Analysis of action process of ZnO arrester in HVDC vacuum circuit breakers

Due to the absence of a natural current zero crossing in breaking process of a DC system, DC breakers have to dissipate the large amount of residual energy which is stored in the inductance in the system. ZnO arresters are used for switching over-voltage preventing and residual energy absorption. A dynamic simulated model of HVDC vacuum circuit breaker (VCB) with forced current zero based on PSCAD is set up. Action process of ZnO arrester with microsecond breaking process is analyzed first. The option and installment of ZnO arrester have been considered critically and the criterion of the ZnO arrester option is proposed. Simulations demonstrate the validness of the theoretical analysis and verify the effectiveness of the option and installment of ZnO arrester. At last, the relevant issues about ZnO arrester remaining to be studied in the HVDC vacuum circuit breakers are proposed.