Receding Horizon Control of Wind Power to Provide Frequency Regulation

Abstract

With the increased penetration of wind generation in power systems, there is a rising interest in the provision of frequency regulation by wind turbines in order to relieve the burden on remaining conventional generation units. As a first step, the possible contribution of wind power to frequency regulation by optimally anticipating load imbalances in the power system is investigated. This ability is studied by implementing a receding horizon control which takes future load and wind variations into account. In this way, the available energy reserves of the wind turbine over a certain time horizon are optimally exploited to damp frequency oscillations while keeping the energy losses within defined limits. Results indicate that the receding horizon controller will mainly damp overfrequencies as its upward regulation capability is restricted to the available kinetic energy in the turbines. Moreover, it is shown that load forecast errors only slightly influence the results as the controller iteratively determines the optimal trajectory. Even if no load forecast is available, the proposed controller is still capable of damping frequency variations resulting from the simulated load profile by 25%, while keeping the energy yield above 97% compared to optimal power point tracking.