We propose the operation mode as:1. Only one incoming circuit breaker is allowed to be closed between incoming #1 and incoming #2.2. Only one incoming circuit breaker is allowed to be closed between incoming #3 and incoming #4.3. The incoming #1, incoming #3, Bus-Tie, only two of the three are allowed to be closed in any case. 4. When two sections of Bus are powered by incoming #2 and incoming #4, and synchronism check is OK, then the Bus-Tie is allowed to be closed.5. When two sections of Bus are not both powered by incoming #2, incoming #4, the Bus-Tie is not allowed to be closed.6. Two sections of Bus are both powered, when one section of Bus is out of power, the Bus-Tie will be closed by Spare Power Source Automatic Device.