Design of 500kV Hybrid HVDC Circuit Breaker Control and Protection System

In terms of timeliness and reliability, the performance requirements of the control and protection system of the Zhangbei 500kV hybrid high-voltage DC circuit breaker is put forward. To meet these performance requirements, the control and protection system suitable for 500kV hybrid high voltage DC circuit breakers is designed. The topology and working principle of Zhangbei hybrid highvoltage DC circuit breaker is analyzed. The basic circuit breaker control strategy and body protection configuration are studied. The hardware architecture and software flow of the control and protection system are designed. Furthermore, a series of designs such as high-performance and anti-electromagnetic interference of the board have been carried out. The redundancy design of the system is carried out from four aspects: control system, protection system, monitoring system and power supply. Finally, combined with the Zhangbei flexible DC power grid test demonstration project, the hybrid high-voltage DC circuit breaker control and protection system is verified by the current breaking test and the reclosing test. The test results show that the control cycle is
$25\mu\mathrm{s}$
and a protection action delay is less than
$350\mu\mathrm{s}$
. The system can reliably complete the breaking of the circuit breaker within 2.7ms, the impact of fault current on converter valves and other equipment and systems is reduced. The performance requirements of 500kV hybrid high-voltage DC circuit breakers in Zhangbei project are met.