CN111007359A - Power distribution network single-phase earth fault identification starting method and system - Google Patents
Power distribution network single-phase earth fault identification starting method and system Download PDFInfo
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- CN111007359A CN111007359A CN201911366739.3A CN201911366739A CN111007359A CN 111007359 A CN111007359 A CN 111007359A CN 201911366739 A CN201911366739 A CN 201911366739A CN 111007359 A CN111007359 A CN 111007359A
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- 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
Abstract
The invention provides a method and a system for identifying and starting a single-phase earth fault of a power distribution network, wherein the invention adopts sudden change of a zero sequence voltage sampling value as a single-phase earth fault starting criterion, and compared with the traditional method, when a high-resistance earth fault occurs, the effective value of zero sequence voltage is very small, and the change quantity of the effective value of zero sequence voltage is also very small, so that the single-phase earth fault cannot be identified and removedt‑x’t|>2U and xt>When the voltage is 2U, the sampling value is counted as a sudden change of the zero sequence voltage sampling value, and the method has the advantage of high sensitivity; when the zero sequence voltage sampling value mutation continuously occurs three times, the single-phase fault grounding judgment is started, and the three-time mutation is usedThe method can effectively filter accidental sudden change caused by interference of the zero sequence voltage, and has the advantages of stability and reliability.
Description
Technical Field
The invention relates to the technical field of power distribution network fault identification, in particular to a power distribution network single-phase earth fault identification starting method and system.
Background
China mostly adopts a neutral point ungrounded mode and a neutral point resonance grounding mode, during operation, single-phase grounding faults account for about 80% of total faults, and loss can be timely recovered by quickly identifying and removing the single-phase grounding faults, so that huge economic and social benefits are generated.
When a single-phase earth fault is identified, the traditional method adopts the change quantity of the zero-sequence voltage exceeding a set threshold value or the effective value of the zero-sequence voltage as a judgment condition. When a high-resistance earth fault occurs, the effective value of the zero-sequence voltage is very small, and the change quantity of the effective value of the zero-sequence voltage is also very small, so that the single-phase earth fault cannot be identified and removed.
Disclosure of Invention
The invention aims to provide a power distribution network single-phase earth fault identification starting method and system, and aims to solve the problem that faults cannot be identified by adopting effective value variable quantity as fault judgment basis in the prior art, realize that sampling values are used as earth judgment starting conditions, and improve sensitivity and reliability.
In order to achieve the technical purpose, the invention provides a single-phase earth fault identification starting method for a power distribution network, which comprises the following steps:
s1, sampling the zero sequence voltage in real time, and calculating the zero sequence voltage effective value U every other cycle;
s2, comparing the sampling values of adjacent cycle sampling points, if | x existst-x’t|>2U and xt>When the voltage is 2U, the sampling value of the zero sequence voltage is counted to be suddenly changed;
and S3, when the mutation times of the zero-sequence sampling value exceed a threshold value, taking transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point, and performing single-phase fault grounding positioning judgment by using a zero-sequence power direction method.
Preferably, the calculation of the zero sequence voltage effective value U is obtained by fourier transform.
Preferably, the single-phase fault ground positioning and judging by using the zero-sequence power direction method specifically operates as follows:
calculating the angle relation between the zero sequence voltage and the zero sequence current by using transient state sampling data of each cycle of the zero sequence voltage and the zero sequence current, assuming that the angle of zero sequence current lagging the zero sequence voltage is theta, and judging as a ground fault when the theta is more than or equal to 80 degrees and less than or equal to 265 degrees; otherwise, when the theta is more than or equal to 265 degrees and less than or equal to 360 degrees or the theta is more than or equal to 0 degrees and less than or equal to 80 degrees, the fault is judged to be a non-grounding fault.
The invention also provides a power distribution network single-phase earth fault identification starting system, which comprises:
the zero sequence voltage effective value acquisition module is used for sampling the zero sequence voltage in real time and calculating a zero sequence voltage effective value U every other cycle;
the zero sequence voltage sampling value mutation acquisition module is used for comparing sampling values of adjacent cycle sampling points, and when | x |, existst-x’t|>2U and xt>When the voltage is 2U, the sampling value of the zero sequence voltage is counted to be suddenly changed;
and the single-phase fault grounding judgment module is used for taking transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point when the mutation times of the zero-sequence sampling value exceeds a threshold value, and performing single-phase fault grounding positioning judgment by using a zero-sequence power direction method.
