Mitigation of forced oscillations using VSC-HVDC supplementary damping control

Forced oscillation has become one of the main power grid dynamic stability problems, which can cause high amplitude oscillation of the active power in the tie line. The supplementary damping controller (SDC) of the voltage source converter based high voltage direct current (VSCHVDC) has demonstrated its effectiveness in suppressing inter-area modal oscillation, but its role in mitigating forced oscillation has not been studied in the literature. In this paper, an active disturbance rejection control (ADRC) based SDC of the VSCHVDC is designed to mitigate forced oscillations. The mitigation effect of the ADRC based SDC on forced oscillation is compared to the traditional one under different scenarios. Simulation results of four-machine two-area AC-DC hybrid system indicate that the traditional SDC is sensitive to the frequency of the disturbance source, and the reactance between the disturbance source and the VSCHVDC, whereas the ADRC based SDC can effectively mitigate the forced oscillation whatever the frequency of disturbance source is near or far from the inter-area natural frequency, and its mitigating effect is almost not affected by the reactance between the disturbance source and the VSCHVDC.