Research on Optimal Allocation Control Strategies for MMC-UPQC by Considering Economical Evaluation

The integrating of new energy and the increasing application of non-linear loads cause such phenomenon that the capacity compensated in load side exceeds the parallel compensation capability of unified power quality conditioner for modular multilevel converter (MMC-UPQC). In this paper, two optimized control schemes for compensating reactive power and negative sequence and harmonic current are proposed. One is the priority allocation control strategy that focuses on priority assignment, and the other is multi-objective optimized allocation control strategy based on self-adaptive penalty genetic algorithm that pays more attention on comprehensive compensation. The index to evaluate the average economic losses for power quality events are chosen as the standard for priority selection in scheme I and the weight coefficients in scheme II. In the PSCAD/EMTDC simulation environment, simulation results show that optimized compensations can be realized by both proposed optimized control strategies to improve current power quality under above MMC-UPQC limited situation.