The Development of 735-kV Transmission and Standardization at Hydro-Québec

2003-10-14

Hydro-Québec was formed on April 14, 1944, marking the beginning of the interconnection of Québec's various power systems and a long process of technical standardization. In the 1960s and 1970s, Québec nationalized electricity and started massive projects to develop Québec's hydroelectric potential.

Bringing energy from the North Shore to Québec City and Montreal was a major challenge that triggered a wave of research into solutions for minimizing the energy loss that comes with transmission over long distances. In 1955, no country anywhere in the world carried electricity at voltages higher than 400 kV (400,000 volts). The engineer Jean-Jacques Archambault and a handful of colleagues such as Don McGillis and Gilles Baril, studied how to design and promote the use of 735-kV transmission.

The first 735-kV line ever built, about 450 km long, was commissioned in 1965 and linked the Manicouagan and Rivière aux Outardes power stations to the load centres of Québec. This technology revolutionized the industry and made it possible to exploit the hydroelectric resources of Québec's northwest and northeast.

From its founding in the late 1960s, the Institut de recherche d'Hydro-Québec (IREQ) has been an active participant in developing the new technology for electrical power systems that traverse large distances. IREQ also helped standardize Hydro-Québec's generating, transmission and distribution equipment, a process made necessary by the 735-kV technology.

IREQ played a key role in the expansion of a modern and efficient power system, and researchers found innovative solutions to the problems posed by operating a 735-kV system. Hydro-Québec can now carry electricity at 735 kV over distances of more than 1000 km on a top-notch system that is reliable, safe and provides operating flexibility.

The experience acquired throughout this process has been distilled into standardized technical specifications. In the late 1970s, Hydro-Québec implemented a technical standards program and established norms in cooperation with the suppliers of generating equipment components (such as transformers and circuit breakers).

Training tools were required to standardize our practices and methods in order to:

Ensure the reliability of equipment

    * Promote the interchangeability of equipment
    * Encourage the grouping of purchases and reduction of inventory
    * Increase savings in labour and equipment
    * Reduce delays

 The expertise and progress that developed along with 735 kV technology, the development of alternative solutions, and the standards established by Hydro-Québec have enabled Hydro-Québec TransÉnergie and its engineering and project partners to play a major role on the international scene. Wherever the construction of high-voltage power lines permits the transmission of electricty over long distances, Hydro-Québec TransÉnergie and its partners are there!

Efforts are currently underway at Hydro-Québec to harmonize its technical standards with national and international standards, while ensuring that the requirements for its operating system-related particularly to a northern climate, long transmission distances, overvoltages, and series and shunt compensation-are taken into account. Most of Hydro-Québec's technical standards are based on standards in use throughout the world and match the closest CEI standards.

Most of the energy generated by Hydro-Québec is carried on high-voltage lines. With 735-kV technology, the environmental impact has been reduced: a single 735-kV line on the Hydro-Québec TransÉnergie system replaces four single-circuit 315-kV lines.

Hydro-Québec was the first to develop the commercial 735-kV line, and the accessories that operate at that voltage. Today, Hydro-Québec is still pioneering in high-voltage transmission technology. Québec's innovations have set standards that can guide any country that must carry electricity over long distances. High-tension lines have become a key technology for major systems.

Hydro-Québec's vision of the future embraces its ongoing participation in organizations such as the IEC and maintaining its leadership role in the electricity transmission industry.

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