Fault current limiting method for short circuit fault early detection

Abstract

The invention discloses a fault current limiting method for short circuit fault early detection. The method includes the steps of firstly, conducting A / D sampling on a current signal at a fixed sampling frequency, and conducting algorithm filtering on the sampling signal noise of the current signal; secondly, conducting algorithm processing on the filtered signal, extracting the current signal characteristic quantity and the voltage change ratio, and conducting short circuit fault early detection; thirdly, through short circuit fault early detection, judging whether the current signal characteristic quantity and the voltage change ratio which are obtained at present exceed a threshold value of a short current fault or not, if yes, judging that the short circuit fault occurs to a circuit, instantly triggering the FCL and continuing to conduct the next time of detection, and if not, restarting the detection. According to the method, firstly, A / D sampling is conducted on the circuit current, and noise interference is filtered out through the software algorithm; secondly, early detection and recognition of the fault are conducted through a signal singularity characteristic extraction algorithm, a trigger signal is sent out to control triggering of the FCL after recognition is conducted, and therefore early limitation of the short circuit current is achieved.

Description

technical field [0001] The invention belongs to the field of electric circuit fault detection and limitation, in particular to a fault current limiting method for early detection of short-circuit faults, which relates to early detection identification and limitation of short-circuit faults. Background technique [0002] Short-circuit fault is one of the most common and harmful fault types in power distribution system. With the rapid increase of power system load and the continuous operation of large-capacity units, the short-circuit current of power grids of various voltage levels continues to increase. Strong short-circuit current puts forward higher requirements on the dynamic and thermal stability of lines, equipment and switches themselves. However, it is very uneconomical or even impossible to increase the breaking capacity of circuit breakers or fuses indefinitely and to improve the dynamic and thermal stability of lines and equipment indefinitely, and the limit break...

AI Technical Summary

Problems solved by technology

This can greatly improve the current-limiting performance of short-circuit protection appliances and FCL, reduce the threat of short-circuit current to the power system and its electrical equipment, and reduce the requirements for dynamic and thermal stability of lines, equipment and switches themselves. The judgment time of the conventional short-circuit criterion is too long, which leads to shortcomings such as poor short-circuit current limiting effect

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