Advances to megawatt scale demonstrations of high speed fault clearing and power restoration in breakerless MVDC shipboard power systems

The studies shown in this paper extend the work conducted previously for the megawatt scale demonstration of high speed fault clearing and power restoration in MVDC systems using modular multi-level converters (MMC) and fast disconnect switch. Enhancements were made to the MMC controllers to improve the performance and response times for certain trigger events during fault isolation and re-energization of MVDC systems. The time required for process of fault management, i.e., fault detection, location, isolation and re-energization has been reduced from previously achieved time of 80 ms to less than 25 ms. Moreover, the dynamic performance of the converters has been improved substantially. This work paves the way towards a breaker less architecture with fault clearing times approaching one 60 Hz cycle.