Subsynchronous Oscillation Monitoring and Alarm Method Based on Phasor Measurements

摘要

With the large-scale grid connection of new energy, a large number of power electronic devices installed introduce sub-/super-synchronous inter-harmonics into power signals, resulting in frequent occurrence of subsynchronous oscillations (SSO). The subsynchronous oscillation will cause serious harm to generator sets and power systems, so its online monitoring and accurate alarm are crucial to the safe and stable operation of them. Phasor measurement units (PMUs) can realize dynamic real-time monitoring of power systems. Based on PMU phasor measurements, this paper proposes a method for SSO online monitoring and alarm on the main station of PMU. Firstly, based on PMU current phasor amplitude data, FFT frequency spectrum analysis is performed to obtain subsynchronous frequency components. Secondly, the SVM learner is trained to obtain the amplitude threshold, then filter out safe components and retain harmful ones. Finally, the adaptive duration threshold is determined according to frequency susceptibility, amplitude attenuation and energy accumulation to decide whether to send out an alarm signal. Experiments based on field data verify the effectiveness of the proposed method.