ABSTRACT
The distribution system is a network that includes a number of segments for delivery of power supply at the load points. All the components of the electrical power system are exposed to various types of faults caused by lightning, open circuits, storm, component failure, tree falling on lines, equipment failure, short circuits, etc. Consequently, protective devices are integrated into the distribution system as a way to protect the power system and to minimize the economic impacts of power outages. The protective devices play a proactive role in the reliability of a power system by reducing the number, duration and frequency of power outages at the load points. Chapter 16 discusses the concepts of power system reliability and the quantification of the impacts of protective devices on the availability of power supply. The distribution network operators measure the reliability performance of their systems by using some reliability indices. However, utilization of the reliability indices is not sufficient to measure the cost and impacts of power outages on customers and utilities without considering the cost of the protective devices. The integration of protective devices into the distribution system can minimize the economic impacts of power outages, but this increases the investment costs of the protective devices. The formulation of the optimization problem discussed in the chapter is based on minimizing the reliability index (RI) and total cost (TC), which comprises the total outage cost, annualized maintenance cost and annualized capital cost. This objective is achieved by proposing an optimization technique for identification of the location and type of protective devices that can be used in the distribution power system to reduce the total cost of the power system. The validity of the concepts and techniques are demonstrated by analysing the results obtained from different case studies.
