Hydro-Québec's electricity transmission system (also known as the Quebec interconnection) is an international electric power transmission system centred in Quebec, Canada. The system pioneered the use of very high voltage 735-kilovolt (kV) alternating current (AC) power lines that link the population centres of Montreal and Quebec City to distant hydroelectric power stations like the Daniel-Johnson Dam and the James Bay Project in northwestern Quebec and the Churchill Falls Generating Station in Labrador (which is not part of the Quebec interconnection).
The system contains more than of lines and 530 electrical substations. It is managed by Hydro-Québec TransÉnergie, a division of the crown corporation Hydro-Québec and is part of the Northeast Power Coordinating Council. It has 17 interconnectors with the systems in Ontario, Newfoundland and Labrador, New Brunswick, and the Northeastern United States, and features 6,025 megawatts (MW) of interconnector import capacity and 7,974 MW of interconnector export capacity.
Major expansion of the network began with the commissioning of the 735 kV AC power line in November 1965, as there was a need for electricity transmission over vast distances from the north to southern Quebec.
Much of Quebec's population is served by a few 735 kV power lines. This contributed to the severity of the power outage following the North American ice storm of 1998.
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History
The first hydroelectric stations in Quebec were built by private entrepreneurs in the late 19th century. In 1903 the first long-distance high-voltage transmission line in North America was built, a 50 kV line connecting a Shawinigan powerstation to Montréal, away. In the first half of the 20th century, the market was dominated by regional monopolies, whose service was publicly criticised. In response, in 1944 the provincial government created Hydro-Quebec from the expropriated Montreal Light, Heat & Power.
In 1963 Hydro-Québec purchased the shares of nearly all remaining privately owned electrical utilities then operating in Quebec and undertook construction of the Manicouagan-Outardes hydroelectric complex. To transmit the complex's annual production of about 30 billion kWh over a distance of nearly , Hydro-Québec had to innovate. Led by Jean-Jacques Archambault, it became the first utility in the world to transmit electricity at 735 kV, rather than 300–400 kV which was the world standard at that time. In 1962, Hydro-Québec proceeded with the construction of the first 735 kV power line in the world. The line, stretching from the Manic-Outardes dam to the Levis substation, was brought into service on 29 November 1965.
Over the next twenty years from 1965 to 1985, Quebec underwent a massive expansion of its 735 kV power grid and its hydroelectric generating capacity. Hydro-Québec Équipement, another division of Hydro-Québec, and Société d’énergie de la Baie James built these transmission lines, electrical substations, and generating stations. Constructing the transmission system for the La Grande Phase One, part of the James Bay Project, took 12,500 towers, 13 electrical substations, of ground wire, and of electrical conductor at a cost of C$3.1 billion alone. In less than four decades, Hydro-Québec's generating capacity went from 3,000 MW in 1963 to nearly 33,000 MW in 2002, with 25,000 MW of that power sent to population centres on 735 kV power lines.
Source of the electricity
Much of the electricity generated by Hydro-Québec Generation comes from hydroelectric dams located far from load centres such as Montreal. Of the 33,000 MW of electrical power generated, over 93% of that comes from hydroelectric dams and 85% of that generation capacity comes from three hydroelectric generation centers: James Bay, Manic-Outardes, and Newfoundland and Labrador Hydro's Churchill Falls.
James Bay
The James Bay Project encompasses the La Grande project, which is located on the La Grande River and on its tributaries, such as the Eastmain River, in northwestern Quebec. The La Grande project was built in two phases; the first phase lasted twelve years from 1973 to 1985 and the second phase lasted from 1985 to present time. In all, the nine hydroelectric dams there produce over 16,500 MW of electric power, with the Robert-Bourassa or La Grande-2 station generating over 5,600 MW alone. In total, the project cost over C$20 billion to construct.
Manic-Outardes power stations The Manic-Outardes river area in the Côte-Nord or North Shore region consists of several hydroelectric facilities located on three principal rivers, from west to east: Betsiamites River, Rivière aux Outardes, and the Manicouagan River. A single plant named Sainte-Marguerite-3 is located to the east on the Sainte-Marguerite River (Sept-Îles). The facilities located in the region were constructed over a period of five decades, from 1956 to 2005. The total generation capacity from these power stations is 10,500 MW. A 21-MW hydroelectric power station, the Lac-Robertson generating station on the Lower North Shore, is not connected to the main Quebec grid. Churchill Falls
Churchill Falls is a single underground generation station located on the Churchill River near the town of Churchill Falls and the Smallwood Reservoir in Newfoundland and Labrador. It was constructed over a period of five to six years from 1966 to 1971–72 by the Churchill Falls (Labrador) Corporation (CFLCo), though generators were installed after major construction was completed. The single generation facility cost C$946 million to construct and produced 5,225 MW of power initially after all eleven generating units were installed. A station upgrade in 1985 raised the generating capacity to over 5,400 MW. Hydro-Québec Generation owns a 34.2% interest in CFLCo, which is the same company that constructed the generating plant. However, Hydro-Québec has rights to most of the 5,400 MW of power the station produces under a power purchase agreement, expiring in 2025.
