Maximising wind generation through optimised operation of on-load tap changing transformers in active distribution networks

On-load tap changing transformers are the most common control device to regulate and maintain distribution network voltage within required limits. Voltage rise issues on the other hand have become a major factor limiting greater penetration of low carbon generators, particularly in weak distribution networks. Here, the voltage rise problem is addressed through the application of optimised set-point voltage technique that aims to improve network hosting capacity to accommodate high wind penetration. It assesses the effectiveness of the technique on a realistic 289-node UK generic 11 kV distribution network using time-series optimal power flow simulations. The results reveal that when the tap changer is operated at the optimised set-point voltage, it can lead to greater energy yields. It also shows a reduction in the number of tap changing operations when the transformer is operated within the optimised deadband allowing for an improved life-span and minimum maintenance cost