Control of PV systems for distribution network voltage regulation with communication delays

Abstract

Various approaches including the real power control through photovoltaic (PV) inverters have been proposed to address voltage issues due to high penetration of PV generators (PVs). However, most of the existing methods did not include communication delays in the control loop. Communication delays, short or long, are inevitable in the PV voltage regulation loop and can not only deteriorate the system performance with undesired voltage quality but also cause system instability. In this paper, a novel approach is presented to convert the overvoltage control problem via PV inverters for multiple PVs into a problem of single-input–single-output (SISO) systems. The method can handle multiple PVs and different communication delays. The impact of communication delays is then systematically analyzed and the maximum tolerable delay is rigorously obtained. Different from linear matrix inequality (LMI) techniques that have been extensively studied in handling systems with communication delays, the proposed method gives the necessary and sufficient condition for obtaining a controller and the design procedure is explicitly and constructively given in the paper. The effectiveness of the proposed method is verified by simulation studies on a distribution feeder and the widely-used 33-bus distribution test system.