A kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization method

文档序号:1754429 发布日期:2019-11-29 浏览:4次 中文

阅读说明:本技术 一种小电流接地电网单相间歇性电弧接地故障定位方法 (A kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization method ) 是由 聂宇 张新宇 赵丹 王雅楠 赵传宗 杜威 王诗清 刘垣彤 赵孟臣 姜君 赵凤琦 于 2019-07-01 设计创作,主要内容包括:本发明公开了一种小电流接地电网单相间歇性电弧接地故障定位方法,即对电弧燃烧状态进行检测,捕捉电弧重燃时刻并在电弧重燃初期立刻注入扰动信号,使间歇性电弧转为稳定电弧,从而在故障相成功注入扰动信号,此时通过故障指示器的指示情况可以辨别故障线路与非故障线路,同时确定故障区域。该方法与随机注入扰动信号相比有如下优点:避免了在电弧熄灭期间注入扰动信号的无效性,同时避免了电弧熄灭期间注入扰动信号导致故障相电压升高造成电弧重燃,不会额外加重系统过电压负担;在电弧燃烧期间注入扰动信号,故障电流的增大有利于促使间歇性电弧向稳定电弧转化,减小间歇性电弧的危害同时提高故障定位的有效性。(The invention discloses a kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization methods, arc burning state is detected, it captures the arc reignition moment and injects disturbing signal at once at arc reignition initial stage, intermittent electric arc is set to switch to stablize electric arc, to mutually successfully inject disturbing signal in failure, faulty line and non-fault line can be distinguished by the instruction situation of fault detector at this time, while determining fault zone.This method has the following advantages compared with injection disturbing signal at random: avoiding the ineffectivity that disturbing signal is injected during arc extinction, disturbing signal is injected during avoiding arc extinction simultaneously causes faulted phase voltage raising to cause arc reignition, will not additional heavy system overvoltage burden;Disturbing signal is injected during arc burning, the increase of fault current is conducive to promote intermittent electric arc to electric arc conversion is stablized, reduces the harm of intermittent electric arc while improving the validity of fault location.)

1. a kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization method, step include:

The phase voltage data on substation bus bar are acquired, singlephase earth fault is judged whether there is;

After detecting the presence of singlephase earth fault and determining failure phase, between being determine whether by intermittent electric arc discrimination method Having a rest property arcing ground;

If it is determined that for when being, by restriking the moment for faulted phase voltage Feature capturing intermittence electric arc, in failure phase busbar voltage The mutation moment injects disturbing signal next time, if it is determined that being directly injected into disturbing signal when being no;

Faulted phase current increases within disturbing signal injection period, determines fault zone with this.

2. according to the method described in claim 1, wherein, intermittent electric arc discrimination method step includes: to utilize wavelet transformation point Failure phase busbar voltage is solved, the scale of wavelet decomposition is selected according to sample frequency, records setting time interval internal fault phase voltage It is mutated number, when mutation number is greater than the set value, is determined as intermittent arcing ground.

3. method according to claim 1 or 2, wherein the method at the moment of restriking for capturing intermittent electric arc is root 6 layers of decomposition are done to faulted phase voltage signal according to using DB6 wavelet transformation, the high frequency coefficient d3 by the 3rd layer judges arc burning When caused by voltage jump, d3 coefficient uprushes, and d3 coefficient is exactly the arc reignition moment at the time of breaking through threshold value.

4. according to the method described in claim 1, wherein, on bus be parallel with ground signalling source device, ground signalling source device Including three groups of switching devices for being sequentially connected in series ground connection, resistors, change the parallel resistance of non-faulting phase to increase fault current.

5. according to the method described in claim 4, wherein, the method for the injection disturbing signal is control ground signalling source dress It sets, the switching device on bus by selecting phase makes resistance-grounded system.

6. method according to claim 4 or 5, it is characterised in that: the switching device is fast power electronic switch.

7. according to the method described in claim 1, it is characterized by: the step of determining fault zone further includes combined circuit The instruction situation of topological structure and fault detector realizes fault location.

Technical field

The present invention relates to power failure detection technique fields, and in particular to a kind of low current neutral grounding electric network single phase intermittent electricity Arc Earth design method.

Background technique

China's 6~35kV medium voltage distribution network mostly uses neutral non-effective grounding mode, occurs in system operation In failure, the ratio highest of singlephase earth fault generation.Due to the failure that distribution net work structure is complicated and singlephase earth fault generates Electric current is smaller, and certain difficulty is caused to fault location.At present for the fault location in the case of power distribution network single-phase earthing, It is proposed many theoretical methods, while many devices have put into live operation.

