Time-interval based volt/VAr control in distribution systems

In this paper, a new strategy for volt/VAr control in distribution systems is described. The purpose is to find proper dispatch schedule for on-load tap changer (OLTC) at substation and all switched capacitors based on the next day's load forecast. To avoid frequent switching operation of OLTC, a time-interval based control strategy is adopted in which a daily load at the substation is divided into several sequential load levels. A genetic algorithm is used in both load level partition and dispatch schedule searching. The proposed strategy can easily satisfy the number limitation of maximum allowable daily switch operations while minimizing the power loss and improving voltage profile in a whole day for the whole system. Numerical results illustrate the feasibility and effectiveness of the proposed approach.