Operational windows for decentralized control of renewable DG: Techno-economic trade-offs

The connection of renewable distributed generation (DG) is expected to increase significantly in the UK. A large volume will continue to connect to rural areas where voltage and thermal constraints are the main issues. It is in this context that Distribution Network Operators (DNOs) need to provide cost-effective connection arrangements, avoiding expensive reinforcements, and looking at innovative ways of actively managing the network. Herein, a decentralized, local control of (renewable) DG is proposed to manage voltage and thermal constraints by regulating the DG reactive power capacity and applying generation curtailment. Given that DG developers will require the highest possible returns of energy exports and DNOs might tolerate short-term, low-impact voltage and thermal breaches, the settings of the actual control mechanism (e.g., thresholds, target values and holding time) require special attention. This work focuses on the fine tuning of the control settings of the proposed scheme in order to assess the technical and economic trade-offs. A concept based on operational windows (related to time and severity) to capture the constrained situations is introduced. Results using a radial test feeder will be presented, highlighting the performance of different tuned settings.