CN109298287A - Small current neutral grounding Distribution Network Failure kind identification method based on fault detector data - Google Patents

Small current neutral grounding Distribution Network Failure kind identification method based on fault detector data Download PDF

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Publication number
CN109298287A
CN109298287A CN201811417589.XA CN201811417589A CN109298287A CN 109298287 A CN109298287 A CN 109298287A CN 201811417589 A CN201811417589 A CN 201811417589A CN 109298287 A CN109298287 A CN 109298287A
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China
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fault
phase
fault detector
current
data
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CN201811417589.XA
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CN109298287B (en
Inventor
张林利
邵志敏
孙勇
李立生
张世栋
苏建军
任杰
文艳
孟海磊
房牧
李建修
刘合金
樊迪
王鑫
刘洋
王峰
苏国强
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State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Shandong Electric Power Co Ltd
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State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Shandong Electric Power Co Ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/081Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/086Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Locating Faults (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a kind of small current neutral grounding Distribution Network Failure kind identification method based on fault detector data, fault detector is installed on transmission line of electricity, acquisition unit is provided on fault detector, the three-phase current data that acquisition unit will acquire, which are delivered to, collects unit, collect unit for three-phase current tidal data recovering and form three-phase current data set and be sent to recognition unit, recognition unit is identified using following steps: (1) identifying singlephase earth fault and short trouble;(2) symmetrical short-circuit and Nonsymmetric Short Circuit are identified;(3) line to line fault and two-phase grounding fault are identified.The present invention utilizes A/D saturation characteristics and residual voltage feature of fault detector current data etc., simple and effective, practical, convenient for applying in existing distribution automation system.

