CN101769947B - Detection impedance - Google Patents
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- CN101769947B CN101769947B CN2009100760969A CN200910076096A CN101769947B CN 101769947 B CN101769947 B CN 101769947B CN 2009100760969 A CN2009100760969 A CN 2009100760969A CN 200910076096 A CN200910076096 A CN 200910076096A CN 101769947 B CN101769947 B CN 101769947B
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- 238000001514 detection method Methods 0.000 title claims abstract description 61
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Abstract
The invention provides detection impedance comprising a primary winding, a secondary winding and an output resistance connected with the secondary winding in parallel, wherein the primary winding has a magnetic core with high magnetic conductivity and high frequency response characteristics, and the primary winding is wound by metal of which the current-carrying capacity is above the preset one. Compared with the prior art, the detection impedance of the invention is suitable for high-pressure large-capacitance test objects, permits large measuring current and has high sensitivity.
Description
Technical field
The present invention relates to Partial Discharge Detection, relate in particular to a kind of detection impedance.
Background technology
Detecting impedance is an important sensing unit in the pulse current method measurement of partial discharge.The detection impedance of measurement of partial discharge appearance manufacturer product at present is only applicable to little electric capacity of high pressure or low pressure sample with large capacitance.Need carry out the on-the-spot measurement of partial discharge of high pressure sample with large capacitance based on the electrical production field requirement, propose new requirement, should reach big electric current, highly sensitive index detecting impedance.
Detect impedance and claim input block again, several kinds of resistance-type, resistance capacitance formula and resistance capacitance inductance types are arranged.Sensitivity, resolution characteristic and wave form varies that the kind of detection impedance and connected mode, position are detected partial discharge pulse are all influential.What common detection impedance was adopted is the resistance capacitance inductance type, adopts the double tunning input circuit of high-frequency transformer coupling between the primary and secondary coil.Its elementary winding electric sensibility reciprocal is mutually tuning with the equivalent capacity of hookup in the amplifier band of Partial discharge detector.When series process and multiple process, tuning capacitors can be by coupling capacitance C
KWith the test product capacitor C
XSeries value decide.When balancing method, (C when consistent as if two test product electric capacitys
X1=C
X2=C
X) then tuning capacitors can be by test product electric capacity C
XHalf calculate.
Detect the Partial Discharge Detection that impedance is used for low capacity equipment more at present; Concentrated ground capacitance like transformer is about 0.1～0.4 μ F, detects the through-flow 10A that is not more than of impedance during detection, and the electric capacity of mutual inductor is several thousand pF; The electric current that detects impedance of flowing through during detection is not more than 10A; Therefore detect impedance-tumed electric capacity C maximum magnitude also only at 0.4～6 μ F, all kinds of detection impedance parameters are seen Fig. 1, and it is an all kinds of detection impedance parameter table of the prior art.And the electric capacity of high-voltage parallel capacitor is about 30～50 μ F, does not improve as detecting impedance, and the sensitivity of detection will be very low, can't satisfy needs when surveying.In addition, when testing for the high-voltage parallel capacitor shelf depreciation, flow through detect impedance electric current all greater than 100A, only can through-flow 60A and detect the impedance maximum at present, damage and detect the impedance magnetic core because electric current is too big in the time of will causing testing, data can be inaccurate yet.
As shown in Figure 2, for prior art detects impedance scheme circuit theory synoptic diagram, it is little that it detects the impedance capacitive measurement scales, and elementary winding S is owing to usefulness is general lead, and through-current capability is low; The physical dimension of high-frequency transformer magnetic core A is little, generally selects diameter of phi=12mm～15mm, opening size 30mm * 15mm, and the magnetic core magnetic permeability is generally 800～1000 μ
0(u
0Be permeability of vacuum, u
0=4 π * 10
-7H/m), on the original structure basis, can't make the highly sensitive detection impedance of high capacity, must design again.
A way that solves the test of large capacity equipment shelf depreciation at present is to adopt the core-theaded type radio-frequency coil, and this punching coil is enclosed within by examination capacitor low-pressure side earth terminal, and the electric signal that utilizes the magnetic circuit coupling to come is judged inner shelf depreciation.
