CN110514955A - A kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization method - Google Patents
A kind of low current neutral grounding electric network single phase intermittent arc-earth faults localization method Download PDFInfo
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- CN110514955A CN110514955A CN201910585056.0A CN201910585056A CN110514955A CN 110514955 A CN110514955 A CN 110514955A CN 201910585056 A CN201910585056 A CN 201910585056A CN 110514955 A CN110514955 A CN 110514955A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
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.
Description
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.
Claims (7)
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.
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Cited By (3)
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| CN113567810A (en) * | 2021-07-30 | 2021-10-29 | 中国矿业大学 | Method, device and system for positioning arc grounding fault section of power distribution network |
| CN112068028B (en) * | 2020-09-09 | 2022-06-14 | 南方电网科学研究院有限责任公司 | Intermittent single-phase earth fault identification method |
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