Multivariable Control Structure Design for Voltage Regulation in Active Distribution Networks

The distributed generation (DG) paradigm has driven the growth of small and medium-scale renewable generation systems located close to demand centers. As a consequence, traditional distribution networks are in a transition towards the so-called Active Distribution Networks (ADNs). However, the intermittent nature of renewable generation causes rapid voltage fluctuations that are difficult to manage and deteriorate power quality. In the literature, the tasks corresponding to the design of voltage control in ADNs are addressed in a heuristic and sequential manner. In this work, a systematic strategy is proposed for the analysis, design and implementation of controllers for voltage regulation in ADNs with DG, based on the Plant Wide Control (PWC) theory of the Process Systems Engineering (PSE) community. This strategy allows us to find control structures that optimize the hardware necessary for its implementation and have good dynamic performance. The general PWC design procedure is formulated as a mixed integer two-level nonlinear programming with cost functions that only depend on the steady state models of the network. To evaluate the proposed methodology, the IEEE 33 distribution network model is used, to which 6 DGs are incorporated. The application of the proposed methodology to identify and evaluate different control structures contributes to the generation of systematic tools to approach the ADN control design process in a comprehensive manner, based on quantitative information.