A wavelet approach to real time estimation of power system frequency

Frequency is an important parameter of electric power system, also a key index of power quality. A new approach to the estimation of power system frequency using wavelet transform is proposed in this paper. This approach adopts a complex wavelet function as band pass FIR filters to estimate the instantaneous average frequency in its pass frequency band. Besides this, a recursive algorithm of continuous wavelet transform (CWT) based on polynomial type wavelet function is also presented, by which this wavelet approach is very suitable for real time implementation. The performance evaluation exhibits a high robustness and estimation accuracy of the proposed technique over a wide range of frequency deviation. It is further shown that this approach is capable of tracking power system frequency under dynamic conditions, and is immune to the effects of harmonics and decaying DC component.