Fault current detection method and device for adaptive filtering DC component

Abstract

The present invention provides a fault current detection method and device for an adaptive filtering DC (direct current) component. According to the method and the device, through the digital processing of a collected current signal, a corresponding current digital signal is obtained and then the digital filtering processing is carried out, a current DC component is adaptively separated from faultcurrent, the current DC component is filtered, a current fundamental frequency component is extracted to carry out fast fault current detection, thus the fault current detection precision can be ensured, and the problems of a large detection error, relay protection misoperation and the like caused by an impact or oscillation phenomenon generated by the current DC component in the fault current detection process are avoided. The method and the device are widely applied to a digital relay protection device so as to conveniently detect and remove faults in a power system, and the problems of a large error, low accuracy and easy relay protection misoperation of the fault current detection in the prior art are solved well.

Description

technical field [0001] The invention relates to the technical field of fault current detection, in particular to a fault current detection method and device for self-adaptive filtering of DC components. Background technique [0002] The fault current signal processed in the digital relay current detection device includes a DC component, a fundamental frequency component and a harmonic component. It needs to use a filtering algorithm to reduce the influence of the DC component and harmonic component in the fault current, so as to detect the fault condition more accurately. Different algorithms have significant differences in accuracy, response time and computational load. Conventional discrete Fourier transform (DFT) can reduce harmonic components and is often used to obtain fundamental frequency components, but it cannot filter out DC components and Less accurate. The DC component is a non-periodic signal. If the fundamental frequency component is not filtered out, shock or...

AI Technical Summary

Problems solved by technology

Different algorithms have significant differences in accuracy, response time and computational load. Conventional discrete Fourier transform (DFT) can reduce harmonic components and is often used to obtain fundamental frequency components, but it cannot filter out DC components and less accurate

The DC component is a non-periodic signal. If the fundamental frequency component is not filtered out, shock or oscillation may occur, which will cause a large error in the acquisition of the fundamental frequency component, resulting in inaccurate current acquisition by the current detection device, which in turn causes Serious consequences such as relay protection malfunction

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