CONTROL OF DISTRIBUTION NETWORK MODES WITH INTEGRATED SOLAR GENERATION: DEVELOPMENT OF A DIFFERENTIATED DISPATCHING METHOD USING THE UKRAINIAN POWER SYSTEM AS AN EXAMPLE

Abstract

This study addresses the critical challenges of integrating massive distributed energy resources (DER), specifically photovoltaic (PV) systems, into the low-voltage (0.4 kV) distribution networks of Ukraine amidst the war-driven shift towards energy decentralization. The rapid proliferation of household prosumers has significantly altered the operational dynamics of traditional weak rural grids. By analyzing real-world operational data from 23 prosumers in the Ivano-Frankivsk region during July 2024, the study identifies that high active resistance in 0.4 kV lines combined with significant active power injections leads to severe Voltage Rise (VR). Empirical results demonstrate that 66.7% of low-voltage prosumers experience VR exceeding 10%, threatening compliance with the EN 50160 power quality standard. Furthermore, a pronounced asymmetry was discovered: merely 21.7% of critical prosumers generate 105% of the aggregated peak power, causing the most severe grid disturbances. To mitigate these issues without excessive energy curtailment, an innovative adaptive Priority-Based Volt-Watt/BESS control algorithm is proposed. This approach categorizes prosumers into three groups (A, B, C) based on their Export Ratio. For high-risk prosumers (Category A), the algorithm prioritizes the dispatch of Battery Energy Storage Systems (BESS) to absorb excess generation. If BESS is unavailable, a strict Volt-Watt droop control is applied. For moderate-impact prosumers (Category B), a softer curtailment profile is utilized, while Category C remains under passive monitoring. This hierarchical control strategy ensures the maintenance of acceptable voltage levels across the network while minimizing forced active power curtailment. The proposed algorithm presents a scalable, cost-effective solution for Distribution System Operators to manage bidirectional power flows and enhance grid resilience.