Method and device for on-line detection of dynamic performance of PMU

The invention provides a method for on-line detection of the dynamic performance of a PMU. The method for on-line detection of the dynamic performance of the PMU comprises the steps that an input signal x(t) of the input end of the PMU is obtained, and a reconstruction signal xm(t) is obtained according to the phase amplitude, the phase and the frequency which are output by the PMU; the difference signal delta xm(t) between the input signal x(t) and the reconstruction signal xm(t) is calculated; discrete Fourier transform is conducted on the difference signal delta xm(t), so that a 50 Hz power-frequency component delta X is obtained, and a comprehensive phase error (please see the specification for the symbol) is generated according to the 50 Hz power-frequency component delta X and a reconstruction signal xm(t) of the output end of the PMU; wherein Xm is the amplitude of the reconstruction signal xm(t), and |delta X| is the amplitude of the 50 Hz power-frequency component delta X. According to the method and device for on-line detection of the dynamic performance of the PMU, the frequency measurement error, the amplitude measurement error and the phase measurement error are comprehensively considered, the method and device are suitable for on-line evaluation under the condition of on-site complicated operation, a calculation result is free of the influence of harmonic waves and noise as well as suitable for dynamic and transient state processes during which frequency modulation, amplitude modulation and mutation existing on the power-frequency component.