VALUE-BASED DISTRIBUTION-SYSTEM RELIABILITY PLANNING

Society is becoming increasingly dependent on a cost-effective reliabl e electric power supply, Unreliable electric power supplies can be ext remely costly to electric utilities and their customers, Predictive re liability assessment combines historical outage data and mathematical models to estimate the performance of specific network and system conf igurations [e.g., IEEE Std, 493-1990], This paper is concerned with th e value-based assessment of proposed modifications to an existing indu strial distribution system configuration to minimize the costs of inte rruptions to both the utility and its industrial customers, This paper will present a series of case studies of an actual industrial load ar ea supplied by two feeder circuits originating from two alternate subs tations, Each case study will reveal the impact on the cost of industr ial load point interruptions and the frequency and duration of industr ial load point interruptions when various system constraints (e.g., id eal and nonideal protection coordination schemes, substation capacity restrictions, etc.) are imposed on the distribution system, The paper discusses in some detail the variance in reliability performance index es and their impact on the cost of load point interruptions, A basic c onclusion of this paper is that expansion plans of an industrial distr ibution system can be optimized in terms of reliability by using an ec onomic criterion in which the sum of both the industrial facility inte rruptions and the utility system costs are minimized.