MV/LV Network Interaction and Losses Based on Open-Source Simulation Tools Under High Renewable Integration

The integration of renewable energy sources into current power systems addresses new challenges for operation, particularly in terms of voltage stability and energy losses for both transmission and distribution levels. This work presents a simulation-based analysis of state variations in a real electricity network, with the goal of quantifying system losses and evaluating the impact of renewables on grid performance at medium and low voltage levels. Based on the resolution of the classic power flow problem, the analysis uses open-source, Python-based computational tools—specifically, the PyPower library—to simulate network behavior under varying seasonal conditions. Simulations are conducted over multiple time intervals to reflect temporal fluctuations in electricity demand, utilizing standard load profiles. The resulting datasets provide key electrical indicators, enabling the identification of critical nodes and time periods that may present operational or stability risks. The study focuses on four main objectives: (i) analyzing voltage performance in the High Voltage (HV) grid to identify critical nodes; (ii) comparing system performances under constrained and unconstrained reactive power profiles; (iii) estimating power losses across different scenarios; and (iv) assessing the contribution of Medium Voltage-Low Voltage (MV-LV) networks to overall losses. The case study is based on an anonymized, real-world electricity grid located in Denmark, characterized by multiple voltage levels and a high penetration of renewables. The case study provides a representative system for assessing the complexities of modern grid operation under such remarkable renewable integration.