Comparison of synchronous condenser and STATCOM for inertial response support

This paper shows a comparison between synchronous condenser (SC) and STATCOM in terms of inertia frequency response (IFR) with synchronous generator (SG). It has long been argued that, as a rotating-mass-based reactive power compensation device, SC will contribute to the total inertia of the network from its stored kinetic energy. Whereas, its counterpart, the voltage source converter (VSC) based STATCOM, will only supply reactive power and maintain voltage balance. However, the energy stored in the dc-link capacitor of the STATCOM, especially the cascaded inverter based STATCOM whose dc-link capacitance is relatively large, if properly controlled, can also contribute to the IFR. A matlab/Simulink model of SG equipped with SC and STATCOM is presented in this paper. It is demonstrated that STATCOM can provide competitive or even better IFR during disturbance condition. Both theoretical and simulated results are provided.