A Study on Transient Recovery Voltage of UHV Circuit Breakers

The authors investigate the transient requirements of 1100kV AC circuit breakers mainly for China's Jin-Nan-Jing UHV pilot project.This research item includes two parts:(A) The transient recovery voltages (TRV) after circuit breakers interrupt the short-circuit currents or the current in out of phase condition:(B) The time constant of DC component of short-circuit currents and zero offset of current. Based on these results,the suggestion on transient requirements of 1100kV AC circuit breakers is presented.As the fast part of the research item,this paper focuses on the transient recovery voltages of the UHV circuit breakers after the short circuit current is broken or the gird is sectionalized due to fall-out of synchronism.According to the results in the UHV pilot project, it is anticipated that without using opening resistor,the TRV peak values and the rise rates of circuit breaker in the UHV power system fall within the allowed ranges prescribed in either the IEC circuit breaker standard extension or Chinese test condition for 1100 kV circuit breakers.