LV generator protection - engineering site - Schneider Electric

2.2. Transfer deviceIt is interesting to make the source transfer (or source switching) device usingstandard switchgear, adding specific features. Thus the devices will be:b withdrawable for easier maintenanceb electrically and mechanically lockedFor implementation, the distribution architecture and transfer sequence must bestudied.2.2.1. Layout of feedersAs a rule it is not necessary to back up the entire installation. An economicmeasure is to size the Generator Set for supply of the priority feeders only.For example: sizing the Generator Set at 700 kW for a LV distribution of 2000 kVA(only one third of feeders are considered priority).Transfer of load supply to the replacement source can be considered in 2 ways.Transfer with load-shedding of non-priority loadsPriority and non-priority loads are not specifically grouped: management (loadshedding)of loads must be performed by a dedicated automation device or relay.This configuration type requires a management auxiliary but is easier to modify orupgrade.E79353EMVLVMain LV boardNCGSLoadsheddingNon-priorityPriorityNC: normally closed.NO: normally open.Figure 8: Management of priorities by load-shedding.13