Feasibility Analysis of Full Power Variable Speed Operation of Pumped Storage Power Station Based on M3C Converter

Abstract

The unit of variable-speed pumped storage can realize the stepless regulation of peak shaving and valley filling in power grid, improve the hydraulic performance of pump turbine, expand the operation range and improve the operating efficiency of the unit. The realization method of high-power variable-speed pumped-storage unit has been one of the key and difficult research works at this stage. In view of the complex excitation system of the AC excitation unit and only suitable for new applications, this paper proposes a full-power variable speed scheme in which multilevel matrix converter (M3C) topology converter are connected in parallel on both sides of the main circuit breaker of the existing pumped-storage unit. From the three dimensions of voltage stress, current stress and thermal stress of power electronics, the feasible scheme of using M3C converter to realize full power variable speed operation of pumped storage unit is analyzed. The feasibility of the proposed full-power variable-speed scheme is shown by comparing the pumping-storage starting strategies at constant speed and full-power variable-speed pumping-storage and the converted starting time of the water pump. The correctness of the proposed scheme is verified by the dynamic model experiment.