The Research Of Economy Capacity Medium Voltage Distribution Transformer

Nowadays, there are various models during choosing medium voltage distribution transformers in power network planning under the technical principles, in which optimal economic capacity of transformer directed to different areas is fewly considered. During the process of network planning, the capacity of transformers is simply set as the final load level without thinking running economy. It is quite necessary to give consideration to the both sides, running economy and final load level.The paper is focus on the research of 10kV distribution transformer's economic capacity in Shanghai area, which is helpful to the network planners. One section is choosen to collect load data of resident for analyzing. Compared with some developed country's developing process of power network and load, the paper brings up the improved Total Owning Cost(TOC)algorithm, which calculates the cost of investment, maintaining and wastage to the income from electricity sales. It is an more objective reflection of transformer economy compared with only considering investment and wastage. By the algorithm, the economic capacity of distribution transformer could be decided not only in distant but also in transitional years. Through the research, the paper suggests 600KVA distribution transformer should be used in final years and the load rate should be controlled as 65%. According to the increasing of power load, 315KVA,500KVA and 600KVA distribution transformer could be in function, the replacement cycle is 20 years, and the load rate is also 65%.