New generation voltage regulation distribution transformer with an on load tap changer for power quality improvement in the electrical distribution systems

Voltage regulation distribution transformer (VRDT) is a solution to maintain supply voltage to its nominal value in the electrical distribution systems. The design presented in this paper is the new generation of VRDT equipped with an on load tap changer (OLTC), which enables voltage adjustment under loaded condition without interruption. The OLTC employed is a combination of high speed resistor type technology with vacuum tubes. The system is entirely safe and has a wide range of switchable currents from 30 A to 100 A with no significant additional losses. This advanced VRDT is designed, manufactured, tested and running successfully in the distribution grids.