Frequency Stability in Renewable-Rich Power Systems with High Solar Ramps

The rapid integration of renewable energy sources into power systems is outpacing the implementation of solutions to address the stability challenges they pose. This study focuses on the impact of rapid ramp-down incidences of solar power plants on the stability of isolated power systems with high non-conventional renewable energy penetration and minimal support from thermal plants. Key issues include the intermittency of renewables, reduction of system inertia, and unpredicted ramp events. By using a simulated scenario based on the IEEE 14 bus system, comprising hydro and solar generation plants, this research identifies the maximum ramp-down rate and duration that the system can withstand without compromising stability. Hydro power plants, with their flexible and quick response capabilities, are critical for frequency control and system stabilization. Solar power plants, representing the most widely used non-conventional renewable source, add variability to the system. The simulation involves adjusting the irradiation levels of a 280MW solar power plant to model various ramp-down scenarios, using PSCAD software to observe system frequency behavior. The study tests multiple ramp rates and durations to determine the threshold at which the system frequency drops to 49.5Hz, the minimum acceptable frequency for a 50Hz system. The findings provide valuable insights into the ramp rate tolerance of renewable-rich isolated power systems, offering guidance for enhancing system stability amidst increasing renewable energy penetration. This research underscores the importance of strategic planning and implementation of responsive control mechanisms to ensure the reliable operation of future power systems.