The Influence of Service Availability on the Configuration of Underground Three-Phase Primary Systems

The configuration of the underground primary system has a direct bearing on service availability. For this reason, service availability should be a dominant criterion in determining the optimum configuration for underground three-phase primary systems. This paper examines the influence of primary circuit configuration on the frequency and duration of service interruptions and on the service restoration procedure. Various arrangements of radial, open loop, and dual feed system elements are considered, with both manual and automatic sectionalizing equipment. The availability performance of a variety of total system configurations is determined by combining these system elements.