换流站传递特性及其对交直流电网保护影响

China has built the world's largest high voltage hybrid AC/DC power grid. The key component of the hybrid AC/DC system is the converter connecting the AC and DC power grids. The converter regulator is non-linear and time-varying with complex interactions between the AC and DC grids. For relay protection research, it is important to study the relationship of the electric quantities between both sides of the converter and the coordination of the protection configured in the AC/DC system. This paper introduces a mathematical model of the converter station transmission characteristics and its fault analysis limitations. Then, protection methods for the AC and DC systems are evaluated based on the transmission characteristics. A commutation failure on the DC side can be transmitted to the AC side which will influence the adaptability of the AC system protection. In addition, an AC system disturbance can be transmitted to the DC system, which will affect the DC system protection. Solutions are given to correct these incorrect AC/DC protection responses. Finally, additional research ideas are given for fault analyses and protection principles based on the converter transmission characteristics.