Mitigating the Effect of Wind Ramp Events on Local Run-of-River Hydropower Plants Using Cooperative Control

Abstract

This paper focuses on the challenges of frequency response from run-of-river (ROR) plants and potential solutions, especially considering the effect of wind ramp events in a low inertia power system. Due to sudden increases in instantaneous wind power, the system frequency can increase, causing excessive reduction in the ROR system's power. Considering their small pondage, this can result in damage to the physical structure due to water level violations which are also penalized by stakeholders. To prevent excessive ROR power deviations, ROR governor wear and tear, and to prevent tie-line deviations, a centralized coordination scheme with a balancing layer of distributed control has been developed for coordinating the response from a cluster of ROR plants. Results indicate that the centralized scheme both, with and without the balancing distributed control layer can reduce frequency peaks. However, the inclusion of distributed cooperative controls leads to reduced governor actions from fast-acting plants while enhancing net response from the hydropower cluster, and faster damping of tie-line power oscillations.