Substation configuration description(SCD)file is important data for equipment operation

routine operation and maintenance

project management in smart substation. In view of the engineering application problems brought about by the high degree of coupling in the SCD model

the necessity and urgency of the decoupling technology about the SCD model is expounded. For the smart substation expansion project

the scheme of SCD bay physical decoupling is analyzed

and the bay modeling method based on the system specification description(SSD)model is put forward

which makes secondary devices grouped into the bay. The SCD model is decomposed into a number of bay files mainly by physical decoupling. And the unrelated bay

the correlation bay and the new bay are defined for the smart substation expansion project scenario. By means of physical isolation

automatic analysis of the relationship between the bay based on the SSD model

hierarchical signature comparison configuration modification

the unrelated bay is isolated and modification errors are avoided. The area of the configuration

debugging and testing

etc

is reduced for the smart substation expansion project. For engineering application requirements

the configuration process of SCD bay decoupling is given for the smart substation expansion project. Current main problems demanding prompt solu-tion for SCD bay decoupling are analyzed. This work is supported by State Grid Corporation of China.