Description

Small current neutral grounding Distribution Network Failure kind identification method based on fault detector data
Technical field
The present invention relates to a kind of small current neutral grounding Distribution Network Failure kind identification method based on fault detector data, belongs to Fault Diagnosis of Distribution Network technical field.
Background technique
Recording type fault detector is widely used in recent years, has recorded the fault recorder data of magnanimity, in power distribution automation system In system, the recorder data uploaded by fault detector judges fault type and is counted, and can effectively record failure hair Raw situation grasps failure distribution and and guides service work.Since the anti-interference of electric-field sensor is poor, original phase-selecting method holds Easily judge by accident, how combination failure indicator data feature, develop small current neutral grounding system Distribution Network Failure kind identification method, The problem of being urgent need to resolve in electric system.
In previous distribution network failure sort research, be all made of current transformer or voltage transformer acquisition electric current or Voltage signal extracts fault feature vector by different methods, and input classifier obtains fault type.The failure modes of acquisition The fault component of three-phase current after specifically including that failure with initial signal after 2ms zero-sequence current, residual voltage amount and failure, Transient current energy, stable state three-phase after faulted phase voltage, the phase information of stable fault currents, failure occur in 1/4 cycle Amplitude and phase of the order components of electric current etc..Feature extracting method mainly has: wavelet transformation, EMD (empirical mode decomposition), small echo Packet, approximate entropy etc..The classifier of use mainly includes Adaptive Fuzzy Neural-network, SVM (support vector machines), artificial immunity calculation Method etc..The recorder data of fault detector is presented new feature, the fault detector current measuring range of part of type compared with It is small, when short trouble occurs, because short circuit current is more than measuring range, it may appear that A/D saturated phenomenon.Simultaneously as voltage is logical The mode for crossing measurement electric field obtains, and causes voltage measuring value reliability low compared with current measurement value.
Summary of the invention
The present invention is to solve the above problems, provide a kind of small current neutral grounding Distribution Network Failure class based on fault detector data Type recognition methods, this method extract the fault detector recorder data feature under different faults, and using the feature of extraction as foundation Carry out fault type recognition.
To achieve the above object, for small current neutral grounding distribution, meter and short current range fault detector data characteristics, originally The small current neutral grounding Distribution Network Failure kind identification method based on fault detector data of invention is installed on transmission line of electricity faulty Indicator, which is characterized in that acquisition unit is provided on fault detector, the three-phase current data conveying that acquisition unit will acquire To unit is collected, collect unit for three-phase current tidal data recovering and form three-phase current data set and be sent to recognition unit, identifies Unit is identified using following steps:
(1) singlephase earth fault and short trouble are identified
When singlephase earth fault occurs, faulted phase voltage is reduced, and perfects phase voltage raising, and residual voltage increases, each outlet Zero-sequence current increases.Failure phase earth current is the sum of each sound circuit capacitance current, is usually no more than 100A, is far from reaching Fault detector current range maximum value, therefore be not in A/D saturated phenomenon.And short trouble, either three-phase shortcircuit, two Mutually short circuit or two-phase grounding fault, because short circuit current is larger, therefore the electric current A/D saturation that will appear a phase, two-phase or three-phase is existing As when, therefore propose the identical criterion of singlephase earth fault and short trouble: when fault detector recording three-phase current data, appointing When A/D saturated phenomenon occurs in the electric current of one phase, two-phase or three-phase, then determine that the failure is otherwise single-phase earthing for short trouble Failure.
The A/D saturated phenomenon are as follows: when current sampling data absolute value is range maximum value in continuous 1/20 period, Then think that A/D saturated phenomenon occurs.
(2) symmetrical short-circuit and Nonsymmetric Short Circuit are identified
There is no negative phase-sequence and zero-sequence components in route when generation three phase short circuit fault, and three-phase current amplitude is identical, three-phase electricity The phase difference of stream is still 120 °.Three phase short circuit fault is unique symmetrical fault and three-phase is short in studied fault type Road failure is also type more serious in short trouble, and the amplitude that short circuit current when such failure occurs is larger, therefore by failure The collected three-phase current of oscillograph acquisition unit should be at overcurrent or AD saturation state and saturation accounting at this time It is larger.Therefore the identical criterion of symmetrical short-circuit and Nonsymmetric Short Circuit is proposed: the fault detector record to having determined that as short trouble Wave number evidence determines that the secondary failure is symmetrical short if A/D saturated phenomenon occurs in the three-phase current in fault recorder data Road is determined as three phase short circuit fault.
(3) line to line fault and two-phase grounding fault are identified
