The key technology of distribution transformer and static var compensator integration system

Towards the reactive compensation feature of distribution network and integral substation, this paper proposed an integration structure of distribution transformer and STATCOM (DT-STATCOM). It use the surplus capacity of transformer to compensate the reactive power; by setting the connect voltage flexible, it extended the switching devices selection; the integration structure reduce the volume and cost of compensation device. Based on the structure of DT-STATCOM, this paper proposed two novel reactive current detection method across the transformer´s ports. Then the paper designed the decision control system using multi-lateral information. Simulation result showed that, the DT-STATCOM system had significant effect on dynamic reactive power compensation, transformer voltage support and imbalance inhibition.