Power system fault signal detection and waveform identification method based on optimization algorithm

Abstract

The invention discloses a power system fault signal detection and waveform identification method based on the optimization algorithm. The power system fault signal detection and waveform identification method includes the following steps: firstly, collecting power system signal data through a current transformer, connecting the current transformer with a data collecting card, converting the power system signal data through the data collecting card into digital signals, sending the digital signals to an upper computer, then, estimating fundamental components (including the amplitudes, the frequency and the phases), harmonic components (including the amplitudes, the frequency and the phases of harmonic waves), and exponential decay direct current deviations (including amplitudes and time constants), and a fault initial point with the optimization algorithm on the upper computer, and finally reconstructing power system signals according to the estimated parameters, wherein the optimization objective is that the least square variance error between the reconstructed signals and actually-measured signals is minimum. According to the power system fault signal detection and waveform identification method, the signal parameters under the fault-free condition and the fault condition can be accurately estimated; detection of the fault initial point and recognition on fault signal waveforms are carried out at the same time, and the two tasks can be completed in a sampling window with the long half-circle through the optimization algorithm.

Description

Technical field [0001] The present invention relates to the technical field of power system protection, in particular to a power system fault signal detection and waveform recognition method based on an optimization algorithm. Background technique [0002] Relay protection refers to the protection of the normal operation of the entire system by isolating the faulted part from the power system after the power system fails. The relay protection system is required to respond quickly and correctly when the fault occurs to ensure that the fault is caused The loss is minimized. The power system fault signal appears as a sudden increase in signal amplitude and contains harmonic components. The basic principles of power system relay protection have been used for more than half a century and have not changed. Almost all algorithms are based on integral transforms, such as Fourier transform and wavelet transform. One of the main disadvantages of the integral transformation is that it can...

AI Technical Summary

Problems solved by technology

The first type of method has higher requirements on the filter and requires a larger amount of calculation

The second type of method uses the first two terms of the Taylor expansion to replace the exponential component, and then uses the minimum mean square error curve fitting technique to estimate the harmonic component of the fault signal. The disadvantage is that the second-order Taylor expansion will introduce a large error, and the curve fitting The calculation efficiency is low

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