Research on the Impact of Crystal Oscillator Frequency Deviation on PMU Measurement under System Oscillation

Phasor measurement unit (PMU), which could provide high-frequency phasors including the amplitude and phase angle synchronized with Global Positioning System (GPS)/ BeiDou Navigation Satellite System (BDS) signal, plays vital role in dynamic monitoring of power system. However, if the GPS/BDS signal could not be received, the time of PMU, which is depending on the crystal oscillator, would have a measurement deviation provided by the frequency deviation (FDCO) of crystal oscillator. Meanwhile, due to high proportion of new energy power generation and power electronic equipment in power system, power system oscillation occurs frequently, and the measurement problems under oscillations have also become a hot topic of concern. Therefore, this paper analyzes and deduces the impact of constant crystal frequency deviation on PMU measurement when the system is oscillated. First, in the oscillation state, the phasor measured by the PMU in the case of the FDCO exists is derived. Then, the detailed analysis of the impact of different value of the FDCO on the PMU measurement is carried out. Finally, the impact of FDCO on angle and amplitude data of PMU measurements are verified with simulation, when the FDCO is small and large, respectively.