CN103018630A - Single-phase earth fault transient line selection method of distribution network - Google Patents
Single-phase earth fault transient line selection method of distribution network Download PDFInfo
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Abstract
The invention relates to a method for detecting faults in an electric cable, a transmission wire or a network, and in particular relates to a single-phase earth fault transient line selection method of a distribution network, which, using the group amplitude-comparison phase-comparison idea in a power current as a reference, forms a group amplitude-comparison phase-comparison line selection method of transient currents, to compare the amplitudes of the transient currents of all outgoing lines, select a line with the comparatively great amplitude and compare the polarity to determine the line in fault; and furthermore, the earth fault of a bus can be determined depending on a judgment on the polarity of the transient current. The single-phase earth fault transient line selection method of the distribution network disclosed by the invention has the advantages of strong anti-jamming ability, high line selection success rate and wide application range; and keeping the advantages of passive line selection, the method is comparatively high in safety, convenient in construction, capable of installing and maintaining in an un-interruptible manner.
Description
Technical field
The present invention relates to the method for the fault in a kind of exploration cable, transmission line or the network, particularly a kind of distribution singlephase earth fault transient state selection method.
Background technology
Single-phase earthing is the primary failure mode of power distribution network, accounts for about 80% of fault sum, and as considering higher, the easy uncared-for instantaneity earth fault of occurrence frequency, its shared ratio is just higher.When medium voltage distribution network breaks down, definite faulty line (failure line selection) that need to carry out, determine abort situation (localization of fault), the automatism isolation of fault section (adaptive trip), purpose be the excision fault, avoid having a power failure or reducing frequency of power cut and power off time, improve power supply reliability.
The failure line selection technology is divided into early stage isolated neutral system route selection technology, compensated distribution network route selection technology and recent new technology.Early stage small current neutral grounding system mostly is earth-free mode, and its failure line selection product is also many based on the amplitude of simple fault power frequency zero-sequence current or based on simple current direction (polarity) relation principle, but the route selection effect is still not good.For example: the out-of-limit method of amplitude: take this line-to-ground zero sequence capacitance current as threshold, be defined as faulty line when the fault zero-sequence current surpasses threshold, shortcoming is that detection sensitivity is low.The colony amplitude comparison phase comparing method: the fault current to all outlets compares first amplitude, selects larger its polarity of circuit comparison of amplitude to determine faulty line, and it is effective to compare simple amplitude relative method, polarity comparison, but still is not suitable for the scene 2 wire system.Electric current (power) direction method: the phase relation of alternative route fault power frequency zero-sequence current and residual voltage when electric current (power) is defined as faulty line when flowing to bus, does not need other line information that the property of posing as is arranged, applicable scene 2 wire system.
Compensated distribution network route selection technology is to utilize harmonic component in the fault current and real component to realize the method for route selection, yet because the harmonic current that fault produces not only depends on the size that has or not harmonic source and harmonic source in the system, the phase relation between each harmonic source, also with abort situation close relationship is arranged, the harmonic content amplitude in the fault current less (being generally less than 10%) and unstable.It is subject to arc grounding and intermittent grounding fault impact simultaneously, and detection sensitivity is low, and practical application effect is undesirable, is progressively abandoned.
Described new technology refers to active selection method, utilizes the action of special-purpose primary equipment or other primary equipment to cooperate and changes the larger power frequency extra current of primary system running status generation, perhaps utilizes signal injection equipment to inject particular current signal in system.Active route selection technology can comprise signal injection method, remnant current increment method, middle electric-resistivity method, linear perturbation theory etc.Its general implementation is: (1) transformer station terminal monitoring residual voltage signal, after earth fault occurs and continuing to surpass certain hour, confirm as the continuous earth fault, adjust equipment state or to system's Injection Signal; (2) line selection apparatus is monitored each outlet current signal, and selecting the circuit of power current amplitude increment or Injection Current signal maximum is faulty line.The route selection effect of active method all more early stage technology is significantly improved.The route selection success ratio of part technology and equipment can reach 85% ~ 95%, yet this Technology Need injects signal specific toward electrical network, and needs other high pressure primary equipment actions to cooperate, and therefore has certain potential safety hazard.
Summary of the invention
The object of the invention is to provides a kind of route selection success ratio height, wide adaptability, safe distribution singlephase earth fault transient state selection method according to the deficiencies in the prior art part.
