A hybrid optimization method for reactive power and voltage control considering power loss minimization

This paper proposes a hybrid optimization method to optimally control the voltage and reactive power with minimum power loss in transmission grid. This approach is used for the Danish automatic voltage control (AVC) system which is typically a non-linear non-convex problem mixed with both continuous and discrete control variables. Firstly, a deterministic method is adopted to search out the local optimum assuming all control variables are continuous. Then, initiating from the result of the first step, a heuristic method is used to discretize the control variables searching for the optimum in the global range. This approach is tested on the detailed model of the western Danish power system in DIgSILENT Powerfactory, where massive discrete components i.e. tap-able transformers and switchable shunts are employed by AVC for loss minimizations.