Security risk assessment of IEC61850-based substation automation system

Substation automation system (SAS) based on IEC61850 is the direction of SAS, whose security risk assessment is meaningful. The function-based model (FBM) was proposed, by which SAS could be decomposed into functions and described in mathematical language, and the security risk of SAS is divided into system and function risk. A method calculating function failure probability is presented, logical connection, logical node and function value are defined to measure function failure consequence. Taking T1-1 SAS as example, the feasibility and applicability of the proposed method is verified.