The Technical Study Of 20kV Voltage For Distribution Network

With the rapid and stable development of the national economy and the improvement of city load density, 20kV voltage have become the urgent needs in some distribution network for cities and development zones, and in some areas it have been put into practical operation. So far, there are still some key technical issues which relate to the planning and application of 20kV network need to study on: 1. the economic capacity of the substation and best power supply radius in different load density; 2. option of 20kV power grid connection mode which adapt to the development of the region's load; 3. the application of 110/20kV and 220/20kV high-capacity transformers; 4. the research of new low-voltage power supply mode.In this paper, 110/20kV substation economic capacity and the optimal power supply algorithm radius have been established through the optimization theory and large-capacity transformer's application conditions and the range of load density have been analysised first. And then to consider the development of the region's load, some of the grid connections of 20kV power distribution have been studied and a selection method for 20kV power grid model has been setted, which based on fuzzy theory and TOPSIS algorithm. At the same time, the feasibility and connection model to use single-phase transformer for power supply in low-voltage side of 20kV network have been studied in this article.In this paper, Wuxi Taihu Lake Area has been taked for example. Through the calculation and analysis, the feasibility and correctness of theories above have been proofed.