Electricity transmission system features The system contains more than of lines and 530 electrical substations. It is managed by Hydro-Québec TransÉnergie, a division of the crown corporation Hydro-Québec and is part of the Northeast Power Coordinating Council. It has 17 interconnectors with the systems in Ontario, New Brunswick, Newfoundland and Labrador, and the Northeastern United States and 6,025 MW of interconnector import capacity and 7,974 MW of interconnector export capacity. The system has transmission lines reaching to power generation facilities located more than away from population centres. For this reason, TransÉnergie uses a voltage of AC 735 kV to transmit and distribute electrical power produced from Hydro-Québec's dams, although 315 kV is used as well. The total value of TransÉnergie's entire electricity transmission system is C$15.9 billion. For these reasons, Hydro-Québec TransÉnergie is considered to be a world leader in power transmission.
AC 735 / 765 kV power lines
From 1965 onwards, the 735 kV power line became an integral part of Quebec's power transmission backbone. More than one-third of Hydro-Québec TransÉnergie's system consists of high voltage AC 735 / 765 kV power lines, totaling strung between 38 substations with equipment of that voltage. The first transmission system from 1965 is an IEEE Milestone.
The physical size of the Hydro-Québec's 735 kV transmission lines is unmatched in North America. Only two other utility companies in the same region, the New York Power Authority (NYPA) and American Electric Power (AEP) contain at least one 765 kV line in their power system. However, only AEP has a significant mileage of 765 kV power lines, with over of 765 kV line traversing its broad transmission system; this system contains the most mileage in the United States under one electrical company. NYPA has only of 765 kV line, all of it contained in a single direct interconnector with Hydro-Québec.
The 735 kV power line is said to lessen the environmental impact of power lines, as one single power line operating at this voltage carries the same amount of electric power as four 315 kV power lines, which would require a right-of-way wider than the width required for a single 735 kV line. Each 735 kV line is capable of transmitting 2,000 MW of electric power at a distance of over and the entire 735 kV grid can carry 25,000 MW of power. Power transmission losses over the 735 kV grid range from 4.5 to 8%, varying due to temperature and operating situations. The Ordre des ingénieurs du Québec named the 735 kV power line system as the technological innovation of the 20th century for Quebec.
In the wake of the 1998 ice storm the Levis De-Icer was installed and began testing in 2007 and 2008.
Routes
Hydro-Québec TransÉnergie's 735 kV system consists of a set of six lines running from James Bay to Montreal and a set of four lines from Churchill Falls and the Manic-Outardes power stations to Quebec City. The South Shore region of Montreal and the Saint Lawrence River between Montreal and Quebec City contain 735 kV power line loops or rings.Google Earth images.
James Bay The James Bay hydroelectric dam complex contains several relatively short 735 kV power lines that send electricity to three principal substations, ordered from west to east: Radisson, Chissibi, and Lemoyne. From these substations, six 735 kV power lines traverse the vast expanses of taiga and boreal forest in clear-cut stretches of land; this shows up clearly in aerial photos. The terrain that the power lines cross is for the most part not mountainous, but smooth and replete with lakes. Generally, four of the lines runs together in two pairs and the other two run solo, although the two single lines sometimes do run in a pair. Two intermediate 735 kV power lines, one in the north and one in the south, connect all six power lines along their path to southern Quebec.
As the lines continue south, they diverge into two sets of three 735 kV transmission lines. The eastern set heads to Quebec City, where it connects with power lines from Churchill Falls and the 735 kV power line loops in the Saint Lawrence River region. The western set heads to Montreal, where it too forms a ring of 735 kV power lines around the city, linking to other power loops in the region. This section of Hydro-Québec TransÉnergie's power grid contains of 735 kV AC and 450 kV DC power line.
Manic-Outardes power stations / Churchill Falls
Electrical power generated from the Churchill Falls power station is sent to Montreal and the population centres of the Northeastern United States, more than away. Starting from the generation station in Newfoundland and Labrador, the power lines span a distance of over the Churchill River gorge and run generally south-southwest for as three side-by-side power lines in a cleared right-of-way with a width of . As they head southwest through boreal forest, the lines generally traverse flat, smooth rolling hills.
After the lines cross the Quebec-Labrador border, also known as the Hydro-Québec point of delivery, the direction of the lines becomes due south, and they head to the Montagnais Substation, a substation accessible only by an airport adjacent to it. A lone 735 kV line stems off from the substation, heading to an open pit mine the northwest. The terrain crossed by the power lines becomes hilly and mountainous south of the border. The lines reach over in elevation before descending.Google Earth elevations. The three lines continue heading south until they reach a substation on the North Shore of the Gulf of Saint Lawrence. From there on, the three lines parallel the North Shore as the Gulf narrows to the southwest toward the Saint Lawrence River discharge mouth. The northernmost power line then diverges from the other two to connect with Manic-Outardes power stations located on and around the Rivière aux Outardes and the Manicouagan River.