Abstract:Based on national standard about the design of 35kV substation, manuals, standards and the subject for 35kV terminal step-down transformer substation electrical primary research and design. 35kV bus side with single busbar connection and take a way back into the line, the main transformer adopts two SZ9-8000/35 on-load voltage regulating transformer; 10kV side with simple single busbar of busbar and eight back line; 10kV main feed line the ZN28-12 type vacuum circuit breaker, wire controller circuit breaker and protection, is employed as control and protection, this topic research combined with the requirements of the new era, and adopt new technologies and energy-saving design principles, to further improve the substation electrical system optimization design, have certain reference significance to facilitate the future substation project design, improve the work efficiency.