一种快速的软件频率计算方法

频率测量是电力系统测控装置和保护装置的基本功能.频率测量的快速性和准确性将深度影响电力系统测控和保护装置的性能,从而影响到电力系统的稳定性.为提高频率测量的快速性,提出了一种全新的频率测量算法.该算法可以在5/4周波内测量出被测对象的频率,具有极强的实时性.首先对计算傅里叶级数实部的核函数进行移相.然后分别采用移相前后...

A fast software frequency calculation method

Frequency measurement is the basic function of power system measurement and of a control device and protection device. The rapidity and accuracy of frequency measurement will seriously affect the performance of power system measurement and the protection device, thus affecting the stability of the power system. In order to improve the rapidity of frequency measurement, a new frequency measurement algorithm is proposed. The algorithm can measure the frequency of the measured object in 5/4 cycle, and has strong real-time performance. First, the kernel function for calculating the real part of a Fourier series is phase shifted. Then the kernel function before and after phase shift is used to Fourier transform the original signal to obtain the real part of the signal. After that, the signal frequency is calculated by using the time difference between the zero crossing of two real part signals. Finally, the algorithm is verified by Matlab simulation and actual measurement of a protection device. The tests show that the proposed algorithm meets the accuracy requirements; the tracking speed of gradually changed frequency is greatly improved compared to that of existing algorithms.This work is supported by the Science and Technology Project of China Southern Power Grid Co., Ltd. (No. ZBKJXM20180500).