A Hybrid Decoupled Method For Tertiary Voltage Control of Active Distribution Networks

A tertiary voltage control (TVC) algorithm based on reactive optimal power flow (ROPF) is proposed to obtain reference voltages for pilot points in distribution networks. The algorithm employs a non-linear interior point method and differential evolution to minimise the overall distribution network's system losses. TVC is modelled as a hybrid decoupled optimal power flow problem transformed into two partial duality sub-problems. The reactive power sub problem is modelled as a quadratic programming problem, and the active power sub problem is modelled as a linear programming problem. Numerical simulations are performed using the IEEE 123 node distribution feeder to demonstrate the algorithm's efficiency, and it is observed that the system losses are reduced by 29.4 per cent after optimisation. Finally, the method is compared further with other approaches to justify the superiority of the proposed hybrid method for distribution network's loss minimization.