Shading Analysis & Improvement for Distributed Residential Grid- Connected Photovoltaics Systems

Despite incentive reductions, distributed residential PV Systems continue to be installed throughout Australia in large numbers. Currently there are more than one million residential Photovoltaic (PV) systems installed across Australia (Australian Clean Energy Council, 2013). One of the significant challenges for residential roof top systems is the shading effects caused by various obstructions including trees, roof top structures and neighbouring buildings. Different levels of shading will lead to extraordinary performance variations in both individual solar modules and the entire PV array. This is primarily due to the operation of module bypass diodes contained inside the junction box. This paper will explain various shading scenarios and describe shading categories and classifications. Following the comprehensive research and analysis of module bypass diodes functionality and their pros and cons, a series of proposed installation solutions will be recommended to reduce shading losses.