On the basis of analysing the structure of medium-voltage auxiliary power system in Waigaoqiao Power Plant no.2

an optimization scheme

steps of its implementation

and the effectiveness after optimization have been worked out.After optimization of the structure concerning medium-voltage auxiliary power system

the motors' load of total power 2 000 kW in the medium-voltage auxiliary power system has shifted onto 3 kV bus of auxiliary power

the auxiliary transformer equipments of total capacity 32 000 kVA being shifted onto 10 kV bus of the auxiliary power

the auxiliary transformer equipments of total capacity 25 200 kVA being composed into two auxiliary sections of 10 kVA respectively

being supplied from high-voltage auxiliary transformer during the time of normal operation.The advantage of original design is reserved in optimization

electricity puchassed from outside being decreased by a big margin

enhancing the economic efficiency in operation of units.