Avoiding MV-network expansion by distributed voltage control

Thanks to the fast expansion of Dispersed Generation (DG), Germany´s rural electric distribution grids are undergoing a process of rapid transformation to multidirectional energy networks. Latest analysis shows that new Voltage Controlled Distribution Transformers (VCDT) using an integrated on-load tap changer can not only be used for highly efficient LV grids, but might possibly be applied area-wide to avoid rural MV network expansion. VCDT technology opens up the static connection of conventional local transformers between MV and LV grids. It allows for the use of the entire voltage bandwidth of EN 50160 in each voltage level in an efficient way. In this paper, the idea of using VCDT-technology for an area-wide dispersed voltage control is at first explained, then shown in its effects on rural MV grids and finally discussed in its advantages and disadvantages.