Ring Main System

 Ring Main System

In this system, the primaries of distribution transformers form a loop. 

The loop circuit starts from the substation bus-bars, makes a loop through the area to be served and returns to the substation. 

The single line diagram of ring main system is shown in Fig.

Ring Main System  Advantages

There are less voltage fluctuations at consumer's terminals.

The system is very reliable as each distributor is fed via two feeders. 

In the event of fault on any section of the feeder, the continuity of supply is maintained.

For example, suppose that fault occurs at any section of the feeder. 

Then the faulted section the feeder can be isolated for repairs and at the same time continuity of supply is maintained to all the consumers via the other feeder.