Impact of Different Protection Outlet Schemes on the Body Equipment of Large Capacity Power Flow Control Device

The large capacity power flow control device is able to quickly and flexibly control the power flow of the line, improve the uneven power flow of grid and realize real-time control and dynamic compensation of the AC line. The protection system is a guarantee to realize system dynamic performance and safety and reliability of the system operation. The Unified Power Flow Controller (UPFC) and the Static Synchronous Series Compensator (SSSC) are the most typical devices. This paper mainly studies the influence of two kinds of protection outlet schemes on the body equipment of the UPFC based on Modular Multi-level Converter (MMC). According to parameters of the demonstration project and RTDS real-time digital simulation experiments, focus on analyzing the effect on DC voltage, sub-module capacitor voltage and thyristor bypass switch (TBS) with the three-phase short-circuit fault of the series valve side AC bus respectively.