Preferably, the calculation of the zero sequence voltage effective value U is obtained by fourier transform.
Preferably, the single fault ground determining module includes:
the transient data acquisition unit is used for acquiring transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point when the mutation frequency of the zero-sequence sampling value exceeds a threshold value;
the single-phase fault grounding positioning unit is used for calculating the angle relation between the zero sequence voltage and the zero sequence current by using transient state sampling data of each cycle of the zero sequence voltage and the zero sequence current, supposing that the zero sequence current lags the zero sequence voltage by an angle theta, and judging as a grounding fault when the theta is more than or equal to 80 degrees and less than or equal to 265 degrees; otherwise, when the theta is more than or equal to 265 degrees and less than or equal to 360 degrees or the theta is more than or equal to 0 degrees and less than or equal to 80 degrees, the fault is judged to be a non-grounding fault.
The effect provided in the summary of the invention is only the effect of the embodiment, not all the effects of the invention, and one of the above technical solutions has the following advantages or beneficial effects:
compared with the prior art, the single-phase earth fault starting criterion is the sudden change of the sampling value of the zero-sequence voltage, compared with the traditional method that when the high-resistance earth fault occurs, the effective value of the zero-sequence voltage is very small, the change quantity of the effective value of the zero-sequence voltage is also very small, and the single-phase earth fault cannot be identified and removedt-x’t|>2U and xt>When the voltage is 2U, the sampling value is counted as a sudden change of the zero sequence voltage sampling value, and the method has the advantage of high sensitivity; when the zero sequence voltage sampling value is suddenly changed three times continuously, the single-phase fault grounding judgment is started, and the accidental sudden change condition caused by the interference of the zero sequence voltage can be effectively filtered by the three sudden changes, so that the method has the advantages of stability and reliability.
Drawings
Fig. 1 is a logic flow diagram of a power distribution network single-phase ground fault identification starting method provided in an embodiment of the present invention;
fig. 2 is a schematic diagram of a zero-sequence voltage waveform provided in the embodiment of the present invention.
Detailed Description
In order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.
The method and the system for identifying and starting the single-phase earth fault of the power distribution network provided by the embodiment of the invention are described in detail below with reference to the accompanying drawings.
As shown in fig. 1, an embodiment of the present invention discloses a method for identifying and starting a single-phase earth fault of a power distribution network, where the method includes the following steps:
s1, sampling the zero sequence voltage in real time, and calculating the zero sequence voltage effective value U every other cycle;
s2, comparing the sampling values of adjacent cycle sampling points, if | x existst-x’t|>2U and xt>When the voltage is 2U, the sampling value of the zero sequence voltage is counted to be suddenly changed;
and S3, when the mutation times of the zero-sequence sampling value exceed a threshold value, taking transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point, and performing single-phase fault grounding positioning judgment by using a zero-sequence power direction method.
The embodiment of the invention utilizes the abrupt change of the sampling value of the zero sequence voltage as the starting judgment basis of the single-phase earth fault, when the variation of the sampling value exceeds the set threshold value, the abrupt change of the sampling value is judged, and the single-phase earth fault judgment is started.
And (3) sampling the zero sequence voltage in real time, wherein the sampling frequency is f, and calculating the zero sequence voltage effective value U by utilizing Fourier transform every 20ms (one cycle). As shown in FIG. 2, the one cycle time is 20ms, e.g., sample point x't-1And xt-1Is 20 ms.
Comparing the sampling value x of the zero sequence voltage, wherein the current sampling value xtThe sampling value corresponding to the previous 20ms is x'tWhen the following are present:
|xt-x’t|>2U and xt>2U
Counting the sudden change of a zero sequence voltage sampling value;
when the zero sequence voltage sampling value is suddenly changed for three times continuously, starting single-phase fault grounding judgment;
and starting from the first catastrophe point, sampling data of half cycle wave before the first catastrophe point and sampling data of half cycle wave after the first catastrophe point are obtained, synchronously recording the sampling data of zero sequence current at the same moment, and performing single-phase fault grounding judgment by using the transient data and adopting a power direction method.
