Main Tie Main Configuration

Maintenance of the tie breaker may include maintenance of the circuit breaker, the bus bar droppers and associated switchgear apparatus of the tie section. Most of the CB's are of draw out type which facilitates the isolation of the CB / downstream system as and when required.

Assuming that the tie is normally open with the two main bus systems being fed by individual feeder, if the maintenance has to be carried out on CB alone, the breaker can be racked out and appropriate maintenance program can be carried out. In this case the maintenance on the bus section associated with the tie cannot be done since both the ends are live.

For the maintenance of the associated switchgear of the tie section other than the CB like CT/PT, breaker cubicle, bus bar droppers, support insulators etc, it is strongly suggested that the maintenance be carried out only when an opportunity arises wherein it is possible to isolate both the bus sections.

However, in case of emergencies, appropriate action like isolation of the main bus section, will have to be taken depending upon your system configuration and process requirement.

I appreciate your professional opinion regarding the tie breaker. What about main-tie-tie-main? is it more advantageous than Main-Tie-Main with regards to the maintenance of tie breakers? or no need for Main-Tie-Tie-Main configuration as it perform same operation?

Opting for a main-tie-tie-main configuration just for the sake of maintenance of tie CB is a costly affair and absolutely not required. It makes the system complicated especially during system relay co-ordination studies. I don't see any significant advantages for a M-T-T-M config. Ease of maintenance of any equipment should not unnecessarily complicate a system.

As I mentioned before, in case of emergencies/breakdowns or any other unavoidable circumstances, you will have to isolate the system to carry out maintenance/breakdown jobs. A draw-out CB can very well fit into the scene wherein you may taken up the maintenance of the CB as per your requirement.

thank you for your advise. I really appreciate it.