Determination of Optimal Distributed Generation Penetration Level in Distribution Networks based on Normalized Impact Factor Score

The penetration level of renewable energy (RE) including distributed generation (DG) integrated in the distribution network has been increasing in many countries. This follows widespread encouragement to use renewable energy to minimize reliance on conventional power plants to achieve net zero emissions. Malaysian energy transition targets and carbon neutral goals set by the government, lower cost of ownership of solar PV systems, and more efficient government renewable energy initiatives including Net Energy Metering (NEM) 3.0, Green Investment Tax (GITA), Large Scale Solar (LSS), and most recently the Corporate Green Power Program (CGPP) have driven the rapid development of renewable energy in the country. However, the high penetration level of distributed generation including solar PV, mini- hydro, and bio-energy has introduced several technical impacts on the operation of the distribution network including increased fault levels, voltage limit violation, reverse power flow, distribution network losses, and transformer losses. This paper analyzes the technical impacts of the high penetration level of distributed generation in medium voltage (MV) substations of the distribution network using DigSILENT PowerFactory simulation software. From the results obtained through the simulation analysis, the impact factors of fault level, voltage limit violations, reverse power flow, distribution network losses, and transformer losses have been formulated. The optimal distributed generation penetration level in distribution networks is then determined based on the highest score value of the normalized impact factor from all penetration levels.