By analyzed the case of unsuccessful reclosing situation of a 500 kV circuit breaker

the reasons of the fault was due to the improper value of the circuit breaker’s low pressure interlocking settings.When the temperature of external environment sudden droped

low pressure interlocking relay action

leading to the unsuccessful reclosing of the circuit breaker.The paper developed a corresponding coping strategies according to the reason

that was adjusting the value of low pressure interlocking settings to the appropriate ones

ensure that the circuit breaker could operate normally and action correctly to adapt to different operating conditions.And protect the operation of the equipment and grid safely and stablly.The strategies achieved good results

for preventing and dealing with similar fault it was of a certain significance.