When same outlet two-phase short circuit and ground fault occurs, if grounding point is identical, it is full that A/D occurs in failure biphase current And phenomenon, compared with line to line fault, residual voltage is significantly raised, it can generally reach 15% phase voltage, if grounding point is different, or When different outlet two-phases are grounded simultaneously, fault detector current data will appear a phase current A/D saturated phenomenon, therefore propose Line to line fault and two-phase short circuit and ground fault identical criterion: after having been identified as Nonsymmetric Short Circuit failure, if there is a phase current When A/D saturated phenomenon or residual voltage reach 15% phase voltage or more, then determine that the secondary failure is two-phase grounding fault, It otherwise is line to line fault.
The present invention is directed to small current neutral grounding distribution, meter and short current range fault detector data characteristics, proposes a kind of base In the small current neutral grounding Distribution Network Failure kind identification method of fault detector data.This method is merely with fault detector electric current number According to A/D saturation characteristics and residual voltage feature etc., it is simple and effective, it is practical, convenient in existing distribution automation system Using.The present invention provides a kind of feasible method for the identification of distribution line failure type, is conducive to grasp Distribution Network Failure The regularity of distribution pointedly formulates Control of Hidden and failure prevention measure, promotes distribution network failure management level.
Detailed description of the invention
Fig. 1 is distribution line fault detector configuration schematic diagram;
Fig. 2 is the flow chart of the Distribution Network Failure kind identification method the present invention is based on fault detector data;
The recorder data of one fault detector when Fig. 3 is singlephase earth fault;
The recorder data of one fault detector when Fig. 4 is three phase short circuit fault;
The recorder data of one fault detector when Fig. 5 is two-phase short-circuit fault;
The recorder data of one fault detector when Fig. 6 is two-phase short circuit and ground fault.
Specific embodiment
The present invention is directed to small current neutral grounding distribution, meter and short current range fault detector data characteristics, proposes a kind of base In the small current neutral grounding Distribution Network Failure kind identification method of fault detector data, ground fault, three-phase shortcircuit, two-phase are analyzed The fault detector Wave data feature of short circuit and two-phase grounding fault, it is full merely with the A/D of fault detector current data With feature and residual voltage feature etc., fault type recognition method is proposed, successively identifies single-phase earthing and short circuit, symmetrical short-circuit With Nonsymmetric Short Circuit, line to line fault and two-phase grounding fault.
Distribution Network Failure kind identification method based on fault detector data of the invention, as shown in Figure 1, on transmission line of electricity Fault detector is installed, acquisition unit is provided on fault detector, the three-phase current data conveying that acquisition unit will acquire To unit is collected, collect unit for three-phase current tidal data recovering and form three-phase current data set and be sent to recognition unit, identifies Unit identified using following steps, specifically include the following three steps:
One, identifies singlephase earth fault and short trouble: as fault detector three-phase recording current data, Ren Yixiang, two When mutually or the electric current of three-phase A/D saturated phenomenon occurs, then determine that the failure is otherwise singlephase earth fault for short trouble;Institute State A/D saturated phenomenon are as follows: when current sampling data absolute value is range maximum value in continuous 1/20 period, then it is assumed that occur A/D saturated phenomenon;By taking Fig. 3 as an example, it is existing that the fault detector current measurement data of same substation's outlet does not occur A/D saturation As, therefore finally judge the failure for singlephase earth fault.
Two, identify symmetrical short-circuit and Nonsymmetric Short Circuit: to the fault detector recorder data having determined that as short trouble, such as There is A/D saturated phenomenon in three-phase current in fruit fault recorder data, then determines that the secondary failure is symmetrical short-circuit, that is, be determined as Three phase short circuit fault;By taking Fig. 4 as an example, there is AD saturated phenomenon in fault detector three-phase current data, therefore final judgement should Failure is three phase short circuit fault.
Three, identify line to line fault and two-phase grounding fault: after having been identified as Nonsymmetric Short Circuit failure, if there is phase electricity When stream A/D saturated phenomenon or residual voltage reach 15% phase voltage or more, then determine that the secondary failure is short for two phase ground Otherwise road is line to line fault;By taking Fig. 5 as an example, there is A/D saturated phenomenon, and residual voltage in fault detector current data two-phase Less than 15% phase voltage, therefore it is judged as two-phase short-circuit fault;By taking Fig. 6 as an example, there is A/D in fault detector current data two-phase Saturated phenomenon, and residual voltage is greater than 15% phase voltage, therefore is judged as two-phase short circuit and ground fault.
Although above-mentioned be described and verify to a specific embodiment of the invention and validity in conjunction with attached drawing, not Limiting the scope of the invention, those skilled in the art should understand that, based on the technical solutions of the present invention, this Field technical staff does not need to make the creative labor the various modifications or changes that can be made still in protection scope of the present invention Within.