The objective of the invention is to realize by following approach:
Distribution singlephase earth fault transient state selection method, its main points are, comprise the steps:
(1) provides a kind of zero sequence voltage detection unit, detect the residual voltage value, when the change of residual voltage value, then start the route selection program;
(2) provide a kind of data acquisition unit, the transient current value i of every line outlet in its Real-time Collection setting regions
0k(t),
(3) provide a kind of data processing unit, the transient current value i that its reception collects
0k(t), and carry out computing: with i
0k(t) carry out transformation calculations, to obtain its amplitude I
0k, wherein:
(4) further each the transient current amplitude that obtains is compared processing, obtain the I of transient current amplitude maximum
0k, the corresponding line marker of this maximum transient current amplitude is the pre-service faulty line;
(5) the further coefficient of comparisons P that calculates the outlet transient current polarity of pre-service faulty line in data processing unit
Km:
(6) work as P
Km0 show i
0k(t) and i
0m(t) same polarity returns to step (2); Work as P
Km＜0 shows i
0k(t) and i
0m(t) reversed polarity, this moment, this pre-service faulty line was labeled as faulty line, and stored.
All there is transition (transient state) process in electric system between any two stable states, can produce abundant transient signal.For low current grounding, than the power frequency steady-state current that fault produces, it is especially strong that its transient process just seems, its fault transient state current amplitude also seems especially large accordingly, and maximum can reach hundreds of amperes.Therefore, the transient signal that produces during the utilisation system fault carries out route selection.In the regional power grid, the zero-sequence current of fault upstream, trouble spot (bus bar side) check point perfects line-to-ground capacitance current and this check point to line distribution capacitance electric current sum between the bus for all, its zero-sequence current constantly increases with the increase amplitude to the bus distance from line flows to bus.Generally speaking, its zero-sequence current amplitude of check point near the trouble spot is maximum in the whole system.For the zero-sequence current of each line outlet, faulty line amplitude maximum (equal all and perfect the circuit sum), flow to (polarity) and perfect circuit opposite, there is obvious fault signature, therefore be used for the realization failure line selection.
Because simple transient current amplitude relative method can cause falsely dropping when busbar grounding, and simple transient current polarity comparison exists shortly when perfecting circuit, and small-signal very easily is interfered impact and falsely drops.Therefore the colony amplitude comparison in the needs reference power current is than phase thinking, and the colony amplitude comparison of structure transient current is than phase selection method.That is, to the first amplitude relatively of the transient current of all outlets, select the larger circuit of amplitude more relatively its polarity determine faulty line.
Therefore distribution singlephase earth fault transient state selection method of the present invention has following technical characterstic: because the transient current amplitude is large (generally greater than 100A, cross zero failure and still have obvious transient signal), therefore antijamming capability is strong, the route selection success ratio is high, not affected by unstable arc, and detect when arc grounding and intermittent ground connection more reliable; Wide adaptability, not affected by arc suppression coil, applicable to earth-free, through grounding through arc with through the high resistance ground system, and overhead transmission line or cable line, also applicable cable aerial mixed line, zero-sequence current can obtain by common zero sequence CT, also can be synthetic by three-phase CT, and the distribution system of applicable various electric pressures; The advantage of continuity passive type route selection namely has higher security, only accesses voltage signal and current signal, not additional other high pressure primary equipment does not need other primary equipment to cooperate yet, and primary system is had no effect, and construction is convenient, can not have a power failure to install and maintenance.
The present invention can further be specially:
Work as P
Km0, then will set in the formula of transient current value substitution polarity coefficient of comparisons of the All other routes in the zone, if the polarity of all circuits is identical, then represent the busbar grounding fault, bus is labeled as faulty line, and stores.
Like this, just can detect the situation of busbar grounding fault, avoid the problem of falsely dropping that when the busbar grounding fault, produces fully.
The every cycle sampling number of data acquisition unit is greater than 100 points.
Because for stable earth fault, the transient state process duration is lacked (generally within 2ms), needs device to have the real-time sampling ability, and the transient signal frequency is high simultaneously, device will have higher sampling rate, and every cycle sampling number should be greater than 100 degree of accuracy that can enough guarantee data.
In sum, the invention provides a kind of distribution singlephase earth fault transient state selection method, colony amplitude comparison in the reference power current is than phase thinking, the colony amplitude comparison of structure transient current is than phase selection method, transient current to all outlets compares first amplitude, selects the larger circuit of amplitude to compare its polarity again and determines faulty line.It is advantageous that antijamming capability is strong, the route selection success ratio is high, wide adaptability; The advantage of continuity passive type route selection has higher security, and construction is convenient, can not have a power failure and install and maintenance.
