Ring Main Distribution System

Another system of distribution which eliminates the disadvantages of the radial system is used in practice called ring main distribution system.

       In such system, the feeders covers the whole area of supply in the ring fashion and finally terminates at the substation from where it is started. The feeder is in closed loop from and looks like a ring hence the name given to the system as ring main system. This is shown in the Fig. 1.

       The feeder in the ring fashion is divided into number of sections as AB, BC, CD, DE and EA. The various distributors are connected at A, B, C, D and E. Each distributor is supplied by the two feeders and hence the design is similar to the two feeders in parallel on different paths. Hence if there is any fault on any part of the feeder, still the consumers will keep on getting the continuous supply. For example, if the fault occurs at point P in the section AB of the feeder can be isolated and repaired. The feeder can be fed at one or more feeding points. Thus the disadvantages of radial system are eliminated in this system. The great saving in copper is another major advantage of the ring main system.