Currently, the proliferation of the renewable energy resources(RES), especially solar photovoltaic (PV), causes over-voltage and line over-loading in distribution network. This paper proposed two-level volt/var control(VVC) according to multiple timescale. In the hourly timescale, the on-load tap changer(OLTC) and capacitor banks (CBs) that have slow response speed operates to control the bus voltage. According to inverter’s volt/var curve in IEEE 1547 standard, the PV inverters are obliged to compensate reactive power based on the bus voltage. Therefore, in the 15-min timescale, PV inverters compensate reactive power which follows volt/var curve. This paper proposed new volt/var curve as the form of multi-sectional volt/var curve(MSVVC) to reduce total energy loss and obtain capacitor banks (CB) margin. To refect intermittency and uncertainty of the RES generation, the stochastic modeling is utilized. Then, the nonlinear optimization solver is used to find optimal parameter in MSVVC, and is verified on the IEEE 33-bus system and compared with conventional volt/var curve cases. |