CN104090211A - Method for online detection of high impedance grounding fault of distributing line - Google Patents
Method for online detection of high impedance grounding fault of distributing line Download PDFInfo
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- CN104090211A CN104090211A CN201410338248.9A CN201410338248A CN104090211A CN 104090211 A CN104090211 A CN 104090211A CN 201410338248 A CN201410338248 A CN 201410338248A CN 104090211 A CN104090211 A CN 104090211A
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Abstract
The invention discloses a method for online detection of a high impedance grounding fault of a distributing line and belongs to the field of electric power system protection and control. According to the method, the zero-sequence voltage waveform within two to three periods after the high impedance grounding fault occurs is detected, the harmonic frequency spectrum of the waveform contains the fault information of high impedance grounding, and the method can be used for online detection of the high impedance grounding fault. The method comprises the steps of acquiring the zero-sequence voltage harmonic wave of the secondary side feeder line of a transformer, determining the fault feature harmonic frequency (between 1000 Hz and 5000 Hz usually) according to the topological structure of the line, and judging whether the high impedance grounding fault occurs on the line by detecting the amplitude and frequency of the harmonic wave. The method is especially suitable for small current grounding systems not over 10kV, and only zero-sequence voltage signal acquisition and analysis are needed. Compared with existing judging methods, the method has the advantages that information acquisition can be conducted more conveniently, sensitivity is higher, the high impedance grounding fault can be effectively distinguished from other working conditions and fault types, the occurrence of miss trip and incorrect trip is reduced, and identification is more accurate.
Description
Technical field
The invention belongs to protecting electrical power system and control field, particularly the detection method of a kind of low pressure for small current neutral grounding system (6 ~ 10kV) distribution line high resistance earthing fault.
Technical background
Singlephase earth fault is fault common in electric system, and itself does not have serious harmfulness, but very easily draws its more serious accident.From field failure analysis, find, in all phase-to phase faults, having quite a few is to be developed by singlephase earth fault.6 ~ 10kV distribution line is near user, and surrounding environment complexity, is easy to occur high resistance earthing fault, so get a good eye value for the on-line monitoring detection method of distribution line.Circuit generally adopts small current neutral grounding system, and when single-phase high resistance earthing fault occurs system, short-circuit current is little, and GPF (General Protection False is inoperative for this type of fault, is difficult to identification and detection, causes the fault initial stage to be difficult to be found.Even if most high resistance earthing faults are in short-term, can die away, but also have quite a few fault to be easily evolved into even more serious direct short-circuit fault.
Carry out on-line identification and the monitoring of power distribution network high resistance earthing fault, can find in time, in time early warning, in time location, process in time, be unlikely to develop into catastrophic failure, thereby eliminate potential faults, reduce the generation of power outage, ensure power supply continuity and power supply reliability.In addition, detect by the on-line monitoring to high resistance ground, can also carry out statistical study for the high resistance earthing fault of self-healing in short-term, determine high resistance earthing fault region occurred frequently, prevent in advance and process.Therefore, the research of high resistance earthing fault feature, from improving the angle of power distribution network operational reliability, is had to very important meaning.
Some characteristic quantities that are before mainly the voltage and current signal waveforms by obtaining for the research of high resistive fault carry out identification and the protection of high resistance earthing fault.Utilize the wavelet coefficient that the multiresolution analysis of fault-signal is produced to take absolute value and form the criterion of high resistive fault.But show that by the analysis of system this algorithm is for failure modes, stake resistance resistance, the information such as abort situation are all sharp not; The variation that proposes the energy of the even-order harmonic producing by monitoring zero-sequence current detects the method for high resistance earthing fault.High resistance earthing fault for fault current more than 5A has very high accuracy rate, but the range of application of this scheme is the transmission line of electricity based on 110kV and above, is difficult to use for distribution line.
Summary of the invention
Because the fault signature of the current single-phase high resistance earthing fault of low-voltage network is very not obvious, GPF (General Protection False is very undesirable with the discrimination method effect that is applied in voltage levels.The object of this invention is to provide a kind of online test method of transmission line of electricity high resistance earthing fault, determined faulty line characteristic harmonics according to the topological structure of circuit, harmonic frequency is conventionally between 1000 ~ 5000Hz, and amplitude reaches fundamental voltage amplitude 5% ~ 7%.Monitor the generation of single-phase high resistance earthing fault by characteristic harmonics frequency spectrum in detection failure line zero sequence voltage.
