Improved synchrophasor measurement to capture sub/super-synchronous dynamics in power systems with renewable generation

The existing phasor-measurement unit (PMU) and wide-area measurement system (WAMS) based on the fundamental synchrophasors are insufficient to accurately capture the dynamics of sub/super-synchronous resonance or oscillation (SSR/SSO). To address this issue, this study proposes a new method for the simultaneous and precise measurement of the fundamental and multiple sub/super-synchronous harmonic phasors. It improves the classic discrete Fourier transform (DFT)-based method by adding adaptive frequency detection, modal filtration and phasor correction and compensation. Thus, in the context of SSR/SSO, the phasors of both fundamental and interharmonic components can be precisely obtained at local PMUs and the control/data centre of WAMS. The basic procedures and the prototype implementation of the method have been elaborated, and the performance has been examined with simulation signals as well as the field data recorded from an actual SSO incident. The results have verified its high precision, noise immunity and fast response.