A Three-Terminal Hybrid HVDC System based on LCC and Hybrid MMC with DC Fault Clearance Capability

摘要

In this paper, a three-terminal hybrid HVDC system based on LCC and hybrid MMC is proposed, which has the ability of DC fault clearance. The system combines the merits of hybrid HVDC system and multi-terminal HVDC system, which is able to deliver bulk renewable power to multiple receiving power grids at a relatively lower cost. By utilizing hybrid MMC as the inverters, the system has the capability to ride through DC faults. The topology and the operating characteristics of the system are introduced in detail. The design of the hybrid MMC is analyzed. The control strategy and the DC fault ride through strategy are proposed. Finally, the model of three-terminal HVDC system is built in PSCAD / EMTDC. The simulation verifies the effectiveness of the control strategy and the DC fault ride through strategy. The results indicate that this kind of HVDC system has a good application prospect in bulk power transmission to the multiple remote receiving regional power grids and the DC fault ride through ability proposed for the system operates well.