The objective of this research is to improve the damping of inter-area oscillations in power systems by integrating damping controllers in grid-connected doubly-fed induction-generator-based wind farms. The approach is to employ two rotor control loops that allow independent modulation of active and reactive powers while providing damping benefits.
Intellectual Merits: This project addresses the problem of stability enhancements in power systems, given the increasing presence of and unique challenges in wind farms. The focus lies in developing robust damping controllers through a novel concept of real/reactive power modulation in wind farms to help mitigate instability concerns in the overall interconnected power system. The project will also help convey the benign effects of stability enhancements if grid interconnected systems are equipped with such controllers.
Broader Impacts: The project will help reduce some of the barriers to grid integration of wind farms. If successful, the research will facilitate penetration of large scale wind power into the existing grid. Increased integration of wind resources will benefit society by reducing fossil fuel dependence on electricity generation and thus help build a sustainable energy infrastructure. The educational plan will integrate research results with graduate courses on renewable systems modeling /bulk power system dynamics and continue the recruitment of qualified female students for graduate research. This project will help resolve some of the skepticism surrounding the stability of grid interconnected power systems. Overall, the activities will help promote and develop wind resources in the midwest region and the nation at large.
In this project, we explored the role of wind energy systems’ converters in system stability. The major outcomes of the project in the aspect of intellectual merits are listed as follows. The modeling technique (for wind energy machines, converters and grids) developed in this project makes analytical investigation possible for system-level issues such as inter-area oscillations and subsynchronous resonances. A dynamic modeling problem of Type 3 wind generator interconnected with a series compensated system was initiated in this project. Key findings were made through this research to show the different dynamic mechanisms of torsional interactions and electrical resonances. The adoption of impedance-model based frequency domain modeling and analysis shed insights on electrical resonances that occur in wind energy grid integration systems. Our research papers have been popularly cited by the community. The broader impacts of the project are as follows. A real-time digital simulation based lab at USF was initiated through the effort of this project. As a major outcome, an hardware-in-the-loop testbed was built at USF Smart Grid Power Systems lab. This testbed attracts more students in power system and renewable energy integration. The research findings were integrated into teaching of "AC Machines and Drives" offered at USF. A monograph is also planned to disseminate the research results. Two Ph.D. students and one master student working on this project graduated during the project period. They received career training through this project.
