Risk analysis of a system is important to guarantee the quality and safety operation of a system. To identify the risky or critical components and to prioritize the safety improvements, Importance Measures (IM) play vital role. Risk analysis of a system using cost based importance measures is essential for system cost-risk analysis to reduce the maintenance cost. This paper presents the cost-risk analysis of Substation Automation System (SAS) using existing Cost Importance Measure (CIM) and an advanced cost based importance measure i.e NCIM which is easier, computationally more accurate and produce necessary ranking. The non cost based importance measures criticality, Fussel-Vesely (FV) and cost based importance measures CIM and NCIM for redundant cascading architecture of SAS have been determined. The results of criticality, FV, CIM and NCIM measures have been compared and the cost based importance measures yield more useful information compared to non cost based importance measures. From the outcome of these measures the components ESW and EI are important in cost-risk point of view and DCP is most important in maintenance point of view.