The compensation control of reactive power and three phase unbalance load based on the method of sequence component

A static var compensator (Static Synchronous Compensator, STATCOM) is compensated reactive power and three phase unbalance load for the distribution grid. According to analyzing the positive sequence equivalent circuit and negative sequence equivalent circuit under the three phase unbalance load of distribution grid, using the symmetrical component method and superposition principle, a new cascade loop control strategy of positive sequence current and negative sequence current is proposed. Using δ-θ control, the positive sequence loop is compensating reactive power of distribution grid, and maintains stability of STATCOM DC voltage. Using ε-θ control, the negative sequence loop is used to compensating three phase unbalance load of distribution grid. Simulation results are presented to verify the validity of the proposed control strategy.