CALGARY, Alberta - TransAlta Corp. , Canada's biggest investor-owned power generator, said Monday it had closed the C$850 million ($545 million) sale of its Alberta transmission business, and will funnel the proceeds into its main electricity generation and marketing operations.

TransAlta, which announced the sale to a new consortium called AltaLink last July, said it would record a gain of C$100 million, or 59 Canadian cents a share.

The company has shed several non-generating operations in recent years to focus on its coal- and gas-fired power plants in Canada, the western United States and Mexico.

AltaLink comprises Canadian engineering and construction company SNC-Lavalin Group Inc., independent U.S. transmission firm Trans- Elect Inc., the powerful Ontario Teachers' Pension Plan Board and Australian investment bank Macquarie Group.

All are new entrants into the western Canadian province's recently deregulated electricity sector.

The sale of the unit, which includes 11,600 km (7,200 miles) of high-voltage lines, 260 substations and 250 workers, had required regulatory approval.

Shares in TransAlta were unchanged at $22.22 in Toronto Monday.