Many busbar automatic transfer switches (BATSs) will be triggered by N-1 analysis because of their own characteristics of a regional power grid. In the traditional method

a specific failure is simulated first

then the topology analysis is made and finally the topology analysis considering BATS operation is made. The whole process involves frequent switch operation

so a great deal of topology calculation is needed. Two real-time N-1 calculation methods considering BATS are proposed based on the characteristics of the regional power grid. In these methods

BATS operation is simulated by the load transfer method in the flow check process by means of power supply path search or pre-building the mapping relation between N-1 fault and actuating BATS. As the method does not have to change the topology information of the power grid

it can significantly reduce calculating time. Field operation shows that the proposed method is feasible and better able to perform N-1 analysis for the power grid.