Security risk assessment and weaknesses identification of the substation automation system

Due to the popularity of intelligent electronic device and digital information transmission in intelligent substation, the security issues of the SAS have become increasingly prominent, it is necessary to carry out security risk assessment for the SAS. This paper proposed a methodology for the security risk assessment of the SAS, the function-based model (FBM) was proposed according to IEC 61850, by which the SAS could be decomposed into functions. Secondly, a method for calculating the function failure probability was presented, referring to information security risk assessment norms, function value was defined to measure the loss of function failure. Based on AHP (analytic hierarchy process, AHP), the transmission weights of function risk were calculated, to integrate function risk into system risk Based on the sensitivity analysis, the assessment and ranking for different parts of SAS are completed, and the weaknesses of SAS are found. Finally, Taking Tl-1 substation SAS system as an example, the feasibility and applicability of the proposed method was verified.