Types of Distribution System


There are following types of distribution system.

  • Radial system
  • Ring main system
  • Interconnected system

Radial distribution system

  • Figure shows radial distribution system. One feeder PQ is radiate out from the substation. 
  • It feeds distributor from one end only. 
  • The distributor is fed at point A and terminates at point D. 
  • It means that the load is given at first consumer A and last consumer D.
  • Obviously, the last consumer gets less voltage due to voltage drop in the distributor.



  • Simple distribution system
  • Less initial cost


  • When a fault occurs on distributor, power supply is completely interrupted at fault point to all the consumers
  • Consumer at far end gets reduced voltage
  • If the distributor is extended for future load, the voltage drops increase

Ring distribution system

  • It is a distributor in the closed loop and fed at one or more point. 
  • Such a distributor starts from one point and makes loop through area and finally returns to the same point. 
  • The distributor can be considered as series of open distributors fed at both ends.
  • The ring distributor feeding from one point is shown in the figure. 
  • Here P is feeding point and PQRSTUVWP forms closed loop for feeder. The tapings for the distributor is taken from point R, T and V respectively. 
  • The distributors A, B and C are shown in the figure. 
  • It is equivalent to straight distributor fed at both ends with equal voltage for the calculation purpose.



  • Less copper requires than the radial system
  • Less fluctuation of voltage at consumer’s end
  • Reliability increases, if the fault occurs at point, the power supply are maintained from other point.

Interconnected distribution system

  • When the ring feeder is energized through two or more than two generators / substations, it is called as interconnected system. 
  • Figure shows two substations S1 and S2 which feeds feeder PQRSTUVWP. 
  • If there is fault between feeders RS, the feeder Q and R receives power through substation S1 and feeder S receiver power through substation S2.



  • Service reliability increases
  • Good voltage regulation is achievable
  • Peak load can be fed from the other substation and this will reduces the reserve generating capacity

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