Distribution Transformer with Multi-Zone Voltage Regulation for Smart Grid System Application

The article presents four concepts of the multi-zone voltage regulation (MZVR) system. It is a combination of a distribution transformer with an on-load tap-changer, for step voltage regulation, and a power electronic converter, dimensioned for a fraction of MZVR power, realizing continuous voltage regulation, supplemented by a special switch, the so-called bypass. This allows voltage regulation at high resolution, wide range and with high dynamics and increased reliability. The work contains selected computer simulation results of the continuous regulation system, and considerations about extending the MZVR continuous voltage regulation range and its power level.