Configuration Principle of Last Breaker Trip Equipment in Inverter Station of HVDC

The last breaker trip equipment is a very important control device in inverter station of HVDC system, whose main function is to prevent overvoltage at the AC side of the converter station and other parts. The overvoltage caused by sudden trip-out of all AC loads in the inverter station while the DC system still being in operation, will lead to damage of the AC and DC equipments. Taking the Lingbao back-to-back HVDC project for example, which is the first fully home-produced HVDC project in China, the last breaker trip equipment is analyzed in detail. Learning from the practical design and commissioning experiences in this project, the control functions of last breaker trip equipment are optimized, and the design principle and commissioning experiences are summarized. These experiences can be referred to other HVDC projects and are also helpful for improving the design, commissioning and operation level of HVDC projects in China.