A Novel Detection Method for Supersynchronous Resonance From Synchrophasor Data

Subsynchronous resonance (Sub-SR) is traditionally caused by turbine generators. In recent years, a new type of Sub-SR has occurred that is related to inverter-based resources (IBRs). In those events, supersynchronous resonance (Sup-SR) accompanied Sub-SR, a phenomenon commonly called frequency coupling. It is thus of great significance to detect whether there is a supersynchronous component, which can help to perform postincident analysis and design a mitigation strategy. This paper uses synchrophasor data provided by phasor measurement units (PMUs) to detect the Sup-SR. Due to the limitation of the reporting rate of PMUs, spectrum aliasing occurs between Sub-SR and Sup-SR, which imposes great challenges for detection. To address this issue, the influence of Sup-SR and Sub-SR on the positive and negative spectra of synchrophasors is analyzed. The results show that Sup-SR primarily affects the negative spectra of synchrophasors. Based on this finding, the difference between the measured spectra and the theoretical spectra with pure Sub-SR is utilized to detect Sup-SR. An adaptive threshold is further proposed using a histogram-based statistical approach to enhance the detection accuracy. Case studies demonstrate that the proposed algorithm can accurately detect the presence of Sup-SR from synchrophasor data.