Power System Frequency Estimation With Zero Response Time Under Abrupt Transients

Abstract

The methods based on Discrete Fourier Transform (DFT) are the mainstream approaches for frequency estimation of signals in power systems. However, they exhibit unfavorable long response times when confronted with signals experiencing abrupt transients, such as amplitude or phase step changes. To surmount this challenge, a novel methodology leveraging the DFT has been designed to estimate power system signals with accuracy and responsiveness under abrupt transient conditions. The method first constructs the correlation between DFT bins and each parameter. The relationship is then harnessed to derive an unbiased estimator for sine-wave with a known step position. Afterward, we introduce a step position estimation procedure that guarantees the robustness of the estimator when dealing with abrupt transients. As a result, the proposed method achieves zero response time when confronted with arbitrary abrupt transients without loss of accuracy. The effectiveness and responsiveness of our method are evaluated through simulations that adhere to the stringent requirements of P-class phasor measurement units.