The Fault Locating Method proposed at present, which mainly has, to be positioned using fault-signal and positions two greatly by Injection Signal Class.When single phase intermittent arcing ground occurs for system, repeat arcing and blow-out process in the short time, the process it is not true The qualitative best opportunity for making Injection Signal is difficult to determine, and extinguish repeatedly, complicated transient signal that Reignition Process generates is to failure Signal framing brings serious interference.The patent of Publication No. CN106324430A proposes a kind of parallel resistance disturbing signal Fault locator, i.e. failure are alternately in parallel resistance as disturbing signal, on fault point in non-faulting at bus after occurring Corresponding disturbing signal can be detected in trip test point.(neat Zheng, Zhuan Shuyi, Liu Zifa, Yao Zhizhang, Zhang Yu stick up and are based on simultaneously document 1 The electrical power distribution network fault location method for joining resistance disturbing signal analyzes [J] Automation of Electric Systems, 2018,42 (09): 195- 200.DOI:10.7500/AEPS20170817005.) improved method to the device is proposed, it proposes to combine connecing for neutral point Ground situation is only mutually injected disturbing signal to the leading phase of failure phase or lag, but still is mainly believed using the stable state after single-phase earthing Number.It, can not be in event if at the time of parallel resistance being the gap that electric arc temporarily extinguishes in single phase intermittent arcing ground Hinder route and injects disturbing signal, fault location failure.

Summary of the invention

Therefore, the purpose of the present invention is to overcome the defects in the prior art, and it is single-phase to provide a kind of low current neutral grounding electric network Intermittent arc-earth fault localization method realizes that the discrimination to fault zone positions.

To achieve the goals above, technical scheme is as follows:

A kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization method, step include: acquisition substation Phase voltage data on bus, judge whether there is singlephase earth fault;It detects the presence of singlephase earth fault and determines failure After phase, intermittent arcing ground is determine whether by intermittent electric arc discrimination method;If it is determined that passing through failure phase for when being Voltage characteristic captures restriking the moment for intermittent electric arc, is mutated moment injection disturbing signal next time in failure phase busbar voltage, If it is determined that being directly injected into disturbing signal when being no;Faulted phase current increases within disturbing signal injection period, determines failure with this Region.

Preferably, above-mentioned intermittent electric arc discrimination method step includes: to decompose failure phase bus electricity using wavelet transformation Pressure, the scale of wavelet decomposition is selected according to sample frequency, and record setting time interval internal fault phase voltage is mutated number, works as mutation When number is greater than the set value, it is determined as intermittent arcing ground.

Preferably, the method at the moment of restriking of the intermittent electric arc of above-mentioned capture is according to utilization DB6 wavelet transformation to event Barrier phase voltage signal does 6 layers of decomposition, when judging arc burning by the 3rd layer of high frequency coefficient d3 caused by voltage jump, d3 system Number is uprushed, and d3 coefficient is exactly the arc reignition moment at the time of breaking through threshold value.

Preferably, ground signalling source device is parallel on above-mentioned bus, ground signalling source device includes three groups and is sequentially connected in series Switching device, the resistor of ground connection change the parallel resistance of non-faulting phase to increase fault current.

Preferably, the method for above-mentioned injection disturbing signal is to control ground signalling source device, on the bus by selecting phase Switching device make resistance-grounded system.

Preferably, the step of above-mentioned determination fault zone further includes combined circuit topological structure and fault detector Indicate that situation realizes fault location.

Preferably, above-mentioned switching device is fast power electronic switch.

This programme connects according to the electrical power distribution network fault location method based on parallel resistance disturbing signal in single phase intermittent electric arc Positional uncertainty problem in earth fault, proposes a kind of improved method, i.e., detects to arc burning state, captures electricity Arc is restriked the moment and injects disturbing signal at arc reignition initial stage at once, and this method has as follows compared with injection disturbing signal at random Advantage:

1) ineffectivity for injecting disturbing signal during arc extinction is avoided, while being injected during avoiding arc extinction Disturbing signal causes faulted phase voltage raising to cause arc reignition, will not additional heavy system overvoltage burden.

2) disturbing signal is injected during arc burning, the increase of fault current is conducive to promote intermittent electric arc to stabilization Electric arc conversion reduces the harm of intermittent electric arc while improving the validity of fault location.

3) make intermittent electric arc switch to stablize electric arc, to mutually successfully inject disturbing signal in failure, pass through failure at this time The instruction situation of indicator can distinguish faulty line and non-fault line, while determine fault zone.

Detailed description of the invention

Fig. 1 is the flow chart of Fault Locating Method provided by the invention;

Fig. 2 is the distribution network line schematic diagram in the embodiment of the present invention;

Fig. 3 is the chugging arc waveform in the embodiment of the present invention;

Fig. 4 injects the faulted phase current waveform diagram of disturbing signal during being the blow-out in the embodiment of the present invention;

Fig. 5 injects the faulted phase current waveform diagram of disturbing signal during being the arcing in the embodiment of the present invention;

Fig. 6 is the ground signalling source device schematic diagram in the embodiment of the present invention.

Specific embodiment

Below by way of the drawings and specific embodiments, the present invention is described in further detail.

