Voltage-sharing Design and Test of 500 kV Fast Isolation Switch with Multi-break

The breaking speed and stability of fast disconnector, which is one of the key components of hybrid direct current(DC) circuit breaker, are directly related to the performance of whole circuit breaker. Up to now, in order to meet the requirements of fast isolation, the multi-break scheme is generally adopted for an isolator for high voltage circuit breaker, the isolator has 8~12 breaks, and its structure is complex, which proposes higher requirements for multi-break voltage sharing. Consequently, we analyzed the requirements of fast disconnector for 500 kV hybrid DC circuit breaker. Combining with the structure layout of 10-break disconnector, we proposed a method of voltage sharing based on field-circuit coupling, which optimizes the voltage sharing of the fast isolation switch and completes the relevant test verification. It improves the performance disconnector, decreases the number of breaks and improves the reliability of the whole machine. © 2019, High Voltage Engineering Editorial Department of CEPRI. All right reserved.