Cost/benefit assessment of power system reliability
Value based planning in power systems is becoming increasingly important due to required system investment costs and the necessity to quantify and justify system reliability levels. Utilities faced with increasingly limited resources, strive to maintain high levels of reliability by adopting improved methodologies in planning, operation, construction, and maintenance. Many utilities now recognize that the total system cost used in the decision making process must include the value to the customers in the form of power interruption costs, in addition to investment and maintenance costs. Performing a reliability cost/benefit analysis requires an assessment of the costs of providing reliable service and quantification of the worth of having it. The annual expected values of the customer cost of interruption and curtailments can be added to the predicted annual investment and maintenance costs to form a total cost index for the specified project. Comparisons of various alternatives can then be made on the basisof the total cost. The main objective of this research was to develop a range of techniques to perform power system reliability cost/benefit assessment. An important aspect of the work was the development of techniques to conduct reliability evaluation for an overall power system. This required the utilization of a practical system configuration which includes generation, transmission, switching station and distribution facilities. This research extends an existing test system by developing the necessary distribution and subtransmission networks. The extended test system has all the main facilities that are found in a practical system. This thesis extends the available techniques and illustrates procedures for performing overall power system reliability evaluation. This thesis illustrates how system planners and operators can incorporate reliability cost/benefit assessment in a range of power system applications. A new approach to determine the optimum reserve in generation planning is presented. A new formulation for selecting the optimum number, locations and timing of line reinforcements in transmission planning is proposed taking into consideration investment, maintenance, resistive loss and unreliability costs. Station configuration design in a power system involves both reliability and economic considerations. This thesis presents a technique for optimum station configuration design selection utilizing reliability cost/benefit assessment. This thesis also illustrates the application of reliability cost/benefit assessment to determine the optimal routes and to obtain optimum switching device placement in distribution planning. The basic concepts associated with reliability cost/benefit assessment for an overall power system are illustrated by quantitative application to practical power system configurations.