The core-theaded type radio-frequency coil since elementary be a circle, through-flow problem solves easily, selects the copper cash of suitable cross-section get final product, but because elementary be a circle lead, the very little L of equivalent inductance＜1 μ H, the tuning capacity of correspondence is very big, generally at 60～250 μ F.And the electric capacity test product scope of present field requirement is at 4～60 μ F.When test product electric capacity during greater than 60 μ F, it is very low to measure sensitivity, and scope is at 35～50pC, and this moment, on-the-spot control criterion to the power capacitor shelf depreciation was less than 50pC.This shows that this scheme signal to noise ratio (S/N ratio) is low, be difficult to satisfy detecting the requirement that should reach the high sensitivity index that impedance proposes.
Summary of the invention
Goal of the invention of the present invention is in order to solve the problem of the on-the-spot measurement of partial discharge of high pressure sample with large capacitance.
The embodiment of the invention provides a kind of detection impedance; Said detection impedance comprises elementary winding, secondary winding; An and output resistance parallelly connected with said secondary winding; Said elementary winding has high magnetic permeability high frequency sound characteristic magnetic core, and said elementary winding is selected the above metal coiling of predetermined current-carrying capacity for use.
Detection impedance according to the invention, preferable, said predetermined current-carrying capacity is more than the current-carrying capacity 100A.
Detection impedance according to the invention, preferable, the input end of said elementary winding links to each other with product to be tested electric capacity low pressure end, is used for the input pulse current signal; The output terminal that said detection impedance links to each other with said output resistance two ends links to each other with the measurement of partial discharge main frame, is used to export the pulsed current signal of handling through said detection impedance.
Detection impedance according to the invention, preferable, said elementary winding comprises first coil and second coil that is connected, the disjunct other end X of said first coil and second coil
1, X
3Link to each other with said product to be tested electric capacity low pressure end as input end respectively; And said first coil and second coil are all selected the above metal coiling of current-carrying capacity 100A for use; Wherein, The above metal of said current-carrying capacity 100A comprises the red copper bar of diameter 9mm, and the inductance value of the red copper bar of said diameter 9mm is 3～4 μ H.
Detection impedance according to the invention, preferable, said secondary winding comprises tertiary coil and the 4th coil that is connected, inductance value is 380 μ H.
Detection impedance according to the invention, preferable, part that said first coil links to each other with said second coil and the part that said the 4th coil links to each other with said output resistance also are connected and ground connection, and said earth terminal also links to each other with the shell of said detection impedance.
Detection impedance according to the invention, preferable, said first coil also is connected with input terminal X with the part that said second coil links to each other
2, said X
1, X
2, X
3All select the big current terminal of 600A for use.
Detection impedance according to the invention, preferable, the resistance value of said output resistance is 75 Ω.
Detection impedance according to the invention, preferable, the magnetic permeability of said high magnetic permeability high frequency sound characteristic magnetic core is 2000～3000 μ
0, wherein, u
0=4 π * 10
-7H/m; Frequency response is more than the 500kHz.
Detection impedance according to the invention, preferable, said high magnetic permeability high frequency sound characteristic magnetic core comprises high frequency U type ferrite core, is lined with non-magnetic media between the butt joint magnetic core of said high frequency U type ferrite core.
Detection impedance according to the invention, preferable, the diameter of said high frequency U type ferrite core is 22mm, opening size is 62mm * 25mm.
Detection impedance according to the invention, preferable, said output terminal links to each other with said measurement of partial discharge main frame through high frequency cable.
Compared with prior art, detection impedance of the present invention is suitable for high pressure high capacitance (4～60 μ F) test product, allow bigger measurement electric current (0～200A), have higher sensitivity and (can reach 8～10pC).
Description of drawings
Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, does not constitute qualification of the present invention.In the accompanying drawings:
Fig. 1 is an all kinds of detection impedance parameter table of the prior art;
Fig. 2 detects impedance scheme circuit theory synoptic diagram for prior art;
Fig. 3 detects impedance scheme circuit theory synoptic diagram for the embodiment of the invention;
Fig. 4 is the X among embodiment of the invention Fig. 3
1With X
3The synoptic diagram that is connected with product to be tested electric capacity low pressure end;
Fig. 5 is the high frequency U type ferrite core enlarged diagram among embodiment of the invention Fig. 3;
Fig. 6 is the Frequency Response curve map of the detection impedance among embodiment of the invention Fig. 3;
Fig. 7 is another detection impedance scheme circuit theory synoptic diagram of the embodiment of the invention.
