Study On10kV Distriibution Transformers And Prefabricated Substations Boosting To20kV

10kV voltage level played an important role in medium-voltage distribution for a long period of time. However, load density in urban area, especially in urban centers, is increasing with the rapid development of social and economic. Due to the limited supply capacity of substations and distribution lines, we have to increase the substation density and quantity of10kV lines to meet the increasing load demand. On the other hand, it is more and more difficult to get substation land and line corridors in urban areas, so it is very necessary to boost the medium-voltage distribution from10kV to20kV.Transformers and prefabricated substations are important parts of lOkV distribution equipments, which exist in medium voltage distribution network with a large quantity So reasonable modification and utilization of10kV transformers and prefabricated substations will significantly reduce the cost of the boost transformation and ensure the smooth implementation of the project.In this paper, the study is from the point of view of the design of distribution transformer, calculating the core, low-voltage winding and high voltage winding parameters of dry-type transformer and oil-filled transformer to determine the boost transformation of technical feasibility. What’s more, this paper determines the optimal rehabilitation programs by economic analysis, that compares transformation cost and replacement cost of new capacity20kV transformer program, for technically feasible solutions. And the conclusions can be references for lOkV distribution network boost renovation project.The results show that,10kV dry-type transformers boosting with significant capacity reduce has no economic advantage, so10kV dry-type transformers should be replaced by20kV ones. In addition, most oil-filled transformers can be boosted to20kV ones without capacity reduce, and the cost is35%-45%of new20kV oil-filled transformer price. Furthermore, there is transformation feasibility for European box-type substations, and American box-type substations should be replaced by20kV ones.