Main-Tie-Tie-Main (M-T-T-M) Configuration - Auto Transfer

[Charz]

If two bus ties are connected in series and auto-transfer operations are required, what is your preferred method for performing the transfer?

1. Keep Bus Tie A normally open and Bus Tie B normally closed; Consider there is only one bus tie which is A.
2. Configure Bus Tie A as the “Master” and Bus Tie B as the “Slave,” so that Bus Tie B always mirrors the Master’s status.

 

[jim dungar]

Option 1.

I don't like switching more breakers than necessary.

 

[ron]

We leave 1 closed and the other is automated.

The "extra" tie is there for safety and not worth automating.

 

[jim dungar]

The "extra" tie is there for safety and not worth automating.

Safety during maintenance. With two open ties you can have total deenergized breakers and cells. With only one tie, that cell is always partly live.