Application of MUSIC Algorithm to Power Quality Analysis:Detecting Inter Harmonic Components

Power quality involves how close the voltage waveform is to being a perfect sinusoid with a constant frequency and amplitude [4]. When fluctuations in the power supply occur there is a chance of occurrence of the interharmonics. The MUSIC algorithm is used to estimate the frequencies and amplitudes of the interharmonics of the power signal. In this paper, a synthetic signal consisting of harmonics and interharmonics is considered. The synthetic signal is assumed to possess five harmonics(from second to fifth harmonics) of fundamental frequency fifty hertz and two interharmonics at eighty two hertz and one hundred and eighty two hertz buried in additive white noise having zero mean and unit variance with a sampling frequency of two thousand hertz. The signal is said to possess different amplitudes and phase angles. The true value of amplitudes and frequencies is compared with that of the estimated values and an accuracy of 99.90 percentages is obtained. MUSIC algorithm is very robust in estimating interharmonics and hence it is said to be a “Super Resolution” technique in estimating the frequencies. The simulations are carried out using MATLAB software.