The current smart substation process layer adopts dual-network architecture and IED processor processes dual-network data simultaneously, which causes the problem of high processor load. SV uses the mode of directly connected through optical fiber transmission, in which exists complex wiring, multi port of IED equipment, high cost, high heating of equipment, difficulties in information sharing, and the issues that links can not be monitored, etc. At the same time, GOOSE adopts network transmission mode, the process layer network and optical fiber connection mode coexist, so the structure is not clear. The process network of smart substation of HSR (High Reliablity Seamless Redundant Protocol) and PRP (Parallel Redundant Protocol) is studied, and the delay accumulation technology of HSR and PRP is studied and tested on the basis of the network. It provides a solid theoretical analysis and test result reference data for the future popularization and application of smart substation in China. This work is supported by Science and Technology Project of China Southern Power Grid (No. ZDKJQQ00000016).