The action behavior of the protection is analyzed when current transformer (CT) is installed in different positions in case that the fault point is between the circuit breaker and the CT. If the action behavior could not remove the fault reliably,the range of outage would be extended. At the same time, in the case of a dead-zone fault, the action logics of the failure protection of circuit breaker and the dead-zone protection are analyzed. The current situation of the nstallation locations of CT of 220 kV circuit breaker and above in Sichuan power grid is summarized, and based on the existing researches, the suggestions are proposed that the CT should be arranged on both sides of circuit breaker strictly in accordance with the requirements of anti accident measures.