Main　electrical　wiring　is　a　circuit　diagram　which　is　used　to　meet　the　production　needs　of　the　power　transmission　and　distribution　and　in　accordance　with　a　certain　manner　and　order　and　use　provisions　of　graphic　symbols　and　text　code　to　connect　once　equipment　(generator　transformer　switching　equipment,etc.)　together.　It　reflects　the　basic　structure　and　function　of　traction　substations　and　substation　(power　generation).　In　operation,　it　shows　the　primary　operating　mode　of　substation　(power　generation)　and　high　voltage　grid　connection　and　associated　feeder　devices　and　become　the　basis　of　controlling　and　scheduling　apparatus.　This　paper　analyzes　single-bus　connection　from　the　reliability,　flexibility　and　economy　point　of　view,　then　outlined　the　typical　single-bus　wiring　switching　operation　principles　and　methods.　©　(2014)　Trans　Tech　Publications,　Switzerland.