A High-accuracy Algorithm of Frequency.pdf

A High-accuracy Algorithm of Frequency Measurement based on Fourier Method YE Fang Department of Electric Engineering North China Electric Power University Baoding, China xiaoluoyiluo@163.com JIAO Yanjun Department of Electric Engineering North China Electric Power University Baoding, China Abstract—Aimed to the existing problems about traditional frequency measurement method, this paper presents a new algorithm based on Fourier frequency measurements. First, according to the error of the original Fourier frequency measurement, the amendatory coefficient is adjusted, an improved method based on Fourier correction coefficient frequency measurement is proposed. Then, because error of the Fourier algorithm is larger when the frequency offset, interpolation algorithms have been proposed based on the true frequency of the signal. In order to improve the signal what contains harmonic component frequency measurement accuracy, iterative of the frequency until the algorithm converges or reach the maximum number of iterations. Finally, the algorithm is verified, the errors of the calculation when there is harmonic component and isnt harmonic component in the signal are compared. The practice prove that precision of the algorithm is effectively improved, the amount of calculation is significantly reduced, a high precision tracking system frequency is achieved, the requirement of real-time performance of the power system is completely satisfied. Keywords-frequency deviation; Fourier algorithm; amendatory coefficient; Newton interpolation; iteration I. INTRODUCTION The frequency of the power system is an important parameter, frequency deviation is an important indicator what reflected the power quality. Accurate measurement of the actual frequency is must be important to ensure stable operation of power systems. The Fourier algorithm is widely used in practice, because it has a strong anti-interference and filter characteristics [1-5]