Fast recognition system and method for power system fault current

Abstract

The invention relates to a fast recognition system and method for power system fault current. Signals for current in a circuit and current change rate transient value are sampled in real time, so that a first characteristic signal in direct proportion to current first-order differential and a second characteristic signal in direct proportion to current second-order differential are obtained; the two characteristic signals at a same time point are calculated according to the theory of trigonometric function, so that the peak of steady-state short-circuit current is obtained. The fast recognition system and method for power system fault current has the advantages that the differential value of short-circuit current is used for calculation, so that the effect of aperiodic components upon calculation results is effectively filtered; short-circuit current can be recognized quickly and quantitatively for less than 3ms of response time; quantitative recognition is convenient for classifying short-circuit faults according to short-circuit levels.

Description

technical field [0001] The invention relates to the field of fault current detection, in particular to a fault current rapid identification system and method, which are mainly used for rapid detection of short-circuit faults in power systems and other industrial power systems. Background technique [0002] When a short-circuit fault occurs in the power system or the power system of an industrial user, in order to minimize the adverse effects caused by the short circuit, it is required that the relay protection or other auxiliary electronic devices can identify the short-circuit fault at the fastest speed and accurately predict the short-circuit current level, and control the action of circuit breakers or other breaking devices according to a certain strategy at the first time to cut off the fault circuit. The traditional short-circuit fault identification method needs to use the Fourier transform to extract the fundamental wave component, and the identification speed is rela...

AI Technical Summary

Problems solved by technology

Using a pure hardware circuit, using the current i and the current change rate di / dt two criterion logic operations to identify whether the fault current exceeds the preset threshold to identify the fault current, this method can achieve rapid identification, but it is It can only know whether the fault current exceeds the threshold but cannot know the exact magnitude of the fault, which is limited in practical application

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