Impacto da evolução do curto-circuito na estabilidade angular do gerador síncrono em sistemas com alta penetração de fontes renováveis

Abstract

Among the various contingencies that affect rotor angle stability in Electric Power Systems, fault evolution stands out due to its potential to compromise secure system operation, leading to generator loss of synchronism, cascading outages, and reduced power supply reliability. Despite its operational significance, this phenomenon remains scarcely addressed in the scientific literature. Furthermore, the increasing penetration of converter-based renewable energy sources has reduced system inertia, making the stability of conventional synchronous generators progressively more vulnerable to disturbances. In this context, investigating the impacts of fault evolution on rotor angle stability is essential to provide a more realistic assessment of power system security and to support the development of strategies that enhance the reliability of modern electric power systems. In this context, this master’s thesis presents studies on the impact of short circuit evolution on the rotor angle stability of a synchronous generator installed in the adapted IEEE 34 bus distribution system with the integration of wind turbines and photovoltaic plants. To this end, the ETAP® software — Electrical Transient Analyzer Program — was used to simulate the IEEE system under short-circuit conditions that evolve spatially. The case studies show that increasing the penetration of renewable power plants reduces the Critical Clearing Time (CCT) and, consequently, indicates, for the analyzed system, a maximum penetration level of 60% relative to the system’s synchronous generation capacity to maintain stability. Additionally, the results demonstrate that short-circuit evolution acts as a limiting factor for rotor angle stability, reducing, for the analyzed system, the allowable penetration level from 60% to 20% in order to preserve the synchronism of the synchronous generator under evolving fault conditions. The transient stability of the system under three-phase faults applied in the vicinity of the synchronous generator was also evaluated, using the CCT as the performance metric. The results demonstrated that increasing the penetration of inverter based renewable energy sources progressively reduces the angular stability margins, as evidenced by the decrease in the CCT values observed across the different scenarios analyzed