Digital Substation Information Security And Network Reliability Study

With development of electronics, software and communication technology, substation automation technology had made great progress. Based on substation automation, intelligent switch,non-conventional instrument transformer,primary equipment state monitoring online and substation operation training simulator technology are becoming more and more mature; and high-speed computer network in real-time system had developed; IEC61850 standard had enacted, which make the digital substations' construction possible. Nowadays, the study on Digital substation has achieved great success, but there remain some questions that are widespread concerned about, such as information security and network reliability. The communication network system based on IEC61850 is consistent with the upper structure, which will greatly improve equipment interoperability and interchangeability in the substation. However, the open and standard of the agreement brought an important issue: the second system security. A large number of intelligent electronic devices will be applied in digital substation, and there is a lot of information about operating,state and control to transfer. The network communication system that is responsible for the transmission of the information will be the key of digital substation. And network reliability is directly related to digital substation's good performance.This paper analysed the key technologies in digital substation: non-conventional transformer, intelligent devices, IEC 61850, Internet technologies and so on. Substation information models are proposed according to IEC 61850. The various technologies that protect digital substation information against attack are analysed, such as encryption, digital signatures, virtual network, multi-agent, firewall, etc. Based on trusted platform module, substation remote communication structure is designed. As for the issue of network reliability, fault tree and Bayesian technology are studied. And Bayesian network based on fault tree is applied in reliability analysis of digital substation. It is proved to be feasible and valid via an example.