The 35 KV substations a system designed for the metallurgical factory system mines, smelting and rolling mill industry producing all kinds of electrical equipment and accessories business, its high concentration of production machinery, equipment greater consumption of electricity demand higher, Power interruption will cause decline in production and product quality, bring greater economic losses. To avoid accidents, ensure the smooth progress of production, we must use such as: Fang Chudian, overload, over-current protection and mine and a series of technical measures and corresponding management system to ensure the security of electricity supply. In addition to the reliability of electricity supply and meet the security requirements, should also meet the system simple, flexible operation, easy to operate, construction, investment and operation and maintenance costs low, conditions and the quality of power supply can be guaranteed. After calculation, access to power supply design document and Design Manual, identify relevant factors and parameters, the final choice of a 4000 kV • A main transformer and the corresponding equipment. Therefore, this issue could become the general design of 35 KV substations a system design samples.
