Dual-Band PSS Design for the Joint Mitigation of Electromechanical and Low-Frequency Power Electronic Oscillations in a PV-Dominated Power System under the VSG Control

The large integration of inertia-less renewable energy sources (RESs), such as solar photovoltaic (PV) systems, has brought about several stability challenges for the power grid. The virtual synchronous generator (VSG) technology has emerged as a promising solution for addressing the low-inertia problem of a renewable-driven power system and improving its large-signal stability. However, as the number of VSG-controlled PV plants increases, a new type of oscillation emerges in the system because of the dynamic interactions between the VSG controller and the current controller of a PV inverter. In order to damp out such newly observed low-frequency power electronic oscillations, together with the traditional electromechanical oscillations, a renewable-effective dual-band oscillation damping power system stabilizer (REDBOD-PSS) is proposed in this paper. Here, the term dual-band basically refers to using a twin PSS architecture to independently and non-interferingly damp out system oscillations over two different frequency bands. The performance of the proposed REDBOD-PSS is thoroughly validated through multiple case studies on the IEEE 68-bus 16-machine power system. Case studies reported involve both frequency- and time-domain analyses, and the time-domain simulation are carried out on the MATLAB/Simulink platform considering various types of disturbance to the system.