A Robust Algorithm for Volt/Var Control

This paper proposes an algorithm for Volt/Var control, where the control variables are both discrete (tap position of on-load tap-changing, OLTC transformers, switched-on shunt capacitor banks), and continuous (reactive power of generators). The optimization criterion considered is minimization of the system real power losses, subject to nodal real and reactive power balances and nodal voltage constraints. The corresponding nonlinear optimization problem is solved iteratively on two levels the Volt sub-problem is mixed integer programming (MIP) based master problem and the Var sub-problem is the mixed integer linear programming (MILP) based problem. The MILP problem is solved by Benders decomposition (BD). The proposed optimization method is formulated for the case of the uncertain input network model parameters to assess robustness aspects. Tire effectiveness of the proposed robust model for Volt/Var control is verified on the test example of a reduced New England/New-York interconnection with 68 nodes/86 branches/23 OLTC transformers/16 generators/9 switchable capacitors.