Separating diverter switch and tap changer opens up new degrees of freedom—for higher power ratings, more tap positions, and expanding grids.
Type D also had a similarly long production run of over 40 years as the Type C. Originally developed as a small-series production, Type D has become a long-running production model with various upgrades, some led to new type designations like Type F and Type E. The impetus for ongoing development was provided by constantly changing market needs regarding greater safety of supply in the face of steadily increasing energy demand and advancing network expansion.
MR’s Type D was designed as a diverter switch/tap selector OLTC. Separating the diverter switch and tap selector allows higher switching capacities (diverter switch) and a wider range of possible tap positions using different tap selectors than with selector switches, however, resulting in bigger dimensions. The different diverter switches were designed as single-, double- or triple-resistor designs which allowed higher max. step voltages and/or max. load currents. However, the switching sequence became more complex and was a challenge for the mechanical design/structure.
