Fault Characteristics and Fault Handling Strategies of MMC-HVDC for Onland Renewable Energy Base Transmission

In recent years, China has accelerated the development of new energy power generation bases in desert and gobi regions, with Modular Multilevel Converter-based High Voltage Direct Current (MMC-HVDC) transmission as a key technology. As these projects are still in the planning and construction phase, investigating typical faults is crucial. This paper discusses the fault characteristics and handling strategies of MMC-HVDC for onland renewable energy base transmission. It introduces the fundamentals of MMC-HVDC in this application, analyzes fault characteristics, and proposes fault handling strategies for multi-terminal MMC-HVDC. The study reveals that both AC and DC faults can lead to overvoltage and overcurrent, with AC faults at the receiving end causing the most severe overvoltage. DC choppers can effectively suppress DC overvoltage caused by AC faults at the receiving end.