Claims (4)

1. a kind of small current neutral grounding Distribution Network Failure kind identification method based on fault detector data, it is equipped on transmission line of electricity Fault detector, characterized in that acquisition unit is provided on fault detector, the three-phase current data that acquisition unit will acquire are defeated It send to unit is collected, collect unit for three-phase current tidal data recovering and forms three-phase current data set and be sent to recognition unit, know Other unit is identified using following steps:
(1) singlephase earth fault and short trouble are identified: when fault detector recording three-phase current data, Ren Yixiang, two-phase or When A/D saturated phenomenon occurs in the electric current of three-phase, then determine that the failure is otherwise singlephase earth fault for short trouble;
(2) symmetrical short-circuit and Nonsymmetric Short Circuit are identified: to the fault detector recorder data having determined that as short trouble, if therefore There is A/D saturated phenomenon in three-phase current in barrier recorder data, then determines that the secondary failure is symmetrical short-circuit, that is, be determined as three-phase Short trouble;
(3) line to line fault and two-phase grounding fault are identified: after having been identified as Nonsymmetric Short Circuit failure, if there is a phase current A/ When D saturated phenomenon or residual voltage reach 15% phase voltage or more, then determine that the secondary failure is two-phase grounding fault, it is no It is then line to line fault;
2. the small current neutral grounding Distribution Network Failure kind identification method based on fault detector data as described in claim 1, special Sign is A/D saturated phenomenon are as follows: when current sampling data absolute value is range maximum value in continuous 1/20 period, then it is assumed that A/D saturated phenomenon occurs;
3. the small current neutral grounding Distribution Network Failure kind identification method based on fault detector data as described in claim 1, special Sign is that fault detector is that the maximum value of current measurement range is greater than load current but is less than the fault detector of short circuit current.
4. the small current neutral grounding Distribution Network Failure kind identification method based on fault detector data as described in claim 1, special Sign is that the current measurement range of the fault detector is 0-600A.
CN201811417589.XA 2018-11-26 2018-11-26 Fault indicator data-based method for identifying fault type of low-current grounding distribution network Active CN109298287B (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110112712A (en) * 2019-04-30 2019-08-09 广东电网有限责任公司 Power distribution network earth protective device and its sampling control method with the configuration of double mutual inductors
CN110231543A (en) * 2019-06-26 2019-09-13 国网山东省电力公司临沂供电公司 Power distribution network abnormality recognition method
CN110579690A (en) * 2019-10-29 2019-12-17 厦门理工学院 Positioning method for small current ground fault section of power distribution network
CN110687400A (en) * 2019-10-16 2020-01-14 东方电子股份有限公司 Method for filtering false start of transient recording type fault indicator
CN110879371A (en) * 2019-11-28 2020-03-13 赫兹曼电力(广东)有限公司 Overhead line small current grounding detection box and fault detection method thereof
CN111551824A (en) * 2020-05-15 2020-08-18 中国南方电网有限责任公司 Phase voltage amplitude and phase angle change rate ground fault phase selection method and device considering three-phase asymmetry
CN111598166A (en) * 2020-05-18 2020-08-28 国网山东省电力公司电力科学研究院 Single-phase earth fault classification method and system based on principal component analysis and Softmax function
CN112782528A (en) * 2020-12-31 2021-05-11 西安理工大学 Power distribution network fault section positioning method using PMU
CN112881942A (en) * 2021-01-14 2021-06-01 应急管理部四川消防研究所 Abnormal current diagnosis method and system based on wavelet decomposition and empirical mode decomposition
CN113092936A (en) * 2021-04-02 2021-07-09 中国矿业大学 Power distribution network cable fault section identification method based on multi-source data cooperation
CN113109733A (en) * 2021-03-23 2021-07-13 兰州资源环境职业技术学院 Overhead cable short circuit grounding fault detection system based on wireless sensor network

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3458123B2 (en) * 1998-05-01 2003-10-20 中部電力株式会社 Ground fault point display
CN101738565A (en) * 2010-01-14 2010-06-16 北京双杰电气股份有限公司 Adaptive fault indicator
CN203149069U (en) * 2013-03-20 2013-08-21 国家电网公司 Fault classification display fault indicator
CN108132425A (en) * 2017-12-18 2018-06-08 云南电网有限责任公司电力科学研究院 Power grid distribution line failure on-line monitoring method and system
CN207924054U (en) * 2018-01-29 2018-09-28 宁波三星智能电气有限公司 A kind of fault detector
CN108710064A (en) * 2018-07-27 2018-10-26 四川瑞霆电力科技有限公司 A kind of zero sequence active component molded line line fault indicator

