Volt/VAr control in distribution systems using a time-interval based approach

A strategy for volt/VAr control in distribution systems is described. The aim is to determine optimum dispatch schedules for on-load tap changer (OLTC) settings at substations and all shunt capacitor switching based on the day-ahead load forecast. To reduce switching operations for OLTC at substations, a time-interval based control strategy is adopted that decomposes a daily load forecast into several sequential load levels. A genetic algorithm based procedure is used to determine both the load level partitioning and the dispatch scheduling. The proposed strategy minimises the power loss and improves the voltage profile for a whole day across the whole system, whilst ensuring that the number of switching operations is less than the maximum daily allowance. A comparison of numerical studies and their associated results illustrates both the feasibility and the effectiveness of the proposed strategy.