Frequency and Harmonics Estimation for Electric Power System Using Subspace Method

Frequency is a very critical and sensitive parameter in an electrical power system. Any variation in a power system can be traced back to a change in the electric power system's frequency. Moreover, with the rapid development of power electronics, the security, reliability, stability, and operational efficiency of electric power systems has deteriorated dramatically due to the injection of harmonic components in the power system. Therefore, the need to control the frequency by first determining the frequency in an electrical power system is needed. The method proposed here for the estimation of power system frequency and its harmonics is based on Rank Revealing QR Factorization method (RRQR) in conjunction with Multiple Signal Classification (MUSIC) algorithm. The experimental results will demonstrate the effectiveness of the proposed method in detecting the fundamental frequency, even and odd harmonic frequencies, and interharmonics against the classical approach of the Fast Fourier Transform (FFT) algorithm.