Abstract:DC offset in current of circuit breaker is non-ignorable during transmission lines energizing with shunt reactors, especially when transmission lines have a high level of compensation or overcompensated. In most cases, there is a long time without any zero-crossing point of current when energizing, and it will cause arc extinction problem for the circuit breaker if there is a trip operation. Based on the principle of DC offset generation and the failure risks of circuit breakers caused by DC offset, conventional measures to suppress DC offset are discussed,which include addtion of closing resistors for the circuit breaker, reducing compensation degree and controlled closing. A method which combine the controlled closing technology and dynamic delay closing for each phase are proposed, then the risk can be successfully eliminated during transmission lines energizing. The effectiveness of above method is validated by RTDS simulation and field test on several transmission lines.