This report presents a detailed evidenced-based analysis of a selected substation in Erode District, Tamil Nadu, and explores the technical and commercial impacts of different solar PV penetration levels on the distribution network. The main objective of this report is to assess the benefits and challenges of integrating high levels of distributed solar generation at the distribution network level. This report provides evidence which shows that achieving high solar penetration levels up to 70% and 100% is technically possible and financially attractive.  It is targeted at utility companies, grid operators, policy makers and regulators and aims to contribute towards an enabling policy and regulatory environment for distributed solar energy generation in Tamil Nadu.