Zone simulation technique for distribution system reliability evaluation

This paper aims at presenting a zone simulation technique for reliability evaluation of power distribution systems. Reliability evaluation is considered an essential issue in the design and the operation of the distribution systems since researches have shown the contribution of the distribution systems to overall customer unavailability is quite significant. In this work, a zone-network model is introduced based on feeder partition method. Propositions are given to determine the failure effect. Then the simulation procedure is presented via the zone-network model. To improve the solution efficiency, simplified simulation method is also proposed. A computational software was developed to calculate average values and probability distributions of the individual load-point-reliability indices and the system indices, which provides a fast approach to the reliability evaluation of complex distribution systems with sub-feeders considering various practices, such as alternative supply, unreliability of automatic isolation devices and switches failures.