Embodiment
For making the object of the invention, technical scheme and beneficial effect clearer,, the present invention is explained further details below in conjunction with embodiment and accompanying drawing.At this, exemplary embodiment of the present invention and explanation thereof are used to explain the present invention, but not as to qualification of the present invention.
Embodiment 1:
According to the basic demand of the on-the-spot measurement of partial discharge of high-voltage power capacitor, detect the impedance basic index and should reach through-flow 100A, input sensitivity should be less than 30pC in 20kHz～300kHz scope.
Embodiment of the invention Fig. 3 is the same with the detection impedance principle figure of prior art illustration 2, but the practical structures size, cross-sectional area of conductor, the magnetic core cross section, the core material characteristic is different.
Balance detection impedance input primary coil L
1And L
2The tuning capacity that inductance value and test loop are had is complementary.Corresponding capacitance range 4～60 μ F, L
1=L
2=3～4 μ H; Center resonant frequency is located near the intermediate value of tuning capacity scope; And try not to be selected near its two edges value; Because near the bigger rim value of electric capacity, will cause the reduction of sensitivity, and near the less rim value of electric capacity, possibly cause that the waveform generation of pulse is asymmetric.
The primary electrical sensibility reciprocal is a Low ESR to the voltage of power frequency supply; Because inductance value is less can to shield low-frequency disturbance and power-frequency voltage (the 50HZ voltage drop that power-frequency voltage finger to finger test power supply produces on primary coil through product to be tested), and low-frequency power is had enough anti-overload ability and good filtering characteristic.
Elementary winding Y (comprises L among Fig. 3
1And L
2) according to through-flow requirement, all need select the above metal coiling of current-carrying capacity 100A for use, can select diameter of phi=9mm red copper bar coiling for use, its current-carrying capacity can reach 200A～250A, X
1, X
2, X
3All select the big current terminal of 600A for use.As shown in Figure 4, be the X among embodiment of the invention Fig. 3
1With X
3The synoptic diagram that is connected with product to be tested electric capacity low pressure end.X during normal the measurement
1With X
3Respectively with test product electric capacity low pressure end C
X1, C
X2Be connected, lead-in wire is short as far as possible, to reduce spatial interference, X
2End is selected suitable cross section lead ground connection for use.
B is a high magnetic permeability high frequency sound characteristic magnetic core among Fig. 3, selects high-permeability material μ=2000～3000 μ for use
0, frequency response can reach more than the 500kHz, can select qualified high frequency U type ferrite core for use.As shown in Figure 5, be the high frequency U type ferrite core enlarged diagram among embodiment of the invention Fig. 3, between U type butt joint magnetic core, can fill up suitable non-magnetic media, be used for regulating L
1, L
2Inductance value, the physical dimension of magnetic core are diameter of phi=22mm, opening size 62mm * 25mm.L among the figure
3, L
4Be secondary winding.The inductance value of every winding is about 380 μ H, and R is a parallel connection output build-out resistor, and its resistance value is 75 Ω.
X
mOutput terminal links to each other with the measurement of partial discharge main frame through high frequency cable.
The O terminal is an earth terminal, links to each other with detection impedance screening can, prevents the electromagnetism clutter interference.
G is a discharging gap, prevents that high pressure is coupled to main frame low pressure and goes.
The detection impedance actual performance test result of the embodiment of the invention is as shown in Figure 6, and it is the Frequency Response curve map of the detection impedance among embodiment of the invention Fig. 3.Through using standard square-wave pulse calibrating device and PD meter joint test result to show: this detection impedance sensitivity reaches 8～10pC.The detection impedance frequency response characteristic result of the embodiment of the invention is illustrated in test frequency range 20-300kHz curve smoothing, compares through square wave in addition, and its sensitivity is higher, satisfies design demand.Should detect impedance and be integrated in the whole test loop, test result shows that the detection impedance of the embodiment of the invention can effectively differentiate product to be tested local discharge signal and external interference signals.
