With the development of the industrial age, electric power has become the main power resource in the development of human history. So as to achieve the purpose of reducing production costs and increasing economic benefits. Substation is an important part of power system, which directly affects the safety and economic operation of the whole power system. At present, for household middle and low voltage substations of 110kv and below, the main wiring shall be multi-single bus wiring to ensure safety and reliability. In addition, reasonable selection of various primary equipment can also improve the safety factor and economy of the substation.