Distribution transformer based smart grids with rooftop solar : a case study for Sri Lanka

Abstract

Trends on utilizing distributed renewable resources around the world have significantly increased the number of grid connected solar photovoltaic systems in low voltage networks. In Sri Lanka, low voltage systems are now available with the cumulative addition of the installed rooftop solar capacities is exceeding fifty percent of the rated capacity of the connected transformer. Thus, it is of vital importance to understand the technical impacts of solar photovoltaic additions in large scales on the operating performance of the networks and how to mitigate those issues. In this study, a futuristic solution is proposed with the formation of smart grid type operation, to effectively utilize the daytime solar photovoltaic generation in low voltage systems within the distribution transformer service area. Distribution transformer based smart grid, which operates with controlling mechanisms, loads, rooftop solar and battery storage systems is proposed for an urban low voltage distribution network in Sri Lanka which have more than forty percent of solar penetration level based on transformer capacity. The detailed network was modeled in MATLAB/SIMULINK simulation platform in order to develop different operating scenarios. The base model was validated with the field data available with transformer meter.