Assessment of Transmission System Component Criticality in the De-Regulated Electricity Market

This paper describes a probabilistic approach for assessing the criticality of bulk transmission system components in the de-regulated electricity market. The proposed method is based on the analysis performed by the Hydro One probabilistic composite system evaluation program and use of a simplified reliability model for the transmission system network. The method accounts for random failures of system generators and transmission system components, transmission system component ratings, system load profile and generator bids during a specific period of time. The assessment method uses a performance criterion based on the total system energy cost in ranking transmission components in terms of their importance to the over all system performance. Sensitivity analysis is performed to determine the impacts of changes in some system parameters on the ranking of transmission components. The proposed method will enable power system planners and operators to identify the most critical transmission system components with regard to system reliability or system operating cost or both. Having identified the most critical components of the system, the next step would be to develop action plans that address individual component reliability and capability. Discussion on the individual component action plans is beyond the scope of this paper. The proposed assessment method is illustrated using the IEEE Reliability Test System.