Impact Assessment of Electric Vehicle Charging Station Using Advanced Static Load Modeling

The rising number of electric vehicle (EV) charging stations has significantly increased electricity demand on power system networks, leading to several challenges such as increased power losses, voltage deviations, and potential overloads on components like cables and transformers. A comprehensive power system analysis, considering the impact of EV charging loads, is essential for ensuring secure and reliable grid operations. This study examines the impact of EV charging on the Kathmandu Valley power network, part of the Integrated Nepal Power System (INPS). Previously, the impact of EV charging was often examined using a constant load model that did not account for voltage dependency, potentially leading to unfavorable outcomes. This research incorporates voltage dependency to accurately calculate the EV charging load. A Monte Carlo simulation was used to generate the EV charging profile based on data from a globally renowned EV company. The ZIP model coefficients, representing constant impedance (Z), constant current (I), and constant power (P), were determined via simulated annealing. Our findings indicate that the ZIP model adapts better to voltage fluctuations, resulting in improved voltage profiles and reduced line loading compared to the constant power load model. This voltage-dependent model provides crucial insights for power system planning and operation in regions with growing EV usage.