Detection impedance of the present invention is the significant element that local discharge signal detects in the discharge test loop, meets several kinds of detection method for local discharge (series process, multiple process, balancing method) that GB GB7354-87 is recommended.
Because putting to measure, high-voltage power capacitor office exist detection sensitivity low; Be prone to receive external interference; Problems such as test current is big, the apparent discharge capacity Δ q=C Δ U (discharge capacity of indication is the apparent discharge capacity in the measurement of partial discharge) that I is surveyed, directly and the size of electric capacity be directly proportional; So when the test product electric capacity was big, sensitivity reduced.Under this test condition, not only the basic noise of surveying instrument input stage is influential to sensitivity, and the interference voltage of in whole measuring system, responding to also can make sensitivity reduce.Measure for the office to the high capacitance high-voltage capacitor puts row at the scene, the balance bridge-type method that the above embodiment of the present invention is recommended detects the loop and has higher interference rejection capability, and decay disturbs multiple can reach 1: 20 to 1: 25.The detection impedance of the above embodiment of the present invention is suitable for high pressure high capacitance (4～60 μ F) test product, allows bigger measurement electric current (0～200A), and have higher sensitivity and (can reach 8～10pC).
Prior art detects impedance and allows through-flow only 50A, the about 15～20pC of sensitivity; And the above-mentioned detection impedance of the embodiment of the invention allows the through-flow 200A that reaches; Sensitivity reaches 8～10pC; Can satisfy 200kVar～500kVar; Six kinds of voltage (12kv in 5500V～12000V scope;
12/2kv; 11kv;
11/2kv) and three kinds of capacity (500kvar) combination has the on-the-spot partial discharge test of power capacitor of 18 kinds of specifications for 200kvar, 334kvar.
Embodiment 2:
It should be noted that elementary winding of the present invention and secondary winding also can be a coil, as shown in Figure 7, another detects impedance scheme circuit theory synoptic diagram for the embodiment of the invention, and its primary coil is L
1', secondary coil is L
2', wherein, said primary coil L
1' also select the above metal coiling of current-carrying capacity 100A for use.X
1' and X
3' be the detection impedance input end that is connected with product to be tested electric capacity low pressure end, X
1' and X
3' also all select the big current terminal of 600A for use.X
m' be the output terminal that links to each other with the measurement of partial discharge main frame through high frequency cable, also comprise and said secondary coil L
2' a parallelly connected output resistance R ', B ' is a high magnetic permeability high frequency sound characteristic magnetic core, also selects high-permeability material μ=2000～3000 μ for use
0, frequency response can reach the above magnetic core of 500kHz.O ' terminal is an earth terminal, links to each other with detection impedance screening can, prevents the electromagnetism clutter interference.
Through the detection impedance that the present invention succeeds in developing, make high-voltage power capacitor carry out measurement of partial discharge at the scene and be able to implement, solved gordian technique difficult problem in the measurement of partial discharge.Find successfully that through on-the-spot test many high-voltage power capacitor offices put exceed standard (defective), reliable assurance is provided for guaranteeing the power equipment safety operation.
Above-described embodiment; The object of the invention, technical scheme and beneficial effect have been carried out further explain, and institute it should be understood that the above is merely embodiment of the present invention; And be not used in qualification protection scope of the present invention; All within spirit of the present invention and principle, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (9)
1. one kind is detected impedance, and said detection impedance comprises elementary winding, secondary winding, and an output resistance parallelly connected with said secondary winding, it is characterized in that:
Said elementary winding has high magnetic permeability high frequency sound characteristic magnetic core, and said elementary winding is selected the above metal coiling of predetermined current-carrying capacity for use;
The magnetic permeability of said high magnetic permeability high frequency sound characteristic magnetic core is 2000～3000 μ
0, wherein, u
0=4 π * 10
-7H/m; Frequency response is more than the 500kHz;
Said high magnetic permeability high frequency sound characteristic magnetic core comprises high frequency U type ferrite core, is lined with non-magnetic media between the butt joint magnetic core of said high frequency U type ferrite core;
The diameter of said high frequency U type ferrite core is 22mm, and opening size is 62mm * 25mm.
