A practical approach for reliability evaluation of distribution networks

The authors describe a computer-aided method for the quantitative reliability evaluation of radial medium voltage networks. Reliability analysis is developed as part of a distribution network information and design system. The outage rates, outage durations and costs of outages can be evaluated using the data included in the network database together with the reliability data for network components and the per unit values for the energy not supplied. Using the reliability calculation program together with the other design programs, optimal development plans for each network can be studied. In these studies both the technical restrictions and the total costs-including the costs of investments, losses and outages-must be included. Using the program, utilities have chosen the optimum types of network investments to improve the reliability of their medium voltage networks. Practical experiences of these calculations at one utility are presented.