Variable bandwidth computation for tap changer control in distribution grids

The growing share of distributed generation and electric vehicles has led to an increased deployment of on-load tap changers for voltage regulation in distribution grids. This trend entails changing requirements for tap changer control. This paper briefly discusses some recent developments in this field, while we focus on the variable bandwidth concept and its computational methods. Three different computation techniques are introduced. By means of a set of simplified equations, in-depth insight into the variable bandwidth concept is gained. For simple grid configurations this concept is suitable for bandwidth determination. For more complex networks we introduce a more accurate method using power system simulations. However, for realistic grids we propose an equally accurate, yet computational more efficient approach based on optimization.