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3458123B2 (en) * 1998-05-01 2003-10-20 中部電力株式会社 Ground fault point display
CN101738565A (en) * 2010-01-14 2010-06-16 北京双杰电气股份有限公司 Adaptive fault indicator
CN203149069U (en) * 2013-03-20 2013-08-21 国家电网公司 Fault classification display fault indicator
CN108132425A (en) * 2017-12-18 2018-06-08 云南电网有限责任公司电力科学研究院 Power grid distribution line failure on-line monitoring method and system
CN207924054U (en) * 2018-01-29 2018-09-28 宁波三星智能电气有限公司 A kind of fault detector
CN108710064A (en) * 2018-07-27 2018-10-26 四川瑞霆电力科技有限公司 A kind of zero sequence active component molded line line fault indicator

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
张志霞: "《小电流接地系统单相接地故障选线理论研究》", 30 April 2014, 辽宁科学技术出版社 *
杨帆 等: "小电流接地故障多层次分类及其识别模型", 《电力系统自动化》 *
薛永端 等: "小电流接地故障暂态分析及区段定位新方法", 《电力系统自动化》 *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110112712A (en) * 2019-04-30 2019-08-09 广东电网有限责任公司 Power distribution network earth protective device and its sampling control method with the configuration of double mutual inductors
CN110112712B (en) * 2019-04-30 2021-08-03 广东电网有限责任公司 Power distribution network grounding protection device with double-transformer configuration and sampling control method thereof
CN110231543A (en) * 2019-06-26 2019-09-13 国网山东省电力公司临沂供电公司 Power distribution network abnormality recognition method
CN110687400B (en) * 2019-10-16 2021-07-20 东方电子股份有限公司 Method for filtering false start of transient recording type fault indicator
CN110687400A (en) * 2019-10-16 2020-01-14 东方电子股份有限公司 Method for filtering false start of transient recording type fault indicator
CN110579690A (en) * 2019-10-29 2019-12-17 厦门理工学院 Positioning method for small current ground fault section of power distribution network
CN110579690B (en) * 2019-10-29 2021-11-23 厦门理工学院 Positioning method for small current ground fault section of power distribution network
CN110879371A (en) * 2019-11-28 2020-03-13 赫兹曼电力(广东)有限公司 Overhead line small current grounding detection box and fault detection method thereof
CN111551824A (en) * 2020-05-15 2020-08-18 中国南方电网有限责任公司 Phase voltage amplitude and phase angle change rate ground fault phase selection method and device considering three-phase asymmetry
CN111598166A (en) * 2020-05-18 2020-08-28 国网山东省电力公司电力科学研究院 Single-phase earth fault classification method and system based on principal component analysis and Softmax function
CN111598166B (en) * 2020-05-18 2023-10-17 国网山东省电力公司电力科学研究院 Single-phase earth fault classification method and system based on principal component analysis and Softmax function
CN112782528A (en) * 2020-12-31 2021-05-11 西安理工大学 Power distribution network fault section positioning method using PMU
CN112881942A (en) * 2021-01-14 2021-06-01 应急管理部四川消防研究所 Abnormal current diagnosis method and system based on wavelet decomposition and empirical mode decomposition
CN112881942B (en) * 2021-01-14 2023-04-07 应急管理部四川消防研究所 Abnormal current diagnosis method and system based on wavelet decomposition and empirical mode decomposition
CN113109733A (en) * 2021-03-23 2021-07-13 兰州资源环境职业技术学院 Overhead cable short circuit grounding fault detection system based on wireless sensor network
CN113109733B (en) * 2021-03-23 2023-12-15 兰州资源环境职业技术学院 Overhead cable short-circuit ground fault detection system based on wireless sensor network
CN113092936A (en) * 2021-04-02 2021-07-09 中国矿业大学 Power distribution network cable fault section identification method based on multi-source data cooperation

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