Two-phase BESS optimization methodology to enhance the distribution network power quality and mitigate violations

This paper proposes a two-phase optimization methodology to optimally dispatch the active/reactive power of battery energy storage systems (BESS) installed on the medium voltage distribution network to manage the violations and enhance the power quality and security. The first phase is look-ahead scheduling that aims to flatten the grid power curve and optimize the network power factor over the scheduling horizon using forecasted demand and generation. The second phase is a real-time model predictive control (MPC) introduced to adjust the BESS real power setpoints against network violations due to high uncertainties associated with the renewable generation and low carbon technologies as well as other unexpected events. Simulations were carried out for an actual 11 kV, 53-node distribution network located in Northern Ireland for two case studies representing the winter and summer. The results demonstrate the effectiveness of the proposed methodology in enhancing the network operation through optimizing the power factor, reducing line losses, and mitigating stresses. Sudden over/under voltage events were solved through the real-time phase efficiently without affecting the power factor or the line losses in a fast manner with a computation time of 0.52 s/time-point which makes it suitable for real-time control implementation.