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A Method for Handling Abnormality of Differential Protection Sampling Data

A technology of abnormal processing and sampling data, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of current differential protection malfunction, sampling data distortion, phasor amplitude and phase changes, etc., to achieve high reliability, The effect of reducing influence and preventing malfunction

Active Publication Date: 2018-01-19
STATE GRID CORP OF CHINA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Sampling data is the basis of protection, and its quality has a close influence on the action performance of protection. However, since there are multiple links in data collection, the data collection and transmission links generally may cause distortion of the sampling data, and the distorted data will affect the performance of the Fourier transform. As a result, the phasor amplitude and phase change, which may cause the current differential protection to malfunction
[0003] The existing current differential protection handles the distorted sampling value by comparing the size relationship between several sampling points of the current on the same side of the line, determining the distorted data and "discarding" it, but when there are multiple consecutive distorted data , unable to eliminate all the distortion data, which may cause misoperation of current differential protection in severe cases

Method used

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  • A Method for Handling Abnormality of Differential Protection Sampling Data

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Embodiment 1

[0031] Such as figure 1 Shown, the method step of the invention of this example is as follows:

[0032] (1) Collect the current data I of each phase on both sides of the line mi (K) and I ni (K), (i=A, B, C three-phase), K is time;

[0033] (2) Calculate the current data I of each phase on one side of the transmission line mi (K) and the current data I of each phase with a difference of one cycle mi (K-T) difference, that is, I mi (K)-I mi (K-T);

[0034] Determine the current data I of each phase on the other side of the transmission line ni (K) and the current data I of each phase with a difference of one cycle ni (K-T) difference, that is, I ni (K)-I ni (K-T);

[0035] (3) When I mi (K)-I mi (K-T)>ΔI set , and I ni (K)-I ni (K-T)>ΔI set , go to step (7), where the mutation amount is fixed at ΔI set ;

[0036] (4) When I mi (K)-I mi (K-T)>ΔI set , and I ni (K)-I ni (K-T)set , calculate I mi (K) phase angle θ;

[0037] (5) If 0°≤θ≤45° or 135°≤θ≤225° ...

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Abstract

The invention relates to a method for the sample data exceptions of differential protection. The method comprises the following steps: identifying the sample data exceptions by comparing the sudden changes of sampling values at the both sides of a circuit, simultaneously, judging the phases of data exception points and processing the phases respectively, when the phases of the sampling values are located in [0 degree, 45 degrees] or [135 degrees, 225 degrees] or [315 degrees, 360 degrees), setting the sampling values to 0, when the phases of the sampling values are located in (45 degrees, 135 degrees) or (225 degrees, 315 degrees), reducing the sampling values to 1 / 10 thereof, calculating a current differential protection criterion on this basis, and judging fault positions. The method for the sample data exceptions of the differential protection provided by the invention is capable of preventing the maloperations of the current differential protection, which are caused by the data exceptions.

Description

Technical field: [0001] The invention relates to a data abnormality processing method, in particular to a differential protection sampling data abnormality processing method. Background technique: [0002] In the field of power system relay protection, because the current differential protection is not affected by oscillation and has a fast action speed, it is widely used in the main protection of transmission lines. Sampling data is the basis of protection, and its quality has a close influence on the action performance of protection. However, since there are multiple links in data collection, the data collection and transmission links generally may cause distortion of the sampling data, and the distorted data will affect the performance of the Fourier transform. As a result, the magnitude and phase of the phasors change, which may cause misoperation of the current differential protection. [0003] The existing current differential protection handles the distorted sampling...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
Inventor 王兴国周泽昕杜丁香李仲青李伟姜宪国
Owner STATE GRID CORP OF CHINA