CN108287296B - High-resistance grounding fault reverse starting and line selection method suitable for asymmetric power grid - Google Patents
High-resistance grounding fault reverse starting and line selection method suitable for asymmetric power grid Download PDFInfo
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- CN108287296B CN108287296B CN201810125114.7A CN201810125114A CN108287296B CN 108287296 B CN108287296 B CN 108287296B CN 201810125114 A CN201810125114 A CN 201810125114A CN 108287296 B CN108287296 B CN 108287296B
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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
Abstract
A reverse starting processing and line selection method suitable for an asymmetric power grid high-resistance earth fault is used for detecting a neutral point displacement voltage U of a power distribution network in real time when the power distribution network operatesNAnd each feeder zero sequence current In0If in the time period
Neutral point voltage of internal and external distribution network
Stable change occurs, and the neutral point voltage of the power distribution network
Reaches a certain value, Δ UNMay be in a forward increment
May also be in reverse increments
But the amplitude of the variation is satisfied
In time, the zero sequence current increment in any feeder line in the power distribution network simultaneously satisfies
And is and
Description
Technical Field
The invention belongs to the field of single-phase earth fault processing of a power distribution network, and is mainly used for starting processing and earth line selection of an earth fault processing device when neutral point displacement voltage is reduced during high-resistance earth fault of an asymmetric power grid.
Background
Different single-phase earth fault processing devices have different fault starting modes and fault starting values, but most of the devices adopt the displacement voltage of the neutral point of the power grid as the fault starting value of the single-phase earth fault. However, the power grid has different parameters to the ground, the power grid has different asymmetry degrees, the displacement voltage of the neutral point of the power grid is also different, the neutral point is not grounded, and the value range of the asymmetry coefficient is 0-5%. The test finds that: when a high-resistance earth fault occurs to a certain phase of an asymmetric power grid, the neutral point shifts the voltage UNThe device cannot start to process the single-phase earth fault starting mode by using the displacement voltage of the neutral point of the power grid as a single-phase earth fault starting mode and the displacement voltage of the neutral point of the power grid as a fixed value or start to process the earth fault by using increment, because the phenomenon is that the earth fault processing device in the power grid cannot start to process the single-phase earth fault starting mode by using the displacement voltage of the neutral point of the power grid as a fixed valueThe reduction of the neutral point displacement voltage generally means that the power grid tends to develop towards the balance direction of a normal value, but the fact is that a single-phase high-resistance earth fault does occur, so a method must be found for solving the problems of neutral point displacement reverse starting processing and line selection when the asymmetric power grid high-resistance earth fault occurs.
Disclosure of Invention
In order to solve the problems of neutral point displacement reverse starting processing and line selection during the high-resistance earth fault of an asymmetric power grid, the invention provides the neutral point displacement reverse starting processing and line selection method suitable for the high-resistance earth fault of the asymmetric power grid, and the neutral point displacement voltage U of the power distribution network is detected in real time during the operation of the power distribution networkNAnd each feeder zero sequence current In0If the voltage U is displaced from the neutral point of the power distribution network within the time period delta TNStable change occurs, and the neutral point of the power distribution network shifts voltage UNReaches a value of atNIn reverse increments, i.e. Δ U<0, but the amplitude of the change is satisfied
While, UStarting voltage fixed value for neutral point displacement voltage fault, and simultaneously enabling zero sequence current increment in any feeder line in the power distribution network to meet delta I0≥I，IIs a zero-sequence current increment constant value, and the maximum zero-sequence current I in the feeder lineMAX0≥I0B，I0BIf the current value is the maximum zero sequence current value caused by the asymmetry of the power grid, judging that the power distribution network has single-phase high-resistance earth fault, and judging that the power distribution network has single-phase high-resistance earth fault, wherein the earth fault processing device enters fault starting to process the single-phase earth fault; at the moment, the feeder line with the largest zero sequence current increment in each line is the line generating single-phase grounding; delta T is the time period of the continuous increment of the power grid parameters; u shapeAnd starting voltage fixed value for neutral point displacement voltage fault.
Δ T should be greater than the duration of the grid disturbance.
UDifferent settings are made according to different ground fault processing modes and ground fault processing devices, but UShould be greater than the neutral point voltage of the power grid caused by the fluctuation of the power gridA change in (c).
IAnd the zero sequence current increment is a fixed value, and is the maximum zero sequence current value caused by the asymmetry of the power grid in the line.
The invention has the following advantages:
1. the method adopts a reverse starting processing method of neutral point displacement voltage, and solves the problem of a dead zone of high-resistance grounding faults of an asymmetric power grid.
2. The method adopts a method of comparing the zero sequence current stable increment with the power grid asymmetric zero sequence current, and solves the dead zone of the asymmetric power grid high resistance grounding line selection.
3. The method adopts a method of detecting the time period delta T, compares the stability of the relevant parameters of the detected time period, and avoids the influence of unstable disturbance grounding on grounding fault processing.
Detailed Description
Real-time detection of neutral point displacement voltage U of power distribution network during operation of power distribution networkNAnd each feeder zero sequence current In0If the voltage U is displaced from the neutral point of the power distribution network within the time period delta TNStable change occurs, and the neutral point of the power distribution network shifts voltage UNReaches a value of atNIn reverse increments, i.e. Δ U<0, but the amplitude of the change is satisfied
While, UStarting voltage fixed value for neutral point displacement voltage fault, and simultaneously enabling zero sequence current increment in any feeder line in the power distribution network to meet delta I0≥I，IIs a zero-sequence current increment constant value, and the maximum zero-sequence current I in the feeder lineMAX0≥I0B，I0BIf the current value is the maximum zero sequence current value caused by the asymmetry of the power grid, judging that the power distribution network has single-phase high-resistance earth fault, and judging that the power distribution network has single-phase high-resistance earth fault, wherein the earth fault processing device enters fault starting to process the single-phase earth fault; at the moment, the feeder line with the largest zero sequence current increment in each line is the line generating single-phase grounding; delta T is the time period of the continuous increment of the power grid parameters; u shapeShift to neutral pointVoltage failure initiates voltage scaling.
