Reliability Analysis of Multi-terminal Blocking-type MMC Flexible DC System

Reliability and economy are the key to realize the large-scale and intensive development of offshore wind power. The hybrid converter valve based on improved series double sub-modules has better economy in scenarios such as large-scale offshore wind power grid connection. In this paper, the technical economy of hybrid MMC converter valve based on improved series double sub-module and half-bridge sub-module is analyzed. Compared with other MMC converter valves with DC fault clearing ability, the hybrid MMC converter valve based on improved series double sub-modules and half-bridge sub-modules is more economical, and has stronger DC fault clearing ability, and the system has high reliability.