Specific embodiment
Most preferred embodiment:
Distribution singlephase earth fault transient state selection method comprises the steps:
(1) provides a kind of zero sequence voltage detection unit, detect the residual voltage value, when the change of residual voltage value, then start the route selection program;
(2) provide a kind of data acquisition unit, the transient current value i of every line outlet in its Real-time Collection setting regions
0k(t), the every cycle sampling number of data acquisition unit is greater than 100 points;
(3) provide a kind of data processing unit, the transient current value i that its reception collects
0k(t), and carry out computing: with i
0k(t) carry out transformation calculations, to obtain its amplitude I
0k, wherein:
(4) further each the transient current amplitude that obtains is compared processing, obtain the I of transient current amplitude maximum
0k, the corresponding line marker of this maximum transient current amplitude is the pre-service faulty line;
(5) the further coefficient of comparisons P that calculates the outlet transient current polarity of pre-service faulty line in data processing unit
Km:
(6) work as P
Km0 show i
0k(t) and i
0m(t) same polarity then will set in the formula of transient current value substitution polarity coefficient of comparisons of the All other routes in the zone, if the polarity of all circuits is identical, then represent the busbar grounding fault, bus is labeled as faulty line, and store;
(7) work as P
Km＜0 shows i
0k(t) and i
0m(t) reversed polarity, this moment, this pre-service faulty line was labeled as faulty line, and stored.
On hardware configuration: form low-current ground fault line selection device by zero sequence voltage detection unit, data acquisition unit and data processing unit and communication unit, provide FTU to be installed on each check point place of circuit as the direct-detection equipment of fault, it is communicated by letter with positioning master station by finite element networks such as the wireless networks such as GPRS/CDMA or power optical fiber private networks with line selection apparatus, and positioning master station is installed on control center.
Low-current ground fault line selection device is pressed bus grouping access bus three-phase voltage, bus residual voltage and circuit zero-sequence current, during system single-phase earth fault, finish the data acquisition-and-recording of bus three-phase voltage, bus residual voltage and circuit transient current, and with the data upload main control system that records, after the main control system route selection result is exported by the switching value of device.
Main control system uses Windows operating system, operation low current grounding analytic system software on it, this software is mainly finished collection, the storage of low-current ground fault line selection device record data, the demonstration of fault waveform, real-time automatic route selection and the result shown, reports, can accurately realize fault forecast, route selection, select phase.
Main control system can also serve as data server simultaneously, for the long-range fault data that reads in the transformer station.
When low current grounding occured, line selection apparatus gathered the residual voltage at bus place and the transient state zero mould electric current of each outlet, utilizes the methods such as amplitude, polarity, power direction to determine faulty line, and it is reported positioning master station by communication network.The voltage that FTU produces respectively according to phase fault and low current grounding, the power frequency in the current signal and the feature of transient state component report to the automatic station-keeping system main website with failure message by communication network.Positioning master station is determined first faulty line according to the result of line selection apparatus, and the result who reports according to FTU again determines the guilty culprit section.
It is same as the prior art that the present invention does not state part.
Claims (3)
1. distribution singlephase earth fault transient state selection method is characterized in that, comprises the steps:
(1) provides a kind of zero sequence voltage detection unit, detect the residual voltage value, when the change of residual voltage value, then start the route selection program;
(2) provide a kind of data acquisition unit, the transient current value i of every line outlet in its Real-time Collection setting regions
0k(t),
(3) provide a kind of data processing unit, the transient current value i that its reception collects
0k(t), and carry out computing: with i
0k(t) carry out transformation calculations, to obtain its amplitude I
0k, wherein:
(4) further each the transient current amplitude that obtains is compared processing, obtain the I of transient current amplitude maximum
0k, the corresponding line marker of this maximum transient current amplitude is the pre-service faulty line;
(5) the further coefficient of comparisons P that calculates the outlet transient current polarity of pre-service faulty line in data processing unit
Km:
(6) work as P
Km0 show i
0k(t) and i
0m(t) same polarity returns to step (2); Work as P
Km＜0 shows i
0k(t) and i
0m(t) reversed polarity, this moment, this pre-service faulty line was labeled as faulty line, and stored.
2. distribution singlephase earth fault transient state selection method according to claim 1 is characterized in that, works as P
Km0, then will set in the formula of transient current value substitution polarity coefficient of comparisons of the All other routes in the zone, if the polarity of all circuits is identical, then represent the busbar grounding fault, bus is labeled as faulty line, and stores.
3. distribution singlephase earth fault transient state selection method according to claim 1 is characterized in that, the every cycle sampling number of data acquisition unit is greater than 100 points.
