Individual-phase decoupled P-Q control of three-phase voltage source converter

Individual-phase control has six control degrees of freedom: P- and Q-control for each phase. The six control degrees are applied to a distribution static compensator (D-STATCOM): (i) to support the AC voltages against voltage droop arising from weak transmission lines; (ii) to balance the active and reactive powers at the sending-end although the three-phase load is unbalanced; and (iii) to balance the voltages across the unbalanced load. A second contribution is a method to suppress DC voltage imbalance of D-STATCOM capacitors caused by zero sequence transients. Proof of concept is by simulations. The simulation tool used is EMTDC-PSAD.