The protection strategy analysis of the last circuit breaker in the 1 + 1/2 operation mode

This paper makes a brief introduction to the protection logic of the last circuit breaker of arrester type. Afterwards, two novel protection strategies for the last circuit breaker of arrester type are proposed aiming at solving the problem that the protection of the arrester type last circuit breaker at the inverter side of the high-end converter cannot function properly when it´s out of operation. Based on the simulation model of the ±800 kV Yunnan-Guangdong UHV AC-DC hybrid systems, a simulation verification is carried out on the PSCAD / EMTDC platform, and the result indicates the correctness of the proposed two novel protection strategies for the arrester type last circuit breaker.