Fit for the Future with an RMV-II

It was no April Fool’s joke when the City of Pratt in Kansas, Missouri went off-line on April 1. In fact the Reinhausen crew replaced an old McGraw Edison 550 type on-load tap-changer with a vacuum type RMV-II. The old arcing-in-oil type required maintenance nearly every two years, so the City of Pratt chose the replacement solution.

During the time the transformer was off-line, power supply was secured with an old 14MW steam generator. The Reinhausen crew thus only had a short time frame of two weeks for replacement. Having tested the transformer first, they de-installed the old type. The McGraw 550 types, manufactured in Canonsburg, Pennsylvania until 1990, have two leads per phase and one common lead, so the crew went to work on the preventive autotransformer (PA). After mounting the RMV-II, the cross lead test showed that everything was set up correctly. Then the cabinet was wired before the crew did a final check on the RMV-II and activated the motor drive. All done the transformer was vacuum processed and tested by the Reinhausen crew. The tests included TTR (turns ratio test), winding resistance and excitation plus power factor (capacitance and dielectric dissipation factor). Then the power transformer was put on-line again – after less than 11 days only so even some days ahead of schedule. Final statement from the customer was “I think you and your team have done very well. This will be an excellent flagship project for Reinhausen”.

The RMV-II is of course equipped with our smart Messko accessories, the oil level gauge and the maintenance-free breather. This type is, compared with other types in the market, a breather in which a sensor activates the heating. The moisture that is then extracted within this heating process drops out at the bottom through a stainless steel filter. The special design prevents it from choking. On customer request, data loggers can be installed as an option to confirm the correct functioning of the breather.

The RMV-II is our workhorse model and is the top-selling reactive type on-load tap-changer worldwide. It is also the most reliable one, working steadily from the Equator in Ecuador to the Arctic region in northern Russia. Experienced in LTC design and production, Reinhausen is also active in retrofitting on-load tap-changers throughout the world. The City of Pratt retrofit is just one example of what we can do.

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