MIMO design of voltage controllers for Distributed Generators

A large penetration of Distributed Generation (DG) may severely impact on the voltage profiles along LV distribution feeders. The first, cheapest and simplest step that can be undertaken is to involve DG units in the voltage control of the LV distribution networks, adopting a fully-decentralized architecture and avoiding any additional communication infrastructure. The paper proposes a design methodology for voltage control of DG units: a local controller measures and regulates the voltage at the node to which each DG unit is connected by acting on the DG reactive power injections and without any need for data or measurement exchange with other controllers. The controller design is based on a structural MIMO model of the distribution system and ensures a satisfactorily regulation, while avoiding any operation conflict among DG units. Stability analysis is also presented. The results of numerical simulations in PSCAD/EMTDC environment are discussed to validate the proposed approach.