Research On Communication Security Method Of Digital Substation

Substations as the important nodes of the electric power grid are responsible for voltage conversion and power distribution, whether they have accurate, safe and reliable operation is essential to the security and stability of the entire grid. Using of the LAN architecture brings the threats as the general network faces into the digital substations based on IEC61850standard, especially GOOSE messages requiring for real-time and high security, so new security requirements are proposed. To solve these problems, the achievements of this paper are as follows.MMS, SMV and GOOSE are three kinds of important messages, and the standard indicates the different requirements for their content, length, the worst-case transmission time allowed and the complexity of the security. If each message uses an encryption algorithm, which is bound to increase the burden of IEDs and affect their interoperabilities. So selecting the appropriate security algorithm to address all the different requirements is advisable. The algorithm of GCM authentication encryption is fast, no patent, and easy to implement by software and hardware, especially the three different encryption modes: authentication mode, encryption authentication mode and NULL mode can meet the security demand of substation messages. By the analysis of message format based on IEC61580and IEC62351, an extended secure message model with the combination of their advantages is designed, and three security measures of the substation messages are achieved by the definition of the reserved fields.Design the secure message transmission algorithm based on GCM of digital substation, give time cost and benefits of message secure transmission algorithms based on GCM, and prove it meets the real-time requirements. By the analysis, we conclude that for the security requirements of different messages the common message authentication encryption algorithm based on GCM by choosing different modes to achieve different secure transmission is suitable, and can improve the security of substation information and network performance.Finally, through the establishment of the digital substation based on OPNET, the influence of the VLAN and priority techniques on the network performance is studied. Simulation results show that the VLAN and priority techniques can significantly limit the scope of broadcast packets and reduce the network delay.