Impact of Residential Load Models for Overvoltage Prevention Studies in PV-Rich LV Grids

Selection of load models used in the study of power systems impacts the analyses being performed. Voltage-rise given the increased deployment of photovoltaic (PV) distributed generation presents technical challenges in low voltage (LV) distribution networks. Appliance consumption is naturally affected by the local voltage, a behavior taken into account by ZIP load models. PV generation is also affected by the local voltage because the inverters will not inject power if the voltage is not within a predefined range. An evaluation framework in MATLAB/Simulink, performed in OPAL-RT, is proposed to study the month-long technical analysis of the impact of the choice of load model for overvoltage challenges of PV-rich LV networks. A common droop-based active power curtailment PV inverter controller is implemented to evaluate a month-long technical impact on a 12-house LV distribution network. Analyses include voltage profile, energy generation and consumption, transformer loading, and system losses. The overall impacts of load model in the LV distribution system are presented and it is shown that overvoltage challenges are to an extent naturally reduced given the behavior of load.