Abstract
Power of modern industrial production of major energy and power, is to achieve an important material basis for production automation. Substation is the place on the electricity power system voltage and current to change, focus and allocation. With the development of industrial electrical automation technology, the rapid growth of electricity consumption in factories, power quality, power reliability, and technical and economic indicators increasingly higher demands. Power is easy to convert from other forms of energy from, but also easily converted to other forms of energy to supply with; power transmission and distribution is simple and economic, and easy to control, regulation and measurement, is conducive to automation of the production process. The 10KV substation of a factory plant electrical system design, including assembly workshop, electroplating shop, welding shop, machine shop, heat treatment shop, maintenance shop, boiler room, test stations, warehouses, offices. The content of the main design load of the whole plant, high pressure into the line selection, select the number of transformers and substation plant capacity, etc.. Through the design of the original data, all plant load calculation, select the appropriate number and capacity of main transformers to determine the specific power supply system. Then the system of its primary short-circuit calculations and the corresponding high and low voltage equipment selection and validation, selection and validation of high voltage lines, and finally a simple set of instructions to relay. Combined with basic knowledge of textbooks, according to China by the operation of distribution and a variety of transformers, switchgears, circuit and other electrical equipment standards for specific quantitative selection of electrical equipment, eventually reached a specific step-down on the total plant substation power system plan. Key words electric load， short-circuit ，current transforme，r substation
