Risk assessment of the secondary system of Smart substation based on function decomposition

The safe and reliable operation of Smart substations based on IEC 61850 is faced with new challenges because of the free distribution of functions, it's critical to carry out risk assessment of secondary system of smart substation. Based on the concept of function decomposition, secondary system is considered as the assembly of a series of closely linked functions. Structure entropy weight method is used to define the weight of every function. Taking account that the reliability of elements varies with operation time, the temporal behaviors of all functions risk are obtained, providing theoretical guidance for smart substation management.