Neutral Search Technique for Short-Term Pump Schedule Optimization

Abstract

This paper deals with the computation of short-term (typically 1day) least-cost pump schedule for water distribution systems with on-off type pumps and well-defined operating points. The objective function is to minimize the overall energy charge for a prescribed water consumption while several constraints are considered, such as storage and source limitations, pump setting bounds, nodal mass balances, and the power demand charge. In this study a neutral search technique with genetic algorithms (GAs) is proposed to solve the least-cost pump schedule problem where neutrality is achieved through objective-fitness mapping instead of representational redundancy. We introduce a fitness assignment technique for groups of individuals where grouping is based on objective similarity. As a consequence two different individuals can be equally fit (belonging to the same group) which implies the neutrality. We compare the neutral search technique to two conventional GA approaches on a hypothetical water distribution system.