Synchronverter-based operation of STATCOM to Mimic Synchronous Condensers

The operating principles of static synchronous condenser (STATCOM) are similar to that of a rotating synchronous condenser. However, so far, most controlling methods proposed for STATCOM have not taken into account the internal characteristics of rotational synchronous machines. In this paper, following the idea of synchronverters, the controller for a STATCOM is designed according to the mathematical model of synchronous generators that are operated in the compensator mode. As a result, no phase-locked loop (PLL) is needed. Moreover, a third operation mode, i.e. the droop control mode (or the D-mode in short), is introduced to the operation of STATCOM, in addition to the conventional voltage regulation mode (or the V -mode in short) and the direct Q control mode (or the Q-mode in short). This allows parallel-operated STATCOMs to share reactive power properly. The proposed control strategy is verified with simulations in MATLAB/Simulink/SimPowerSystems.