Enhanced Network Voltage Management Techniques Under the Proliferation of Rooftop Solar PV Installation in Low-Voltage Distribution Network

Abstract

The proliferation of rooftop solar PV distributed generator (PVDG) installation in a low-voltage distribution network (LVDN) imposes voltage fluctuation challenges that are a threat to distribution system operators. Reactive power control (RPC) methods are insufficient in isolation to combat the overvoltage fluctuations manifested in an LVDN with a significant number of grid-tied PVDG installations, whereas active power curtailment (APC) control can alleviate the voltage fluctuation in such situations and it is achieved at the cost of reduced active power injection. This paper explores how deficiencies in both RPC and APC as separate approaches can be mitigated by suitably combining RPC and APC algorithms. Strategies combining two RPCs and one RPC in conjunction with APC are proposed as two coordinating algorithms by means of an instantaneous measurement of node voltage and active power. These coordinating algorithms are embedded in all the rooftop PVDG grid-tied inverters (GTIs), where the GTI coordinates among them for voltage support without exceeding individual inverter volt-ampere rating. The result of the combined approach shows a significant improvement in managing and stabilizing the voltage and allows the penetration of PVDG to be increased from 35.65% to 66.7% of distribution transformer kilovolt-ampere rating.