Abstract: One of the important issues in a substation automation system is performance of the communication buses consist of station bus and process bus. The station bus provides communication between station level devices and bay level devices and the process bus provides communication between bay level devices and primary equipment. In substation automation system, the appropriate operation of protection, control and monitoring systems depends on communication network accuracy. The communication network architecture is based on the required data, reliability and commissioning requirements during the installation of the SAS (Substation Automation System). It is clear that the reliability and security of the communication networks are different respect to importance of the substation. Therefore, the significance of the substation can be used to determine the communication network and inside the substation bus configuration. In this study, a new approach is proposed to determine the significance level of substation based on 7 factors and then the architecture of communication buses has been configured.