Availability, reliability and cost evaluation based on the replacement of redundant submodules of a medium-voltage MMC-based STATCOM

The adoption of redundant submodules (SMs) has become standard practice for enhancing the availability and reliability of modular multilevel converters (MMCs). Existing literature predominantly focuses on high-voltage converters, leaving a notable gap in addressing the distinct characteristics of medium-voltage MMCs. Optimizing the balance between availability and cost is crucial in designing effective power converter systems. This paper seeks to fill this void by evaluating the influence of redundant SM quantity on cost and availability, and optimizing the reaction time of the maintenance to replace failed SMs of a static synchronous compensator (STATCOM). It provides insights into the related trade-offs and facilitates informed decision-making in the design and operation of medium-voltage MMCs.