Maschinenfabrik Reinhausen (MR) has built and delivered three giant de-energized tap-changers for the Canadian transformer manufacturer PTI Transformers.

These large tap-changers measuring ten feet (three meters) in length and 3.2 feet (one meter) in diameter had to maintain test voltage of 1,000 kV and switch 112 kV in a single step, the manufacturer said in the statement.

The tap-changers were delivered to PTI Transformers which had been contracted by a Canadian energy provider to manufacture a replacement transformer for a unit at a hydroelectric power plant that had reached the end of its service life.

The new transformer had to be able to switch between one transmission line at 250 kV and another at 143 kV in a single step, which required six high-voltage winding strands for every phase. For PTI Transformers, this meant housing 18 windings and three of the massive tap changers within the transformer.

Source: MR