Discrete-time analytic signals for power system phasor and frequency tracking

Abstract

The tracking of phasor and frequency is becoming vital in power networks ranging from interconnections monitored via wide-area measurement systems to isolated microgrids operating autonomously. However, despite the progress in phasor measurement technology, the performance of the signal processing module is still an active research area due to the challenge of phasor and frequency estimation under dynamic conditions. This paper proposes a signal processing technique for frequency and phasor estimation based on discrete-time analytic (DTA) signals. First, a new method is proposed for computing the DTA signal directly in the time domain. The DTA signal is then approximated using a first-order Taylor series expansion that forms the basis of the tracking method, essentially ensuring that the DTA signal is generated at the exact value of the estimated frequency. The proposed method is accurate as it is based on time-domain least squares estimation; it also meets real-time computing requirements because it employs a single factorization of the gain matrix to achieve the solution. Numerical results are reported under both steady-state and dynamic conditions, showing the proposal’s viability.