IEC 61850 based substation automation systems simplify the design, installation and maintenance with significantly reduced cost. Its real-time, security and reliability are of concern and are vital important to the industry. This paper presents the development and application of an established platform for evaluating process bus applications. The evaluation platform consists of a number of GOOSE, SMV TCP/IP and impairment generators, a GPS clock, a protocol analyzer and a test set. An example of a given architecture for sampled values streams and GOOSE transmission over the network testing and the related test results are presented in the paper. Various types of background traffic over different network architectures and their impact on the process bus reliability are discussed.