In order to reach above object, technical scheme of the present invention is: a kind of online test method of transmission line of electricity high resistance earthing fault, it is characterized in that, and comprise the following steps:
The online test method of described distribution line high resistance earthing fault, is characterized in that, comprises the following steps:
1) determine fault signature harmonic frequency according to line topological structure;
2) residual voltage of Circuit Fault on Secondary Transformer feeder line is carried out to on-line monitoring, obtain the sampled value F (n) of a cycle, n=1,2N, N is integer, value is 120 ~ 240;
3) by the fft analysis to sampled value sequence, draw analysis spectrum taking power-frequency voltage as first-harmonic;
4) whether checking there is frequency f
n: the characteristic harmonics amplitude of 1000 ~ 5000Hz reaches the spike Characteristics of Mutation of fundamental voltage amplitude 5% ~ 7%, if meet this high resistance earthing fault criterion, regards as high resistance earthing fault;
5) every 0.02 second repeats a step (1) ~ (4), obtains each cycle and whether occur the result of high resistance earthing fault.
The online test method of described distribution line high resistance earthing fault, in the time that single-phase high resistance earthing fault occurs, the harmonic wave producing in faulty line residual voltage waveform is carried out to spectrum analysis meeting discovery and can produce spike sudden change at a certain frequency place, according to different line topological structures, this frequency is between 1000 ~ 5000Hz.The failure message that has contained high resistance ground in this sudden change, this harmonic wave that frequency is the highest can be described as high resistive fault characteristic harmonics, and by this characteristic harmonics is analyzed, whether checking meets failure criterion, carries out the identification of fault with this.
The online test method of described distribution line high resistance earthing fault, the extraction of single-phase high resistance earthing fault characteristic harmonics need to utilize the online acquisition device of installing, the residual voltage collecting is carried out to real-time FFT spectrum analysis, extract the size of frequency, amplitude and the DC component of high resistive fault characteristic harmonics.
, for the spectrum analysis of high resistive fault characteristic harmonics, there is the criterion of high resistance earthing fault and be frequency and be between 1000 ~ 5000Hz, amplitude reaches fundamental voltage amplitude 5% ~ 7% in the online test method of described distribution line high resistance earthing fault.
The online test method of described distribution line high resistance earthing fault can be according to the form of the amplitude of high resistive fault characteristic harmonics and frequency spectrum, carries out the estimation of different stake resistance resistances.Determining that line topological structure obtains after line parameter circuit value, can determine that line fault characteristic harmonics amplitude is with fault resstance variation rule curve.Work as line failure, after determining and being high resistance earthing fault, can be taking this curve as reference value, the fault resstance of circuit being estimated.
The online test method of described distribution line high resistance earthing fault, can, according to the form of the amplitude of high resistive fault characteristic harmonics and frequency spectrum, carry out the estimation of fault phase angle and residual voltage instantaneous value.Determining that line topological structure obtains after line parameter circuit value, can determine that line fault characteristic harmonics form is with fault phase angle variation rule curve.There is single-phase high resistance earthing fault and determine after fault when picking out circuit, can be taking this curve as reference value, fault phase angle and the instantaneous voltage of circuit being estimated.
Compared with prior art, the beneficial effect of patent of the present invention is:
1) according to theory maturation, engineering reliability is high, identification analytical effect is stable, has overcome the unconspicuous weakness of signal characteristic for identification.
2) for realizing the surveying instrument equipment and technology maturation of discriminating function, overcome the shortcoming that is difficult to realization in actual production operational process.
3) can on the basis of Real-Time Monitoring, carry out statistical study to fault occurrence frequency, for line upkeep work provides reliable Data support and guiding suggestion.
Brief description of the drawings
Fig. 1 is that fault resistance of the present invention is the emulation pattern of 500 Ω high resistive fault characteristic harmonics frequency spectrums.
Fig. 2 be the present invention about characteristic harmonics amplitude with fault resstance Changing Pattern emulation pattern.
Embodiment
A kind of online test method embodiment of distribution line high resistance earthing fault is:
1) determine fault signature harmonic frequency according to line topological structure.
2) residual voltage of Circuit Fault on Secondary Transformer feeder line is carried out to on-line monitoring, obtains the sampled value f(n of a cycle), n=1,2N, N is integer, value is 120 ~ 240.
3) by sampled value sequence is carried out to fft analysis, draw analysis spectrum taking power-frequency voltage as first-harmonic.
4) whether checking there is frequency f
n: the characteristic harmonics amplitude of 1000 ~ 5000Hz reaches the spike Characteristics of Mutation of fundamental voltage amplitude 5% ~ 7%.If meet this criterion of high resistance earthing fault, regard as high resistance earthing fault.
5) harmonic amplitude that the characteristic harmonics amplitude recording according to faulty line and line topological structure obtain is with fault resstance Changing Pattern estimation fault resstance resistance.