The specific operation of the power direction method for single-phase fault grounding judgment is as follows:
calculating the angle relation between the zero sequence voltage and the zero sequence current by using transient state sampling data of each cycle of the zero sequence voltage and the zero sequence current, assuming that the angle of zero sequence current lagging the zero sequence voltage is theta, and judging as a ground fault when the theta is more than or equal to 80 degrees and less than or equal to 265 degrees; otherwise, when the theta is more than or equal to 265 degrees and less than or equal to 360 degrees or the theta is more than or equal to 0 degrees and less than or equal to 80 degrees, the fault is judged to be a non-grounding fault.
The embodiment of the invention adopts the sudden change of the sampling value of the zero sequence voltage as the starting criterion of the single-phase earth fault, compared with the traditional method that when the high-resistance earth fault occurs, the effective value of the zero sequence voltage is very small, the change quantity of the effective value of the zero sequence voltage is also very small, so that the single-phase earth fault cannot be identified and removedt-x’t|>2U and xt>When the voltage is 2U, the sampling value is counted as a sudden change of the zero sequence voltage sampling value, and the method has the advantage of high sensitivity; when the zero sequence voltage sampling value is suddenly changed three times continuously, the single-phase fault grounding judgment is started, and the accidental sudden change condition caused by the interference of the zero sequence voltage can be effectively filtered by the three sudden changes, so that the method has the advantages of stability and reliability.
The embodiment of the invention also discloses a system for identifying and starting the single-phase earth fault of the power distribution network, which comprises the following steps:
the zero sequence voltage effective value acquisition module is used for sampling the zero sequence voltage in real time and calculating a zero sequence voltage effective value U every other cycle;
the zero sequence voltage sampling value mutation acquisition module is used for comparing sampling values of adjacent cycle sampling points, and when | x |, existst-x’t|>2U and xt>When the voltage is 2U, the sampling value of the zero sequence voltage is counted to be suddenly changed;
and the single-phase fault grounding judgment module is used for taking transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point when the mutation times of the zero-sequence sampling value exceeds a threshold value, and performing single-phase fault grounding positioning judgment by using a zero-sequence power direction method.
Sampling zero sequence voltage in real time, wherein the sampling frequency is f, and calculating a zero sequence voltage effective value U by utilizing Fourier transform every 20ms (one cycle); comparing the sampling value x of the zero sequence voltage, wherein the current sampling value xtThe sampling value corresponding to the previous 20ms is x'tWhen the following are present:
|xt-x’t|>2U and xt>2U
Counting the sudden change of a zero sequence voltage sampling value;
when the zero sequence voltage sampling value is suddenly changed for three times continuously, starting single-phase fault grounding judgment;
and starting from the first catastrophe point, sampling data of half cycle wave before the first catastrophe point and sampling data of half cycle wave after the first catastrophe point are obtained, synchronously recording the sampling data of zero sequence current at the same moment, and performing single-phase fault grounding judgment by using the transient data and adopting a power direction method.
The single fault grounding judgment module comprises:
the transient data acquisition unit is used for acquiring transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point when the mutation frequency of the zero-sequence sampling value exceeds a threshold value;
the single-phase fault grounding positioning unit is used for calculating the angle relation between the zero sequence voltage and the zero sequence current by using transient state sampling data of each cycle of the zero sequence voltage and the zero sequence current, supposing that the zero sequence current lags the zero sequence voltage by an angle theta, and judging as a grounding fault when the theta is more than or equal to 80 degrees and less than or equal to 265 degrees; otherwise, when the theta is more than or equal to 265 degrees and less than or equal to 360 degrees or the theta is more than or equal to 0 degrees and less than or equal to 80 degrees, the fault is judged to be a non-grounding fault.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (6)
1. A single-phase earth fault identification starting method for a power distribution network is characterized by comprising the following steps:
s1, sampling the zero sequence voltage in real time, and calculating the zero sequence voltage effective value U every other cycle;
s2, comparing the sampling values of adjacent cycle sampling points, if | x existst-x’t|>2U and xt>When the voltage is 2U, the sampling value of the zero sequence voltage is counted to be suddenly changed;
and S3, when the mutation times of the zero-sequence sampling value exceed a threshold value, taking transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point, and performing single-phase fault grounding positioning judgment by using a zero-sequence power direction method.
