Cooperative control of interfaced inverter with PV system and existing voltage control devices considering forecasted error in distribution system

In recent years, distributed generation (DG) and renewable energy source (RES) are attracting special attention to distribution systems. RES such as photovoltaic (PV) system are used as a source of green energy. However, the large amount of distributed generation causes voltage deviation beyond a statutory range in distribution systems. This paper proposes a methodology for voltage control by using inverters interfaced with DG and tap changing transformers. The proposed method which uses a one-day schedule of voltage references for the control devices are determined by an optimization technique based on forecast values of load demand and PV power generation. However, if the forecast value includes a forecast error, there is possibility that voltage control performance is affected. To solve this problem, this paper introduces the re-planning of control reference schedule in order to reduce the forecast error.