntact measurement.
4. a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor according to claim 1 is characterized in that, screen layer (4) adopts aluminium foil to make.
5. a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor according to claim 1 is characterized in that described compensating circuit module (5) comprises resistance (R 1), resistance (R 1) an end ground connection, the other end and amplifier (OPA 1) in-phase end join; Resistance (R 2) end is signal input part, another termination amplifier (OPA 1) backward end; Resistance (R 3) be feedback resistance, a termination amplifier (OPA 1) output terminal, the other end and amplifier (OPA 1) in-phase end join; Electric capacity (C 1) be attempted by resistance (R 3) two ends; Electric capacity (C 2) a termination amplifier (OPA 1) output terminal, an end is the signal output part of this circuit, resistance (R 4) an end ground connection, the output terminal of another this circuit of termination.
6. a kind of capacitive equipment dielectric loss on-line monitoring recruitment power frequency zero-flux small electric current sensor according to claim 1 is characterized in that described output circuit module (6) comprises resistance (R 6), resistance (R 6) an end ground connection, the other end and amplifier (OPA 2) in-phase end join; Resistance (R 5) end is this circuit signal input end, another termination amplifier (OPA 2) backward end; Resistance (R 7) a termination amplifier (OPA 2) output terminal, the other end and this circuit signal input end join; Electric capacity (C 3) be attempted by resistance (R 7) two ends; Amplifier (OPA 2) output terminal be the signal output part of this circuit.
CN2009100239740A 2009-09-18 2009-09-18 Power frequency zero-flux mini-current sensor for capacitive equipment dielectric loss on-line monitoring Expired - Fee Related CN101692102B (en)

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102129018A (en) * 2011-01-13 2011-07-20 华北电力大学 Insulation online monitoring method for high-voltage capacitive equipment
CN102128971A (en) * 2011-01-13 2011-07-20 华北电力大学 Insulated and charged testing device for capacitive equipment and method thereof
CN102346213A (en) * 2011-08-09 2012-02-08 刘睿刚 Weak current detection sensor
CN102944739A (en) * 2012-11-14 2013-02-27 广东电网公司中山供电局 Large-aperture forcipate micro-current sensor device
CN103091532A (en) * 2011-10-28 2013-05-08 上海汽车集团股份有限公司 Electric current transducer used for automobile and based on zero magnetic flux compensation
CN103399192A (en) * 2013-08-02 2013-11-20 广西电网公司电力科学研究院 Split type zero flux small electric current sensor for on-line monitoring and charged test of capacitive equipment
CN103592490A (en) * 2013-10-21 2014-02-19 中国电力科学研究院 High-accuracy electronic compensated current transformer
CN105575639A (en) * 2014-10-17 2016-05-11 国家电网公司 Broadband current transformer
CN108226603A (en) * 2016-12-13 2018-06-29 保时捷股份公司 For measuring the device and method of the electric current in electric conductor
CN109188048A (en) * 2018-07-31 2019-01-11 中国地质大学(武汉) A kind of contactless weak current sensor based on passive zero flux
CN111157776A (en) * 2020-01-14 2020-05-15 清华大学 Double-magnetic-core sensor for insulation leakage current of power equipment
CN111880123A (en) * 2020-07-21 2020-11-03 华北电力大学 Method for detecting frequency response signal of transformer winding resisting power frequency magnetic saturation
CN112415249A (en) * 2020-11-09 2021-02-26 武汉大学 Zero-flux current transformer and error modulation method

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102128971B (en) * 2011-01-13 2014-12-03 华北电力大学 Insulated and charged testing device for capacitive equipment and method thereof
CN102128971A (en) * 2011-01-13 2011-07-20 华北电力大学 Insulated and charged testing device for capacitive equipment and method thereof
CN102129018A (en) * 2011-01-13 2011-07-20 华北电力大学 Insulation online monitoring method for high-voltage capacitive equipment
CN102346213A (en) * 2011-08-09 2012-02-08 刘睿刚 Weak current detection sensor
CN103091532A (en) * 2011-10-28 2013-05-08 上海汽车集团股份有限公司 Electric current transducer used for automobile and based on zero magnetic flux compensation
CN102944739B (en) * 2012-11-14 2015-08-19 广东电网公司中山供电局 Large-aperture forcipate micro-current sensor device
CN102944739A (en) * 2012-11-14 2013-02-27 广东电网公司中山供电局 Large-aperture forcipate micro-current sensor device
CN103399192A (en) * 2013-08-02 2013-11-20 广西电网公司电力科学研究院 Split type zero flux small electric current sensor for on-line monitoring and charged test of capacitive equipment
CN103592490A (en) * 2013-10-21 2014-02-19 中国电力科学研究院 High-accuracy electronic compensated current transformer
CN103592490B (en) * 2013-10-21 2017-06-16 国家电网公司 A kind of high accuracy electronic compensation type current transformer
CN105575639A (en) * 2014-10-17 2016-05-11 国家电网公司 Broadband current transformer
CN105575639B (en) * 2014-10-17 2018-06-01 国家电网公司 A kind of wideband current transformer
CN108226603A (en) * 2016-12-13 2018-06-29 保时捷股份公司 For measuring the device and method of the electric current in electric conductor
CN108226603B (en) * 2016-12-13 2020-07-28 保时捷股份公司 Device and method for measuring current in electrical conductor
CN109188048A (en) * 2018-07-31 2019-01-11 中国地质大学(武汉) A kind of contactless weak current sensor based on passive zero flux
CN111157776A (en) * 2020-01-14 2020-05-15 清华大学 Double-magnetic-core sensor for insulation leakage current of power equipment
CN111880123A (en) * 2020-07-21 2020-11-03 华北电力大学 Method for detecting frequency response signal of transformer winding resisting power frequency magnetic saturation
CN111880123B (en) * 2020-07-21 2022-10-25 华北电力大学 Method for detecting frequency response signal of transformer winding resisting power frequency magnetic saturation
CN112415249A (en) * 2020-11-09 2021-02-26 武汉大学 Zero-flux current transformer and error modulation method

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