Control methods for cascaded STATCOM with star configuration to compensate unbalance load are proposed in this paper, both in transformerless way and transformer-used way. According to the analysis results, when the STATCOM is directly connected to the power grid without transformer, a zero-sequence voltage is injected into its output reference voltage, the amplitude of which is about twice as
... [Show full abstract] the system voltage amplitude. When it is integrated into the grid through a DY1 transformer, a zero-sequence current should be injected into in its output current reference, the range of which reaches about twice as the original current needed to be compensated. PSCAD/EMTDC is used to simulate these two conditions and the simulation results show that both methods can compensate the unbalance load effectively.