In order to solve the problem of network redundancy in substation automation systems, a new network redundancy device (double network redundant interface box and double network redundant interface card) is proposed to implement. The devices of the substation internal protection and control are connected to the PRP/HSR network which conform to IEC 62439-3 specification through the redundancy connection equipment. By using the hardware architecture of FPGA+CPU, the Ethernet communication control MAC module, PRP/HSR module, storage control module and multiple message forwarding control module are designed by using the Ethernet communication control module, and the redundant processing of Ethernet message in the substation system is completed. The test proves that the redundant equipment developed meets the requirements of the power system protection device for quick action, and has good practicability in smart substation automation systems. This work is supported by Science and Technology Project of State Grid Corporation of China (No. JBB17201500229) “Research on Smart Substation Network High Reliability Redundancy and Relay Protection Network Communication Routine Auto-generation Technique”.