Digital dynamic identification of power system subharmonics based on the least absolute value

Abstract This paper presents a novel dynamic technique for identifying and measuring power system subharmonics. The proposed technique is based on the weighted least absolute value. The parameters to be measured are the magnitude, the rate of decay and the frequency of these subharmonics. The identification process is split into two subproblems. In the first problem, the harmonic contents of the voltage or current waveform are identified, after which the reconstructed waveform and the error in the waveform, which is the difference between the actual and the reconstructed waveform, can be obtained. In the second problem, this error is analyzed to identify the subharmonics. Finally, the final error is obtained by subtracting the combination of the harmonic and the subharmonic contents, the total reconstructed waveform, from the actual waveform. It has been shown that by identifying these subharmonics the final error is reduced greatly. In this paper, the results obtained using the proposed algorithm are compared with that obtained using the well-known Kalman filtering algorithm. The features of the proposeld algorithm are also discussed.