This paper describes a methodology for determination of optimum failure rate and repair time for each section of a radial distribution system. An objective function in terms of reliability indices and their target values is selected. These indices depend mainly on failure rate and repair time of a section present in a distribution network. A cost is associated with the modification of failure rate and repair time. Hence the objective function is optimized subject to failure rate and repair time of each section of the distribution network considering the total budget allocated to achieve the task. The problem has been solved using differential evolution and bare bones particle swarm optimization. The algorithm has been implemented on a sample radial distribution system.
List of symbolsSAIFI System average interruption frequency index SAIDI System average interruption duration index CAIDI Customer average interruption duration index AENS Average energy not supplied k k , r k Failure rate and average repair time of k th distributor segment respectively L i Average load connected at i th load point k sys,i System failure rate at i th load point U sys,i System annual outage duration at i th load point N i Number of customers at load point i J Objective function k i,min and r i,min Reachable minimum values of failure rate and repair time of i th distributor segment k i,max and r i,max Maximum allowable failure rate and repair time of i th distributor segment SAIFI t, SAIDI t , CAIDI t and AENS t Target values of the respective indices CBUDGET The total budget available for preventive maintenance and corrective repair a K, b K Cost coefficients X ij 0 j th parameter of X i vector X j,min and X j,max Lower and upper bounds on variable X j rand j Random digit in the range [0, 1] r Scale factor X base (k) Base vector V ðkÞ i Mutant vector t i (k) Trial vector Cr Cross over rate or cross over probability j rand Random integer between [1,D] X ðkÞ i