ReMIROR: Reference Modulation for Improved Response of Microgrid Resources

Washington State University, Pullman WA

Investigators

Abstract

One of the U.S. grand energy challenges is to enable integration of at least 80% renewable energy resources in the power grid at a competitive cost by 2050. While it is technically feasible to run the U.S. economy on renewable technologies available today, what is missing is a flexible power system that can accommodate the unique characteristics of renewable resources, such as their susceptibility to overcurrents and overvoltages due to power electronic interfaces. This project will address this challenge and accelerate the adoption of renewables by enabling them to deliver the required system performance via fast and accurate controls. The significance of this work is to eliminate the need for over-design by reducing transients and subsequently increasing asset utilization. Moreover, this work positively impacts industry because by reducing sensitivity to the individual design of controllers, controllers from different vendors can be employed. It should also contribute to enabling higher rates of integration of renewables, and is expected to have positive societal and environmental impact. The developed controllers can be adapted for different power system configurations, ranging from small isolated systems such as more-electric aircraft, naval ships, utility microgrids, and military camps, to DC-segmented systems. The educational goal of this project is to build human capacity for implementation/operation of the smart electricity grid through (i) workshops for underrepresented minority groups in high schools, (ii) curriculum enhancement through introducing innovative components in undergraduate and graduate courses, and (iii) developing new undergraduate and graduate courses. This goal addresses national concerns for producing skilled STEM professionals. The project team will develop schemes to autonomously improve set-point tracking capability of resources in a time-varying, limited-reserve system under various operating conditions. A prominent example of such systems is a microgrid. Microgrids have emerged as an enabling concept for the emerging smart power system. As dynamical systems, it is imperative for microgrids to have fast and accurate controllers. The performance of a controller deteriorates when the operating point of the host system varies significantly from that assumed in the original design. Redesigning controllers requires computational resources and a complete and up-to-date model of the system, neither of which are necessarily readily available in a microgrid. Moreover, the operator usually does not have access to the internal parameters of the controller. This project aims to augment the controllers that are already implemented with a strategy that monitors the response and modulates the reference set-point to attain the desired response. Specifically, this project will (i) build the mathematical foundation and stability studies based on discrete-event systems theory, (ii) design algorithms for generalized operation, e.g., under system imbalance and noisy measurements, and for providing advanced functions, e.g., rejection of disturbances due to faults and topological changes, and (iii) perform real-time simulation and experimental validation. The salient features of the proposed strategy will be (i) robustness to changes in the system, (ii) not requiring knowledge of the system model, and (iii) scalability and reliance only on local signals. This project will be transformative because it has the potential to accommodate different control designs from implemented by various vendors.