RELIABILITY-ANALYSIS OF ELECTRIC UTILITY SCADA SYSTEMS

Electric Utility SCADA systems must be highly reliable given the poten tial for the SCADA system to directly contribute to load curtailment. This paper presents an analysis of SCADA system reliability in terms o f its expected, aggregate contribution to load curtailment on the powe r system. Expressing this aggregate in system minutes and applying an appropriate damage cost function then provides an annual cost measure of SCADA system reliability worth. A composite generation and transmis sion system reliability evaluation technique is used to perform the nu merical analysis of the joint SCADA and Power system model. This perfo rms a Monte-Carlo simulation and includes an optimal power flow for en umerating grid load curtailment states and analysis of SCADA system co mponent connectivity to determine availability of SCADA control. The a pplication of this analysis is illustrated in a comparison of two alte rnative SCADA architectures. Trans Power has adopted a subtransmission SCADA architecture which utilises terminals operating off its nationa l SCADA system. These terminals have replaced separate systems located in each area, The objective of the evaluation being to quantify the i ncreased exposure to financial losses due to joint load curtailment.