BASIC OF DISTRIBUTION SYSTEM


FEEDERS:-

             A conductor which connects the substation to the area where power is to be distributed.

Distributors:-
A conductor from which tapping are taken for supply to the consumers.


  • Voltage variations + 6% of rated value at consumer terminals.
Service Mains:- A small cables which connects the distributor to the consumer terminals.



Distribution System Scheme:- 


Radial System:-


Separate feeders radiate in a single sub-stations.
Feed the distributor at one end only.
Radial system is employed only when power id generated at low voltage and the substation is located at the center of the load. 

Disadvantage of radial system:- 

  • The end of the distributor nearest to the feeling point will be heavily loaded.
  • Load shading in many times.
  • When load on distributor changes , there are serial voltage fluctuations. 
Due to above disadvantages, radial system used for short distance only.


Ring Main system:- 


  • In this system primaries of distributor transformers from a loop by several power plants.
  • There are less voltage fluctuations.
  • There are less load shadings.
  • This system is very reliable, continuity of supply is maintained.
  • If fault occurs in any point of feeder, these section of the feeder can be isolated for feeders can be isolated for repairs.

Interconnected System:-


When the feeder rings is energized by two or more than two station(generating) or substations. It is called Interconnected system.


Advantages of Interconnected System:-

  • It increases the service reliability.
  •  Any area fed from one generating station during peak load hours can be fed from other generating station.
  • This reduces Reserve power capacity and increase efficiency of the system.