Optimal voltage control strategies for day-ahead active distribution network operation

• A coordinated voltage control (CVC) framework for day-ahead operational planning of active distribution network is proposed.
• The contribution of reactive power of distributed generation units as integral part of CVC is exhibited.
• The positive role of dynamic thermal rating (DTR) in the utilization of reactive power resources for CVC is demonstrated.
• DTR with combined voltage penalty and loss minimization objectives give the optimum network operation settings.
• The practicality of day-ahead active distribution network operation planning for CVC is discussed.

The aim of this study is to develop a coordinated day-ahead voltage control strategy for an active distribution network. A framework comprising a synergy of real-time dynamic thermal rating (DTR) and coordinated voltage control (CVC) is proposed for solving the voltage quality and thermal limit problems associated with a high penetration level of distributed generation (DG) in an active distribution network. The CVC scheme involves solutions such as On-Load-Tap-Changers (OLTCs), active and reactive power control of DG units, and switchable shunt VAR compensation devices (SVCs). Loss minimization and voltage penalty objective functions in the CVC optimization problem are compared. A 147 bus test distribution network planned for an actual geographical location is used to evaluate the proposed DTR-based day-ahead CVC strategy. In this study, we have showed that the reactive power absorption/injection potential of DG units can play an important role in CVC. Moreover, the study demonstrates that real-time thermal rating boosts the utilization of reactive power resources in the distribution system. Finally, the study investigates the practicality of day-ahead active distribution network operation planning for CVC.