Inverter-based var control in low voltage distribution systems with rooftop solar PV

Drop in prices of PV panels and increased awareness of environmental concerns is resulting in high number of rooftop solar PV installations. Rapid irradiance changes on partly cloudy days causes severe fluctuations in PV power output resulting in rapid fluctuations in voltage, which makes large-scale integration of rooftop solar PV into the grid a major challenge. This paper presents an inverter-based var control strategy to damp fast fluctuations in voltages. Different reactive power control strategies for inverter-based PVs are studied and their effects are analyzed in a second by second time frame. The proposed strategies have been tested on the modified IEEE 37 bus test system. Simulations demonstrate that the proposed strategies outperform the current standard (IEEE 1547) for voltage control.