Abstract: Aiming at the problem that the original voltage parallel design scheme does not meet the protection and automatic device sampling in the comprehensive self-transformation of the 110 kV system configuration of the three-section bus and two-bus voltage transformer in the 110 kV system of the expanded inner bridge connection substation, a new wiring disposal scheme is provided. The difference between the original and current design wiring schemes and the matters needing attention in the later operation and maintenance are analyzed and explained to prevent the abnormal events that the bus voltage cannot be collected and affect the protection and automatic device during the operation and maintenance operation. It provides reference for the later operation and maintenance personnel in the voltage parallel device transformation process.