Electric utility SCADA systems must be highly reliable given the potential for the SCADA system to contribute directly to load curtailment. This article presents an analysis of SCADA system reliability in terms of its expected aggregate contribution to load curtailment on the power system. To express this aggregate in system minutes and applying an appropriate damage cost function then provides an annual cost measure of reliability SCADA system.
A transmission system and composite generation reliability evaluation technique is used to perform the numerical analysis of the joint Power system and SCADA model. This performs a Monte Carlo simulation and includes an optimal power flow for enumerating grid load curtailment states and analysis of system SCADA component connectivity to determine availability of SCADA control.
The application of this analysis is illustrated in a comparison of two architectures of alternative SCADA. Trans Power has adopted a sub-transmission architecture of SCADA which utilizes terminal operating off its national SCADA system. These terminals have replaced separate systems located in each area. The evaluation objective is being to quantify the increased exposure to financial losses due to joint load curtailment.
Analysis reliability of Power System provides a means of determining when power system failures or load curtailment’s occur. SCADA failures are assumed to occur independently of load curtailment’s and occur when a power system. Operator is unable to retrieve data from or issue controls to primary plant associated with one or more busses. In each case the controls or retrieved data is a necessary part of load restoration. Determining whether a bus is uncontrolled or controlled is done by analyzing the availability of control paths through the SCADA system. This system is a detailed model representing the master station, remote terminal unit, SCADA data communications network and the data wide area network (WAN). Interest in SCADA reliability arose out of Trans Power adoption of a new centralized sub-transmission architecture of SCADA.