6) harmonic amplitude that the characteristic harmonics spectrum morphology recording according to faulty line and line topological structure obtain is with fault resstance Changing Pattern estimation fault phase angle and instantaneous voltage.
Within every 0.02 second, repeat once above step.
The foregoing is only better embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any amendment of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (6)
1. an online test method for distribution line high resistance earthing fault, is characterized in that, comprises the following steps:
1) determine fault signature harmonic frequency according to line topological structure;
2) residual voltage of Circuit Fault on Secondary Transformer feeder line is carried out to on-line monitoring, obtain the sampled value F (n) of a cycle, n=1,2N, N is integer, value is 120 ~ 240;
3) by the fft analysis to sampled value sequence, draw analysis spectrum taking power-frequency voltage as first-harmonic;
4) whether checking there is frequency f
n: the characteristic harmonics amplitude of 1000 ~ 5000Hz, higher than the spike Characteristics of Mutation of fundamental voltage amplitude 5%, if meet this high resistance earthing fault criterion, is regarded as high resistance earthing fault;
5) every 0.02 second repeats a step (1) ~ (4), obtains each cycle and whether occur the result of high resistance earthing fault.
2. method as claimed in claim 1, it is characterized in that, when fault occurs, in faulty line residual voltage waveform harmonics frequency spectrum, can produce spike sudden change, in this sudden change, contain the failure message of high resistance ground, can be described as high resistive fault characteristic harmonics, by the analysis of this characteristic harmonics being carried out to the identification of fault.
3. method as claimed in claim 1, is characterized in that, utilizes the online acquisition device of installing, and the residual voltage collecting is carried out to real-time FFT spectrum analysis, extracts the size of frequency, amplitude and the DC component of high resistive fault characteristic harmonics.
4. method as claimed in claim 1, is characterized in that, for the analysis of high resistive fault characteristic harmonics, the criterion that high resistance earthing fault occurs is that frequency is, amplitude reaches fundamental voltage amplitude 5% ~ 7% between 1000 ~ 5000Hz.
5. method as claimed in claim 1, is characterized in that, according to the form of the amplitude of high resistive fault characteristic harmonics and frequency spectrum, can carry out the estimation of different stake resistance resistances.
6. method as claimed in claim 1, is characterized in that, according to the form of the amplitude of high resistive fault characteristic harmonics and frequency spectrum, can carry out the estimation of fault phase angle and residual voltage instantaneous value.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104316791A (en) * | 2014-10-21 | 2015-01-28 | 国家电网公司 | Reason analyzing and locating method for high resistance grounding fault of transmission line |
| CN106597222A (en) * | 2016-12-16 | 2017-04-26 | 湖北省超能超高压电力科技开发有限公司 | Transmission line overvoltage fault type identification method based on ground line current |
| CN109001593A (en) * | 2018-07-16 | 2018-12-14 | 北京映翰通网络技术股份有限公司 | A kind of distribution network failure recording control method |
| CN110108972A (en) * | 2019-06-26 | 2019-08-09 | 云南电网有限责任公司电力科学研究院 | A kind of arc method for measuring of single-phase high-impedance |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100334458C (en) * | 2005-06-02 | 2007-08-29 | 昆明理工大学 | Malfunction route selection method for resonant grounded system based on current decomposition and wattles detection |
| CN101187687B (en) * | 2007-12-21 | 2010-09-08 | 清华大学 | High resistance earthing fault detection method based on transient traveling wave |
| CN101482593A (en) * | 2008-12-25 | 2009-07-15 | 南京因泰莱配电自动化设备有限公司 | Low-current grounding intelligent route selection method and apparatus |
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2014
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104316791A (en) * | 2014-10-21 | 2015-01-28 | 国家电网公司 | Reason analyzing and locating method for high resistance grounding fault of transmission line |
| CN106597222A (en) * | 2016-12-16 | 2017-04-26 | 湖北省超能超高压电力科技开发有限公司 | Transmission line overvoltage fault type identification method based on ground line current |
| CN106597222B (en) * | 2016-12-16 | 2019-06-11 | 湖北省超能超高压电力科技开发有限公司 | A kind of transmission line of electricity overvoltage fault type recognition method based on ground line current |
| CN109001593A (en) * | 2018-07-16 | 2018-12-14 | 北京映翰通网络技术股份有限公司 | A kind of distribution network failure recording control method |
| CN110108972A (en) * | 2019-06-26 | 2019-08-09 | 云南电网有限责任公司电力科学研究院 | A kind of arc method for measuring of single-phase high-impedance |
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