Study On The Control Strategy For Compensating Unbalance Loads

More and more unbalanced loads, such as the steel-making industry three arc furnaces and electrical railway, are used, which will lead to the power system's unbalance. The power system's unbalance is a serious threaten to the power system security, moreover it will also reduce the power quality. The SVC can not only compensates the reactive power, but also dish the negative sequence current produced by the unbalance loads, which mostly depend on the control scheme.This paper firstly introduce the basic theory about the asymmetry compensating, then the algorithm based on the symmetry components for obtaining the compensating admittance is analyzed. Hilbert filter bank was used to get a pair of orthogonal signals required in the calculation of instantaneous reactive power. In order to reduce the SVC capacity requirement, a scheme to control the unbalance factor after compensating is proposed in the paper.The difference between the direct compensating admittance control and the compensating admittance increment control strategy is compared by the SVC simulation. A SVC experiment system with a 80cl96_based controller was also developed. Simulation and experiment results verify the correctness and feasibility of the proposed scheme.