With the development of power supply technology, kinds of sophisticated techniques, components and equipment were been widely used. Paper mill has complex technological process and many large-scale equipment with larger power load. Strong-continuity manufacture and highly concentrated manufacturing machine are the characteristic of paper manufacturer. It demands higher quality and stability of electricity. According to relevant national standards and norms, calculations of the whole plant load, compensation of power factor, choice of the total step-down substation’s transformer and workshop substation, main wiring design of the papermaking factories’ substation, short-circuit current calculate, selected of primary equipment, program design with relay protection, setting parameters for the distribution circuit design., lightning protection and grounding options were designed. The result of design shows the detailed calculation process, supply and distribution system plan can give a medium-sized enterprise which change of the power supply system, to provide the reference.
Keywords：primary and secondly design, power supply system design, 35kV power supply system, paper mill
