This study addresses the emergency and operational transient processes that arise when integrating large-scale solar power plants (SPPs) into electrical load nodes, particularly under conditions of limited power system capacity. With the increasing penetration of distributed generation in Ukraine's energy landscape, challenges related to electromagnetic compatibility and harmonic resonance are becoming more prominent. The research builds upon the foundational work of leading Ukrainian scientific schools and focuses on the specific resonance phenomena observed during the operation of solar inverters in medium-voltage networks, especially in regions with high industrial and mining Energy demand. A novel algorithm is proposed for determining the amplitude-frequency characteristic (AFC) of load nodes with inverter-based generation, taking into account a wide range of operating conditions and system limitations. Analytical dependencies are derived to identify critical resonance frequency zones where voltage quality deviations may compromise system stability and the reliability of power supply to coal mines. Special attention is given to the 35 kV voltage level, which is prevalent in the connection schemes of system-forming substations. The study includes practical monitoring data from Ukraine's largest solar facility, the Pokrovska SPP, which serves as a real-world testbed for validating the developed models. Experimental observations confirm the formation of resonance peaks and AFC extremums depending on variations in grid topology, short-circuit power, and inverter group configurations. The modeling results highlight the conditions under which resonances are most likely to occur and provide recommendations for optimizing the placement and parameters of filter-compensating devices. The findings contribute to improved methodologies for predicting and mitigating resonance phenomena in electric power systems and enhance the overall reliability of solar power integration in Ukraine’s energy infrastructure and supporting sustainable energy management in mining-related industries.
Papaika et al. (Thu,) studied this question.