McNeill HVDC Back-to-back station, HVDC back-to-back station in Cypress County, Canada

McNeill HVDC Back-to-back station is a power conversion facility in Cypress County that links the electrical grids of Alberta and Saskatchewan. It converts alternating current to direct current, allowing electricity to flow between two provincial networks that operate independently.

McNeill went into service in 1989, built by GEC-Alstom to link the Alberta and Saskatchewan grids, and was the first HVDC installation to dispense with the DC smoothing reactor. It was also the first HVDC station to use three-phase, four-winding converter transformers, with a 25 kV tertiary winding feeding the harmonic filters. In January 2012 Alstom won a contract to replace the analogue control system with a digital one.

The station's name comes from the McNeill area of Cypress County, and its converters tie Alberta's 138 kV grid to Saskatchewan's 230 kV grid. Because the two provincial systems are not synchronised, power crosses the border only through this direct-current link, which was built by GEC-Alstom.

The station is located in a remote rural area and is not open to public visits as it is a sensitive energy infrastructure site. Visitors can observe the facility from a distance and should maintain respectful boundaries from all equipment.

The station operates with one of the lowest Effective Short Circuit Ratios ever recorded for a line-commutated HVDC converter, functioning below 1.0 on the Saskatchewan side. This technical characteristic allows it to work in an extreme operating condition that would not be possible for other similar systems.