As shown in Figure 1, a kind of low current neutral grounding electric network single phase intermittent arc-earth faults positioning side provided by the invention Method, step include: to acquire the phase voltage data of substation bus bar, judge whether there is singlephase earth fault;Detect the presence of list After phase ground fault and determining failure phase, selected using DB6 wavelet decomposition failure phase busbar voltage, and according to actual samples frequency The scale of wavelet decomposition is selected, record Δ t time interval internal fault phase voltage is mutated times N;When N is less than setting value Nset, directly Connect injection disturbing signal;When N is greater than the set value Nset, it is determined as intermittent arcing ground, is caught by faulted phase voltage feature Restriking the moment for intermittent electric arc is caught, is mutated moment injection disturbing signal, faulted phase current next time in failure phase busbar voltage Increase within disturbing signal injection period, fault zone is determined with this, if positioning failure, repeats to dash forward next time in busbar voltage Become moment injection disturbing signal.

The method at the moment of restriking of the intermittent electric arc of above-mentioned capture is according to utilization DB6 wavelet transformation to faulted phase voltage Signal does 6 layers of decomposition, when judging arc burning by the 3rd layer of high frequency coefficient d3 caused by voltage jump, d3 coefficient uprushes, d3 Coefficient is exactly the arc reignition moment at the time of breaking through threshold value.

Ground signalling source device is parallel on above-mentioned bus as shown in fig. 6, ground signalling source device is successively gone here and there including three groups Couple switching device, the resistor on ground, switching device is fast power electronic switch, changes the parallel resistance of non-faulting phase to increase Major break down electric current.

The method of above-mentioned injection disturbing signal is control ground signalling source device, the derailing switch on bus by selecting phase Part makes resistance-grounded system.

The step of above-mentioned determination fault zone further includes the instruction feelings of combined circuit topological structure and fault detector Condition realizes fault location.

Simulating, verifying is carried out according to distribution network line schematic diagram as shown in Figure 2, in the case where intermittent arcing ground, Arc burning and the characteristic of extinguishing are very big to the availability influence of injection disturbing signal localization method, it is therefore desirable to establish accurate Intermittent Arc Modelling.Classical Arc Modelling mainly includes Mayr model, Cassie model and based on different assumed conditions Improve Mayr model.Cassie model is suitable for arc gap low resistance state before simulation arc current zero passage, and Mayr model is suitable for Arc gap high resistance state after simulating arc current zero passage.Need to study herein extinguishing of the intermittent electric arc after current over-zero with And state of restriking, sunykatuib analysis, electric arc equation such as formula (1) are carried out using Mayr model.

In formula: gmFor electric arc dynamic conductivity;E is arc column electric field strength;I is arc gap electric current;τmFor arc duration constant; plossFor arc column dissipated power, plossIt also is constant.

It is built using the TACS control resistance, numerical integration element, comprehensive mathematics element etc. of TACS module in EMTP software Mayr Arc Modelling, and applied to carry out the emulation of single phase intermittent arcing ground in 10kV isolated neutral power distribution network, As shown in Fig. 2, single phase intermittent arc-earth faults occur for the branched line of Article 4 outlet, when faulted phase voltage reaches peak value Start arcing, extinguishes at random in power current zero passage, restrike at phase voltage peak value again by one or several periods.Electricity Arc voltage and current simulations waveform are as shown in Figure 3.Arcing time is respectively 0.098s, 0.138s, 0,218s, blow-out time difference For 0.128s, 0.183s.When in arc extinction, that is, 0.19s~0.21s in inject disturbing signal when, there are two types of may situation, First is that electric arc is not restriked during Injection Signal, as shown in Fig. 4 (a) figure, faulted phase current does not have faulted phase current waveform at this time Variation, fault location failure;Second is that the raising of faulted phase voltage makes electric arc restrike in advance (when 0.197s again during Injection Signal Combustion), at this time shown in faulted phase current waveform such as Fig. 4 (b), faulted phase current appearance increases in short-term, meet fault location requirement, but At this time electric arc restrike can heavy system overvoltage burden, intermittency electric arc's earthing over-voltage reach as high as phase voltage amplitude 2.2~ 2.5 times, it is unfavorable for system safety.If capturing the arc reignition moment and injecting disturbing signal (0.22s~0.25s) at once, this When faulted phase current waveform as shown in figure 5, faulted phase current significantly increases within disturbing signal injection period, it is fixed to meet failure Position requires, and period does not have arc reignition, will not heavy system overvoltage.

The present invention connects according to the electrical power distribution network fault location method based on parallel resistance disturbing signal in single phase intermittent electric arc Positional uncertainty problem in earth fault, proposes a kind of improved method, i.e., detects to arc burning state, captures electricity Arc is restriked the moment and injects disturbing signal at arc reignition initial stage at once.This method has as follows compared with injection disturbing signal at random Advantage:

1) ineffectivity for injecting disturbing signal during arc extinction is avoided, while being injected during avoiding arc extinction Disturbing signal causes faulted phase voltage raising to cause arc reignition, will not additional heavy system overvoltage burden.

2) disturbing signal is injected during arc burning, the increase of fault current is conducive to promote intermittent electric arc to stabilization Electric arc conversion reduces the harm of intermittent electric arc while improving the validity of fault location.

Obviously, above-described embodiment is only intended to clearly illustrate example, and does not limit the embodiments.For For those of ordinary skill in the art, other various forms of variations or change can also be made on the basis of the above description It is dynamic.There is no necessity and possibility to exhaust all the enbodiments.And obvious variation extended from this or change It moves still within the protection scope of the invention.

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