Voltage and Power Optimization in a Distribution Network with High PV Penetration

Abstract

Utilization of solar energy in distribution networks is on the rise, especially in the form of rooftop photovoltaic (PV) panels. Using smart inverters, it is now possible to allow PVs to inject both active and reactive power into the grid. However, high penetration of PVs can introduce operational challenges as it may cause voltage rise beyond the permissible limits and may lead to additional stress on system components. Also, if uncoordinated, injecting reactive power locally could interfere with the utility's efforts in controlling node voltages. Hence, a proper coordination among various electrical devices in the distribution system is necessary in order to pave the way for maximizing PV penetration and to minimize, concurrently, the overall system losses. In this paper an evolutionary algorithm (EA) is used in order to find the optimal settings of the controllable components in a distribution system in a centralized fashion. The control variables considered are PV active and reactive powers, load curtailment through demand response, tap positions of the voltage regulators (VRs), and status of switching capacitors (SC). The main objective of the proposed approach is to minimize system losses, operational variations of VRs and SCs, as well as curtailment in the PV active power. Two aspects are in particular investigated in this paper: the impact of PV reactive power support on the grid, and the effect of high PV integration on switching devices (SCs and VRs). The proof-of-concept simulation is conducted over a one-day period in order to assess the proposed optimal scheduling.