The introduction of vacuum technology marks the beginning of a new phase—with longer service life, reduced wear, and new possibilities.
As with the Type M, MR has ushered in a new era with vacuum switching technology with its Type VT.
One of the main issues with an oil-filled OLTC is the oil degradation caused by switching arcs. This is especially true for selector switches, as the insulating oils for the switching duty and the overall device insulation are not separated. It was therefore logical to begin leveraging the advantages of switching with vacuum interrupters in the selector switch design, particularly since electrical parameters such as load current and voltage insulation seemed more manageable. The result was MR’s Type VV, the first OLTC for power transformers in the lower and medium power ranges to utilize vacuum switching technology. It is thus the first of its kind.
