Functions and implementation of substation-area backup protection in smart substation

Substation-area protection is the key aspect of new generation protection system with a layered structure in smart substation. This paper describes the concept, coverage and functions of substation-area protection and the coordination with other subsystems. Then an idea of implementing full-featured applications of substation-area protection gradually has been proposed. According to the practical functions, a series of protection modules have been designed subsequently, which involve unit redundancy protection, optimized substation-area backup protection and substation-area automatic controller. To meet the requirements mentioned above, a dedicated hardware platform has been proposed, including main processor module, FPGA (field programmable gate array) data processing module and a data communication module between boards. Finally, a prototype of substation-area protection adopting the proposed design has been realized. The performance of the prototype is evaluated through static experiments and RTDS (Real Time Digital Simulator) simulation of a typical 110kV substation. The test results show that the specialized indexes of the prototype have fully reached engineering requirements.