Research On The Security Evaluation Method Of SCADA Communication Links Based On Bayesian Network

With the rapid development of communication technology, the smart grid hasbecome a development trend of the power system. In power systems, The SCADAcommunication system is a major platform for scheduling and monitoring. The securityof communication links, which connect the control center and substations, has become ahot topic to researchers in the power industry. Relative public communication network,security requirements of the power communication network are unique. So the method ofsecurity evaluation on power communication network can’t be copied from the of publiccommunications network. A special security evaluation model should be found for thepower communication system.The security not only has an associated feature, but also should be predictable. Atfirst, the physical structure and security demands of SCADA communication system areanalyzed. Then, a Bayesian model, which is based on the relationship among threats,vulnerabilities, countermeasures and security events, is built after analyzingvulnerabilities and threats of power communication equipments. This model can helpdecision makers choose some effective countermeasures, and also can describe theparticularity of electric power communication network. Depending on Threats,vulnerabilities and defensive measures of the PCM equipment, the SDH equipment andthe optical fiber, security evaluation model is built. For illustration, one piece ofcommunication link is selected from some substations. Each node in this link, such asPCM equipments, SDH equipments and optical fiber, is evaluated. The securities ofphysical and information are fully considered in his model. So the result, which can helpdecision maker to choose some effective counter-measures, is objective.After theanalyzing of security evaluation results, it is proved that the security evaluation model ofSCADA communication systems has practical value and directive significance.