The Study Of Key Issues In Standardization Design Specification And Its Applications In Digital Substation Design

Due to the lack of unified design specifications, there are some differences between digital relay protections from different manufacturers, which makes the site maintenance and operation become more difficult, and even become unsafe. It is necessary to formulate unified relay protection standardized design specification. With the wide application of digital substation, it is required that the high reliability of the process layer device which directly related to relay protection equipments such as the electronic transformer, merge unit, intelligent terminals, network structure and so on. The study of key issues in standardization design specification and its applications in digital substation design is of great practical significance. Firstly, we discuss the reason of breaker failure protections mal-operation, we proposed a reliable criterion of breaker failure protection, and practice shows that the method is effective. Secondly the trip of operating bus bar by bus coupler charging dead zone protection mal-operation is studied, and the reasonable protection logic is put forward. This paper also puts forward the optimized protection scheme for transformers. At last, the key equipment and secondary system design in digital substation have been described.