The SCL language for substation configuration description is standardized for the exchange of configuration information between different manufacturers. Based on an analysis of the SCL object model， SCL based graphical topology display for substation， and harmonization of SCL and CIM semantic models， a software architecture of improved SCL system configuration tool has been designed which includes the import and export modules for SCL configuration files， graphics operation function module， generation module for SCL object model， export module for SVG files and export module for CIM/XML files. A line bay and IED in a 110 kV substation are described and configured with SCL and thus the configuration management of the substation and IED can be easily realized by means of the SCL system configurator.