Method and system for measuring frequency of sine wave signal in power system

Abstract

The invention discloses a method and system for measuring the frequency of a sine wave signal in a power system. The method includes: inputting a sampling data sequence obtained by sampling the sine wave signal as an excitation signal into a point frequency filter; filtering the generated point frequency The amplitude of the data sequence is normalized to generate an instantaneous sine wave signal sequence with normalized amplitude; from the instantaneous sine wave signal sequence, two discrete signals with the closest distance to the start zero-crossing point and the closest distance to the end zero-crossing point are selected Two discrete signals of two discrete signals; the sampling value of four discrete signals selected is converted into the cycle of the instantaneous sine wave signal sequence; the cycle is converted into the instantaneous frequency of the instantaneous sine wave signal sequence; according to the sine wave signal The corresponding relationship between the frequency, the point frequency and the instantaneous frequency is used to convert the instantaneous frequency into a measurement frequency of the sine wave signal. By implementing the invention, the frequency of the sine wave signal with higher precision can be measured.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a method and system for measuring the frequency of a sine wave signal in a power system. Background technique [0002] In the practice of modern power engineering, the development of high-precision power instruments and the application of a large number of new technologies in the power system have higher and higher requirements for the measurement accuracy of signal frequency. A common method for measuring the frequency of low-frequency signals is a zero-crossing algorithm. This method calculates the frequency of the waveform by detecting the zero-crossing point of the signal waveform and using the time interval of one or several cycles of the zero-crossing point. [0003] However, in the case of noise interference, the accuracy of the frequency value measured by the above-mentioned measurement of the frequency of the low-frequency signal is low, and it is difficult to a...

AI Technical Summary

Problems solved by technology

[0004] Based on this, it is necessary to provide a method and system for measuring the frequency of a sine wave signal in a power system for the problem of low accuracy of the frequency value measured by measuring the frequency of the low-frequency signal.

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