When it is the failure in this range, ANN1 (sub-system) protecting Agent in itself side acts and meanwhile receives the trip command from organize of Agent. The trip time delay of breaker is the summation of action time of protecting Agent and organizing Agent as well as the time of transmitting signal. ANN1(sub-system) and ANN2(sub-system 2) protecting Agent in opposite side act and breaker instantly trips whose time delay is the time of protecting Agent itself and acting.