Assessment of voltage unbalance due to single phase rooftop photovoltaic panels in residential low voltage distribution network: A study on a real LV network in Western Australia

Voltage and current unbalance are common power quality problems in power grids. The penetration of single phase inverter interface photovoltaic panels will impact the voltage profile and voltage unbalance index of Low and Medium voltage distribution network. Due to lack of sufficient monitoring point in the distribution network, an assessment method of evaluating the voltage unbalance index is of paramount importance. Due to stochastic nature of the location and rating of photovoltaic panels, a probabilistic method based on Monte Carlo simulation is proposed to assess the voltage unbalance factor. The simulation is run using MATLAB and PowerFactory, based on proposed data exchange between the two software packages. The effect of the timing mismatch between solar generation and load profile is also studied using a time sweep simulation. The result of simulation shows that there is a low probability that the penetration of photovoltaic panels render the voltage unbalance factor to exceed the limits. However, the variation of solar generation and loads during the day might be of concern, especially during low demands periods.