2. detect impedance according to claim 1, it is characterized in that,
Said predetermined current-carrying capacity is more than the current-carrying capacity 100A.
3. detect impedance according to claim 1, it is characterized in that,
The input end of said elementary winding links to each other with product to be tested electric capacity low pressure end, is used for the input pulse current signal; The output terminal that said detection impedance links to each other with said output resistance two ends links to each other with the measurement of partial discharge main frame, is used to export the pulsed current signal of handling through said detection impedance.
4. like the said detection impedance of claim 2, it is characterized in that,
Said elementary winding comprises first coil and second coil that is connected, the disjunct other end X of said first coil and second coil
1, X
3Link to each other with said product to be tested electric capacity low pressure end as input end respectively; And said first coil and second coil are all selected the above metal coiling of current-carrying capacity 100A for use; Wherein, The above metal of said current-carrying capacity 100A comprises the red copper bar of diameter 9mm, and the inductance value of the red copper bar of said diameter 9mm is 3～4 μ H.
5. like the said detection impedance of claim 4, it is characterized in that,
Said secondary winding comprises tertiary coil and the 4th coil that is connected, and inductance value is 380 μ H.
6. like the said detection impedance of claim 5, it is characterized in that,
Part that said first coil links to each other with said second coil and the part that said the 4th coil links to each other with said output resistance also are connected and ground connection, and earth terminal also links to each other with the shell of said detection impedance.
7. like the said detection impedance of claim 6, it is characterized in that,
Said first coil also is connected with input terminal X with the part that said second coil links to each other
2, said X
1, X
2, X
3All select the big current terminal of 600A for use.
8. like the said detection impedance of claim 7, it is characterized in that,
The resistance value of said output resistance is 75 Ω.
9. like the said detection impedance of claim 3, it is characterized in that,
Said output terminal links to each other with said measurement of partial discharge main frame through high frequency cable.
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|---|---|---|---|
| CN2009100760969A CN101769947B (en) | 2009-01-05 | 2009-01-05 | Detection impedance |
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| CN112698124B (en) * | 2020-12-03 | 2023-07-14 | 成都宏明电子股份有限公司 | Method for judging whether polar medium dry type high-voltage capacitor accords with expected service life |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1719268A (en) * | 2005-08-04 | 2006-01-11 | 上海思源电气股份有限公司 | No partial discharge frequency conversion resonance experiment system |
| CN101004436A (en) * | 2007-01-22 | 2007-07-25 | 西南交通大学 | High senitive system for detecting local discharging of high voltage electric power equipment with large capacity |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1719268A (en) * | 2005-08-04 | 2006-01-11 | 上海思源电气股份有限公司 | No partial discharge frequency conversion resonance experiment system |
| CN101004436A (en) * | 2007-01-22 | 2007-07-25 | 西南交通大学 | High senitive system for detecting local discharging of high voltage electric power equipment with large capacity |
Non-Patent Citations (1)
| Title |
|---|
| 王昌长等.在线检测电力设备局部放电的电流传感器系统的研究.《电工技术学报》.1990,(第2期),42-46. * |
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Owner name: BEIJING HUAKE XINGSHENG ELECTRIC POWER ENGINEERING Free format text: FORMER OWNER: BEIJING HUAKE XINGSHENG ELECTRIC POWER ENGINEERING TECHNOLOGY CO., LTD. Effective date: 20121227 |
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Effective date of registration: 20121227 Address after: 100045 Beijing Fuxingmenwai Di Zang an Nan Xiang No. Patentee after: North China Electrical Power Research Institute LLC Patentee after: Beijing Huake Xingsheng Electric Power Engineering Technology Co., Ltd. Patentee after: State Grid Corporation of China Address before: 100045 Beijing Fuxingmenwai Di Zang an Nan Xiang No. Patentee before: North China Electrical Power Research Institute LLC Patentee before: Beijing Huake Xingsheng Electric Power Engineering Technology Co., Ltd. |