Power system fault current measurement method designed by utilizing waveform superposition principle
A technology of fault current and superposition principle, applied in the direction of measuring electricity, measuring device, measuring only current, etc., can solve the problems of electric quantity measurement amplitude shift, protection refusal, and fault electric quantity oscillation, so as to reduce the impact and improve the Sensitivity and the effect of ensuring stable operation
Active Publication Date: 2020-09-25
KUNMING UNIV OF SCI & TECH
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Problems solved by technology
When the frequency fluctuates, the measurement method involving frequency, such as the Fourier algorithm, will not only oscillate the measured fault electrical quantity, but also cause the deviation of the measured amplitude of the electrical quantity, which will cause a comparison to the sensitivity and selectivity of fault detection. Serious impact, in extreme cases, it will even lead to protection refusal, which poses a serious threat to the stable operation of the power system
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[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of the embodiments of the present invention, rather than all embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work, all belong to the protection scope of the present invention .
[0039] Such as figure 1 with figure 2 As shown, the technical solution provided by the present invention first extracts the maximum value and minimum value of the fault current measured by the Fourier algorithm by means of waveform superposition and comparison of the current size, and uses the frequency fluctuation to compare the measured...
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The invention relates to a power system fault current measurement method designed by using a waveform superposition principle, and belongs to the technical field of power system relay protection. According to the technical scheme provided by the invention, the method comprises the steps: extracting the maximum value and the minimum value of the fault current measured by the Fourier algorithm by waveform superposition and current comparison; correcting errors measured by the Fourier algorithm through the boundary influence of frequency fluctuation on a Fourier algorithm measurement value by using the measured current extreme value, and due to the fact that impedance is inductive, further carrying out the impedance offset correction on a current value obtained after Fourier algorithm measurement errors are corrected. By performing frequency offset correction and impedance offset correction on the fault current, the influence of frequency fluctuation on fault current measurement is reduced, the sensitivity of current protection during frequency fluctuation is improved, and stable operation of a power system is effectively guaranteed.
Description
technical field [0001] The invention relates to a power system fault current measurement method designed using the waveform superposition principle, and belongs to the technical field of power system relay protection. Background technique [0002] With the rapid growth of my country's electricity demand and the rapid advancement of energy development, the characteristics of power grids have become increasingly complex. In order to optimize the grid structure and reduce the risk of AC-DC parallel operation, asynchronous networking has been implemented in some areas. The implementation of this measure has optimized the power grid structure, improved the reliability of power supply, and guaranteed the security of energy supply. But at the same time, asynchronous networking will also bring new problems, among which the problem of frequency stability is prominent. The frequency in the power grid fluctuates dynamically, especially in the island operation state, the frequency is l...
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Login to View More IPC IPC(8): G01R19/00G01R31/08
CPCG01R19/0092G01R31/086G01R31/088
Inventor 林湘孙向飞谢广宇韩坤蔡静飞
Owner KUNMING UNIV OF SCI & TECH