Comparative study of voltage regulation in distribution grid based on power electronic devices connected on the LV side of the MV/LV transformer

This paper presents a theoretical analysis of voltage regulation methods based on power converters that inject power on the LV side of the MV/LV transformer. Different converter connections are explored, either series, parallel or mixed. Analysis have been conducted in order to check the efficiency of the different solutions and their limitations, considering the structure complexity and the installed power. Concerning the purely reactive compensation systems, the results show that the mixed compensation structure based on both series and parallel has the greatest impact on grid voltage regulation, but that a structure allowing to exchange both active and reactive power could be even more effective. A prototype has been developed to present a simple and efficient way to do this regulation.