Application of Primary Step-down Auxiliary Power System in UHV Substation

Based on the design of the auxiliary power system of Xuzhou 1 000 kV UHV substation, a primary step-down system and a secondary step-down system were presented. According to the technological and economical comparisons, the primary step-down auxiliary power system was recommended, and two wiring principle schemes for auxiliary power system were proposed, of which different from UHV demonstration engineering was recommended by reliability analysis.