Rapid short-circuit current discrimination method and discrimination system based on combination of current instantaneous value and current change rate

Abstract

The invention discloses a rapid short-circuit current discrimination method and discrimination system based on combination of a current instantaneous value and a current change rate. The method comprises the following steps: collecting and obtaining a to-be-discriminated current; calculating an absolute value of a current instantaneous value and an absolute value of a current change rate of the to-be-discriminated current; and determining the to-be-discriminated current to a short-circuit current under the condition of meeting the following two criteria simultaneously: setting a current instantaneous value criterion expression to be: |i(t)|being larger than or equal to alpha.|IS| and setting a current change rate criterion expression to be: |di(t)/dt| being larger than or equal to beta.|Dzd|. In the current change rate criterion expression, the i(t) expresses a to-be-discriminated current instantaneous value, the Is expresses a current instantaneous value setting value, the Dzd expresses a current rate change setting value, the alpha expresses a current instantaneous value setting adjustment coefficient, the beta expresses a current change rate setting adjustment system; and the alpha is less than 1 and the beta is less than 1. According to the invention, the influence of the fault phase angle is small; and the fault detection time is always in a required range.

Description

technical field [0001] The invention belongs to the technical field of power system relay protection and fault treatment, and in particular relates to a short-circuit current rapid discrimination method and a discrimination system based on the combination of current instantaneous value and current change rate. Background technique [0002] With the maturity of the fast switch using fast eddy current drive technology, it provides a simple and practical solution to solve the problems of sensitive load disconnection caused by excessive short-circuit current and voltage sag; in addition to the fast action speed of the fast switch, all The short-circuit fault detection employed should also be realized within milliseconds. [0003] The traditional fault detection method generally adopts the Fourier method. Even if the half-wave Fourier method is used, at least 10ms of data needs to be collected before judgment can be made, which cannot meet the requirements of rapid identification...

AI Technical Summary

Problems solved by technology

[0003] The traditional fault detection method generally adopts the Fourier method. Even if the half-wave Fourier method is used, it needs to collect at least 10ms of data before making a judgment, which cannot meet the requirements of rapid identification.

[0004] Existing fast discrimination methods are generally based on the instantaneous value of current or the rate of change of current for fault detection, and the reliability is not high enough

The method

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