Fast algorithm for estimating power frequency phasors under power system transients

Abstract

Power frequency phasors are widely used in the measurement, analysis, control and protection of power systems. When disturbances occur in such systems, power frequency phasors must be estimated quickly to ensure an accurate restoration to normal operation. Hence, a fast and accurate estimation algorithm would be a significantly useful tool. In consideration of the composition of transient signals in power systems, a novel algorithm for power frequency phasor estimation is proposed. Based on the double matrix pencil method, a unitary reference matrix of complex-valued exponential signals is formed. The power frequency phasor estimation is then transformed to a brief multiplication of matrices. Thus, the QR decomposition, generalised eigenvalue calculation, and secondary estimation can be avoided and no complex multiplication is introduced. Therefore, the computational efficiency of the proposed method is improved compared with previous estimation techniques. Analytical and experimental investigations show that the proposed algorithm can extract power frequency phasors accurately, stably and quickly under power system transients.