2. The single-phase earth fault identification starting method for the power distribution network according to claim 1, wherein the calculation of the zero sequence voltage effective value U is obtained by fourier transform.
3. The method for identifying and starting the single-phase earth fault of the power distribution network according to claim 1, wherein the single-phase earth fault positioning and judging by using the zero-sequence power direction method specifically comprises the following operations:
calculating the angle relation between the zero sequence voltage and the zero sequence current by using transient state sampling data of each cycle of the zero sequence voltage and the zero sequence current, assuming that the angle of zero sequence current lagging the zero sequence voltage is theta, and judging as a ground fault when the theta is more than or equal to 80 degrees and less than or equal to 265 degrees; otherwise, when the theta is more than or equal to 265 degrees and less than or equal to 360 degrees or the theta is more than or equal to 0 degrees and less than or equal to 80 degrees, the fault is judged to be a non-grounding fault.
4. A power distribution network single-phase ground fault identification start-up system, the system comprising:
the zero sequence voltage effective value acquisition module is used for sampling the zero sequence voltage in real time and calculating a zero sequence voltage effective value U every other cycle;
the zero sequence voltage sampling value mutation acquisition module is used for comparing sampling values of adjacent cycle sampling points, and when | x |, existst-x’t|>2U and xt>When the voltage is 2U, the sampling value of the zero sequence voltage is counted to be suddenly changed;
and the single-phase fault grounding judgment module is used for taking transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point when the mutation times of the zero-sequence sampling value exceeds a threshold value, and performing single-phase fault grounding positioning judgment by using a zero-sequence power direction method.
5. The power distribution network single-phase earth fault identification starting system according to claim 4, wherein the calculation of the zero sequence voltage effective value U is obtained by Fourier transform.
6. The power distribution network single-phase earth fault identification starting system according to claim 4, wherein the single-phase earth fault judgment module comprises:
the transient data acquisition unit is used for acquiring transient data of zero-sequence voltage and zero-sequence current of half cycle before and after the first mutation point when the mutation frequency of the zero-sequence sampling value exceeds a threshold value;
the single-phase fault grounding positioning unit is used for calculating the angle relation between the zero sequence voltage and the zero sequence current by using transient state sampling data of each cycle of the zero sequence voltage and the zero sequence current, supposing that the zero sequence current lags the zero sequence voltage by an angle theta, and judging as a grounding fault when the theta is more than or equal to 80 degrees and less than or equal to 265 degrees; otherwise, when the theta is more than or equal to 265 degrees and less than or equal to 360 degrees or the theta is more than or equal to 0 degrees and less than or equal to 80 degrees, the fault is judged to be a non-grounding fault.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111796203A (en) * | 2020-06-03 | 2020-10-20 | 深圳蓄能发电有限公司 | Identification method and device for single-phase earth fault at network bridge side of static frequency converter |
| CN111856205A (en) * | 2020-06-19 | 2020-10-30 | 南方电网科学研究院有限责任公司 | Power distribution network fault indication system and method |
| CN112083276A (en) * | 2020-08-21 | 2020-12-15 | 广东电网有限责任公司广州供电局 | Method and system for identifying arc grounding fault |
| CN114089093A (en) * | 2021-10-13 | 2022-02-25 | 国电南瑞科技股份有限公司 | Single-phase earth fault starting judging method, system, storage medium and computing equipment |
| CN115356658A (en) * | 2022-10-21 | 2022-11-18 | 国网信息通信产业集团有限公司 | Power distribution network single-phase earth fault starting detection method and system |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102608500A (en) * | 2012-04-03 | 2012-07-25 | 云南电网公司玉溪供电局 | High-resistance, single-phase ground fault line selection device for distribution networks and starting method thereof |
