Power quality of residential PV system under low solar irradiance and off-grid operation

Abstract

Recent advances in grid-tied photovoltaic inverters are allowing more flexibility including Volt/VAR control, variable power factor operation, and adjustable ride-through capability. Some new inverters can now operate in stand-alone mode in case of a power outage during the daylight hours. Inverters are also known to supply currents that are highly distorted when operating under low solar irradiance. This paper evaluates how such distortion varies with the power produced by a modern single-phase PV inverter through field measurements. Additionally, the quality of its supply voltage, when operating off-grid, is analyzed in terms of its harmonic content under different loading conditions.