Following the successful completion of commissioning tests, GE Energy's new variable frequency transformer (VFT) technology has entered commercial service for TransEnergie, Hydro Québec's transmission division, at its Langlois substation in Québec, Canada.

The project marks the commercial debut of the VFT technology, which provides a controlled path between electrical grids, permitting power exchanges that were previously impossible because of technical constraints, such as asynchronous boundaries or congestion. Hydro-Québec expects that the VFT technology will enable the Langlois substation, located in St. Timothée, Quebec, to transfer an extra 100MW of power between grids.

The VFT system is based on a combination of hydro generator and transformer technologies. It consists of a rotary transformer that provides a continuously controllable phase shift for any angle, and a drive system and control that adjust the angle and speed of the rotary transformer to regulate power flow. The VFT’s 100MW channels can be combined for up to 400MW in a single installation.

The commissioning process at the Langlois Substation included drive and rotational tests, round-power grid configuration, response-to-power commands, a heat run, energised tests for an isolated hydro plant, an isolated hydro generation unit trip, and energisd tests for a grid connection. GE reports that the tests met all of the design specifications for the VFT system.