| CN102955098A (en) * | 2012-12-10 | 2013-03-06 | 四川省电力公司资阳公司 | Neutral point non-effective earthing system single-phase earthing fault identification method |
| CN104049140A (en) * | 2014-06-28 | 2014-09-17 | 国家电网公司 | Zero-sequence fault current sudden-change used small-current grounding fault starting method |
| CN107422223A (en) * | 2016-12-28 | 2017-12-01 | 国网福建省电力有限公司 | A kind of method of distributed low current grounding positioning |
| CN108695864A (en) * | 2018-06-06 | 2018-10-23 | 国网上海市电力公司 | Power distribution network network topology analytical method based on μ PMU and SCADA |
| CN109307824A (en) * | 2018-09-18 | 2019-02-05 | 福州大学 | A kind of one-phase earthing failure in electric distribution network Section Location based on cluster |
| CN109696598A (en) * | 2018-12-26 | 2019-04-30 | 四川大学 | A kind of distribution network fault line selection method considering subsequent fault |
| CN110389281A (en) * | 2018-04-23 | 2019-10-29 | 西门子股份公司 | The method and apparatus of power line where determining power grid intermittent ground fault |
| CN110441641A (en) * | 2019-07-24 | 2019-11-12 | 南京国电南自电网自动化有限公司 | A kind of small current earthing wire-selecting method and system based on Zero sequence DC component |
-
2019
- 2019-12-26 CN CN201911366739.3A patent/CN111007359A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102608500A (en) * | 2012-04-03 | 2012-07-25 | 云南电网公司玉溪供电局 | High-resistance, single-phase ground fault line selection device for distribution networks and starting method thereof |
| CN102955098A (en) * | 2012-12-10 | 2013-03-06 | 四川省电力公司资阳公司 | Neutral point non-effective earthing system single-phase earthing fault identification method |
| CN104049140A (en) * | 2014-06-28 | 2014-09-17 | 国家电网公司 | Zero-sequence fault current sudden-change used small-current grounding fault starting method |
| CN107422223A (en) * | 2016-12-28 | 2017-12-01 | 国网福建省电力有限公司 | A kind of method of distributed low current grounding positioning |
| CN110389281A (en) * | 2018-04-23 | 2019-10-29 | 西门子股份公司 | The method and apparatus of power line where determining power grid intermittent ground fault |
| CN108695864A (en) * | 2018-06-06 | 2018-10-23 | 国网上海市电力公司 | Power distribution network network topology analytical method based on μ PMU and SCADA |
| CN109307824A (en) * | 2018-09-18 | 2019-02-05 | 福州大学 | A kind of one-phase earthing failure in electric distribution network Section Location based on cluster |
| CN109696598A (en) * | 2018-12-26 | 2019-04-30 | 四川大学 | A kind of distribution network fault line selection method considering subsequent fault |
| CN110441641A (en) * | 2019-07-24 | 2019-11-12 | 南京国电南自电网自动化有限公司 | A kind of small current earthing wire-selecting method and system based on Zero sequence DC component |
Non-Patent Citations (3)
| Title |
|---|
| 张利 等: "基于零序功率方向的中性点不接地系统在线故障定位", 《电力系统自动化》 * |
| 李晓波: "柔性零残流消弧线圈的研究", 《中国博士学位论文全文数据库 工程科技Ⅱ辑》 * |
| 李毅军: "对故障分量原理的微机型发变组差动保护装置在运行中一些问题的探讨", 《继电器》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111796203A (en) * | 2020-06-03 | 2020-10-20 | 深圳蓄能发电有限公司 | Identification method and device for single-phase earth fault at network bridge side of static frequency converter |
| CN111796203B (en) * | 2020-06-03 | 2022-08-26 | 深圳蓄能发电有限公司 | Identification method and device for single-phase earth fault at network bridge side of static frequency converter |
| CN111856205A (en) * | 2020-06-19 | 2020-10-30 | 南方电网科学研究院有限责任公司 | Power distribution network fault indication system and method |
| CN112083276A (en) * | 2020-08-21 | 2020-12-15 | 广东电网有限责任公司广州供电局 | Method and system for identifying arc grounding fault |
| CN114089093A (en) * | 2021-10-13 | 2022-02-25 | 国电南瑞科技股份有限公司 | Single-phase earth fault starting judging method, system, storage medium and computing equipment |
| CN115356658A (en) * | 2022-10-21 | 2022-11-18 | 国网信息通信产业集团有限公司 | Power distribution network single-phase earth fault starting detection method and system |
| CN115356658B (en) * | 2022-10-21 | 2023-03-07 | 国网信息通信产业集团有限公司 | Power distribution network single-phase earth fault starting detection method and system |
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