Comparison of Direct and Indirect Current Control Strategy for DSTATCOM

Voltage regulation of weak distributions is a challenging problem. The fast response of the distribution static compensator (DSTATCOM) makes it an attractive alternative for voltage fluctuation and flicker mitigation. However, operation of DSTATCOM with weak networks needs careful attention to avoid unexpected over-current problems under widely varying load conditions. Large rapid industrial load changes will produce voltage unbalance, voltage amplitude sudden change, voltage phase jumps and harmonic current in the PCC. This paper explores their unfavorable influences on both indirect and direct current control strategy for DSTATCOM item by item and points out that direct current control strategy is more robust and works well under all the four conditions.