Distributed Automatic Generation Control Using Flatness-Based Approach for High Penetration of Wind Generation

To allow for high penetration of distributed generation and alternative energy units, it is critical to minimize the complexity of generator controls and the need for close coordination across regions. We propose that existing controls be replaced by a two-tier structure of local control operating within a global context of situational awareness. Flatness as an extension of controllability for nonlinear systems is a key to enable planning and optimization at various levels of the grid in this structure. In this study, flatness-based control for automatic generation control (AGC) of a multi-machine system with high penetration of wind energy is investigated. The local control tracks the reference phase which is obtained through economic dispatch at the global control level. As a result of applying the flatness-based method, the n machine system is decoupled into n linear controllable systems in canonical form. Therefore, the control strategy results in a distributed AGC formulation which is significantly easier to design and implement compared to conventional AGC. Practical constraints such as generator ramping rates can be considered in designing the local controllers. The proposed strategy demonstrates promising performance in mitigating frequency deviations and the overall structure could facilitate operation of other nontraditional generators.