Continuous increment amplitude U of neutral point voltage of power distribution networkThe fixed value of the starting voltage of the neutral point displacement voltage fault can be set differently according to different ground fault processing modes and ground fault processing devices, but UShould be larger than the change of the neutral point voltage of the power grid caused by the fluctuation of the power grid.
I0BIs the maximum zero sequence current value caused by the asymmetry of the power grid in the line.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that several modifications and adaptations to those skilled in the art without departing from the principles of the present invention should also be considered within the scope of the present invention.
Claims (3)
1. The utility model provides a be applicable to asymmetric electric wire netting high resistance earth fault reverse start and route selection method which characterized in that: real-time detection of neutral point displacement voltage U of power distribution network during operation of power distribution networkNAnd each feeder zero sequence current In0If the voltage U is displaced from the neutral point of the power distribution network within the time period delta TNStable change occurs, and the neutral point of the power distribution network shifts voltage UNReaches a value of atNIn reverse increments, i.e. Δ U<0, but the amplitude of the change is satisfied
While, UStarting voltage fixed value for neutral point shift voltage fault, and simultaneously, enabling zero sequence current increment in any feeder line in the power distribution network to meet the condition that delta I0 is more than or equal to I，IIs a zero-sequence current increment constant value, and the maximum zero-sequence current I in the feeder lineMAX0≥I0B，I0BIf the maximum zero sequence current value is caused by the asymmetry of the power grid, the power distribution network is judged to have single-phase high-resistance earth fault, and the earth fault processing device enters fault starting to carry out fault processing on the power distribution networkProcessing the single-phase earth fault; at the moment, the feeder line with the largest zero sequence current increment in each line is the line generating single-phase grounding;
a time period for which the grid parameters are continuously increased; u shapeAnd starting voltage fixed value for neutral point displacement voltage fault.
2. The method for starting and selecting the line in the reverse direction for the high-resistance grounding fault of the asymmetric power grid according to claim 1, wherein the method comprises the following steps: Δ T should be greater than the duration of the grid disturbance.
3. The method for starting and selecting the line in the reverse direction for the high-resistance grounding fault of the asymmetric power grid according to claim 1, wherein the method comprises the following steps: u shapeDifferent settings are made according to different ground fault processing modes and ground fault processing devices, but UShould be larger than the change of the neutral point voltage of the power grid caused by the fluctuation of the power grid.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111141990A (en) * | 2018-10-17 | 2020-05-12 | 李景禄 | Ground fault identification and ground line selection method based on zero sequence current resistive component |
| CN111141991B (en) * | 2018-11-05 | 2021-12-24 | 李景禄 | Method suitable for improving high-resistance grounding fault handling capacity of asymmetric power grid |
| CN110888018A (en) * | 2019-11-11 | 2020-03-17 | 国网河南省电力公司漯河供电公司 | Asymmetric power grid high-resistance grounding line selection method based on resistive current comparison method |
| CN111781462A (en) * | 2020-06-23 | 2020-10-16 | 国网山东省电力公司聊城供电公司 | Power distribution network single-phase earth fault line selection method, system, medium and equipment |
| CN113253044B (en) * | 2020-07-10 | 2022-08-16 | 李景禄 | Intelligent judgment and processing method for single-phase earth fault in small-resistance earthing mode |
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| CN101295873B (en) * | 2007-04-28 | 2012-07-04 | 上海思南电力通信有限公司 | Medium-voltage power distribution network single-phase ground fault route selection method based on fault procedure analysis |
| CN101452038B (en) * | 2007-11-29 | 2012-01-25 | 上海蓝瑞软件技术有限公司 | Low current neutral grounding electric network single-phase earth fault diagnostic method |
| CN101369727B (en) * | 2008-10-15 | 2010-12-22 | 中国矿业大学 | Route selection method aiming at electric arc ground fault |
| CN102222889B (en) * | 2011-06-08 | 2013-11-06 | 重庆大学 | Controller for circuit asymmetrical earth fault current and control method thereof |
| CN102279349B (en) * | 2011-07-13 | 2013-10-02 | 国网电力科学研究院 | Low current grounding wire selection method based on residual current variable |
| CN103116115B (en) * | 2013-01-23 | 2015-04-08 | 福建省电力有限公司 | Network-distribution single-phase failure line selection method based on virtual active power increment maximal principle |
| CN103245892B (en) * | 2013-05-28 | 2015-11-18 | 安徽新在线科技股份有限公司 | The earthing wire-selecting method of Small Electric Current Earthing And Routing Device |
| CN106646112A (en) * | 2016-11-16 | 2017-05-10 | 安徽合凯电气科技股份有限公司 | Fast switching arc and harmonic elimination-based single-phase grounding fault line selection and location method |
| CN107300656B (en) * | 2017-06-17 | 2019-11-05 | 李景禄 | A kind of ground fault starting method based on power grid characteristic parameter incremental |
| CN107526005B (en) * | 2017-07-31 | 2020-07-07 | 李景禄 | Sudden change starting method of single-phase earth fault processing device |
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