Mitigación del impacto de la generación distribuida sobre la estabilidad de operación en sistemas de distribución eléctrica

Abstract

The IEEE 123-bus feeder was implemented in the DIgSILENT PowerFactory, operating at a medium voltage level of 4.16 kV, using unbalanced three-phase load flow (ABC) to realistically represent the asymmetric nature of the loads and the system topology. A baseline scenario without Distributed Generation was established as an operational reference, and subsequently, scenarios with connected Distributed Generation were analyzed through gradual increases in Hosting Capacity. Photovoltaic penetration was defined as a percentage of the head transformer capacity, using a transformer capacity of 2.5 MVA, and varying the power injection in 5% increments, from 5% to 100%, which allowed for the identification of the point at which the system began to experience operational limitations due to voltage. The evaluation criteria focus on the voltage level and its deviation from the nominal voltage at representative feeder busbars, with particular attention to the extreme and critical nodes, where sensitivity to injection changes is greatest. Specifically, busbar 59 of the IEEE 123 feeder is analyzed because it presents the most demanding conditions (critical busbar). Voltage variations are observed there, expressed in per-unit (p.u.), kilovolts, and as a percentage deviation, allowing for the characterization of the feeder's behavior in response to increased photovoltaic penetration. For compliance verification, the Ecuadorian regulatory framework for product quality is adopted, considering the voltage level limits established by ARCONEL for medium-voltage networks. This provides a regulatory basis for determining the admissible range and defining the maximum penetration that can be integrated without exceeding the established limits. Based on these results, the concept of Hosting Capacity, the maximum permissible capacity, is discussed. This capacity is defined as the highest percentage of photovoltaic penetration that allows the voltage to be maintained within the acceptable range in all phases and at critical nodes. Finally, the work proposes and justifies mitigation strategies aimed at preserving the operational stability of the system with high penetration of Distributed Generation.