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| CN103487724A (en) * | 2013-09-12 | 2014-01-01 | 国家电网公司 | Single-phase ground fault positioning method of power distribution network |
| WO2015161651A1 (en) * | 2014-04-24 | 2015-10-29 | 江苏省电力公司常州供电公司 | Adaptive monitoring method for grounding current of power cable |
| CN106405330A (en) * | 2016-08-31 | 2017-02-15 | 广西电网有限责任公司电力科学研究院 | Transient current projection component polarity comparison-based fault line selection method |
| CN106443330A (en) * | 2016-09-07 | 2017-02-22 | 中国石油大学(华东) | Small current grounding system high-resistance grounding fault line selection method based on comparison between transient projection component amplitude and polar relationship |
| CN106443349A (en) * | 2016-10-17 | 2017-02-22 | 国网福建省电力有限公司 | High-resistance ground fault positioning method and system |
| CN106526410A (en) * | 2016-09-07 | 2017-03-22 | 中国石油大学(华东) | Small-current grounding system high-resistance grounding fault positioning method based on transient current projection component amplitude comparison |
| CN106908695A (en) * | 2017-03-15 | 2017-06-30 | 济南置真电气有限公司 | A kind of singlephase earth fault logic decision method based on divide-shut brake information |
| CN106990320A (en) * | 2017-02-24 | 2017-07-28 | 新疆电力建设调试所 | A kind of microgrid, micro-grid system and microgrid Fault Locating Method |
| CN107589347A (en) * | 2017-10-19 | 2018-01-16 | 成都汉度科技有限公司 | Single-phase earth fault discrimination method based on transient zero-sequence current |
| CN107843804A (en) * | 2017-10-19 | 2018-03-27 | 成都汉度科技有限公司 | Method based on FTU and that fault detector realizes fault location |
| CN109884471A (en) * | 2019-03-22 | 2019-06-14 | 张安斌 | Phasor product has works to judge failure phase and selection method |
| CN110426596A (en) * | 2019-09-11 | 2019-11-08 | 山东职业学院 | A kind of Distributed power line single phase grounding failure Section Location |
| CN111141995A (en) * | 2020-01-17 | 2020-05-12 | 中国电力科学研究院有限公司 | Line double-end steady-state distance measuring method and system based on amplitude comparison principle |
| CN111521912A (en) * | 2020-06-05 | 2020-08-11 | 国网江西省电力有限公司鹰潭供电分公司 | Distributed fault line selection method |
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| CN103487724A (en) * | 2013-09-12 | 2014-01-01 | 国家电网公司 | Single-phase ground fault positioning method of power distribution network |
| US10352981B2 (en) | 2014-04-24 | 2019-07-16 | Chang Zhou Current Supply Company Of Jiangsu Electric Power Company | Power-cable ground current self-adaptive monitoring method |
| WO2015161651A1 (en) * | 2014-04-24 | 2015-10-29 | 江苏省电力公司常州供电公司 | Adaptive monitoring method for grounding current of power cable |
| CN106405330A (en) * | 2016-08-31 | 2017-02-15 | 广西电网有限责任公司电力科学研究院 | Transient current projection component polarity comparison-based fault line selection method |
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| CN107589347A (en) * | 2017-10-19 | 2018-01-16 | 成都汉度科技有限公司 | Single-phase earth fault discrimination method based on transient zero-sequence current |
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| CN109884471A (en) * | 2019-03-22 | 2019-06-14 | 张安斌 | Phasor product has works to judge failure phase and selection method |
| CN109884471B (en) * | 2019-03-22 | 2020-12-11 | 张安斌 | Phasor product active method for judging fault phase and selecting line |
| CN110426596A (en) * | 2019-09-11 | 2019-11-08 | 山东职业学院 | A kind of Distributed power line single phase grounding failure Section Location |
| CN111141995A (en) * | 2020-01-17 | 2020-05-12 | 中国电力科学研究院有限公司 | Line double-end steady-state distance measuring method and system based on amplitude comparison principle |
| CN111141995B (en) * | 2020-01-17 | 2022-10-04 | 中国电力科学研究院有限公司 | Line double-end steady-state distance measuring method and system based on amplitude comparison principle |
| CN111521912A (en) * | 2020-06-05 | 2020-08-11 | 国网江西省电力有限公司鹰潭供电分公司 | Distributed fault line selection method |
| CN114089098A (en) * | 2021-10-25 | 2022-02-25 | 珠海许继电气有限公司 | Power distribution network fault type identification method and device |
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Application publication date: 20130403 |