Most of Canada’s provinces and territories are part of interconnected electricity grids that cross international, provincial and territorial borders. Canada has three power grids: the Western grid, the Eastern grid, and the Quebec grid, which includes Atlantic Canada. The border between the Eastern and Western grids is the Alberta-Saskatchewan border. Canadian grids are also tied into the US.grids (the Western Interconnection, the Eastern Interconnection and the Texas Interconnection). For example, the electricity grid in Alberta and British Columbia is part of the Western Interconnection in the United States.
There is a predominantly north-south pattern to Canada’s transmission high voltage lines. This has emerged over time as utilities develop generation sites in northern areas of the country to produce and transmit electricity to urban markets in the south. Hydro-Québec’s system, for example, extends more than 1,100 kilometres from Churchill Falls in Labrador to Montreal, and from James Bay to southern load centres, which include U.S. markets. In Manitoba, a large 500 kilovolt DC system brings hydropower from the Nelson River to customers in the Winnipeg area. In Ontario and British Columbia, major 500 kilovolt systems bring electric power from northern generating sites to markets in the south.
any voltages are used by the various systems. These include 500, 450, 300 and 250 kV DC; and 765, 735, 500, 345, 230, 138, 115, 72, 46, 34.5, 24.5, 24, 13.8, 13.2, 12, 9, 7.2, 6.9, 4.8, 4.16 and 2.4 kV AC.
The total installed circuit length of transmission lines (50 kV and above) in Canada in 2009 is 190,019km.
The Canadian distribution system
In Canada, distribution companies may be owned by governments or by private investors. Depending on the province or territory, distribution services may be delivered by vertically integrated utilities, which are responsible for generation, transmission and distribution services, or by different electric distribution companies.
In Ontario, for example, the distribution of electricity is carried out by over 90 publicly and privately owned local electricity distribution companies (LDCs or distributors). Each company is responsible for maintaining their community’s network of distribution wires, and is the primary electricity billing agent in their franchise area. The size of their customer base and geographic area varies significantly. The largest distributor is Hydro One, which serves about one-quarter of Ontario’s 4.4 million distribution customers.