Phasor Estimation Algorithm for a Decaying AC Component using Pronys Method

H.-K. Kim, S.-H. Kim, C.-Y. Choi, C.-H. Kim, D.-G. Lee, and S.-H. Kang (Korea)


Prony’s Method, Micro Grid, Phasor Estimation


The power capacity of a wind generator is usually much smaller than that of a large thermal power generator. The output voltage and current of a small power generator easily oscillate when a fault occurs in the close proximity to a generator. The signal oscillations can cause the maloperation of a digital relay. To handle this kind of difficulty coming from the time-varying characteristics of the signal, an accurate method to estimate the phasor of a time-varying signal is required. To estimate accurately the phasor of a signal having an exponentially decaying envelope, a phasor estimation algorithm based on the Prony’s method is proposed in this paper. For the purpose of the stabilization of the output of the proposed phasor estimation algorithm, a 3rd order pre-conditioning low pass filter which can do the extra role of anti-aliasing filter is used. In series of tests, the proposed algorithm shows accurate and stable results.

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