Featured Projects
Bakun-Sabah AC Interconnection
Egypt-Jordan Interconnection
Emerald Switching Station
Isle of Lewis Wind Farm
Wuskwatim Generating Station


Great Falls Generating Station


Manitoba Hydro


Manitoba
     
 
 
The Great Falls Generating Station, built on the Winnipeg River, has the distinction of being one of the oldest hydroelectric generating stations owned by Manitoba Hydro. The first 21 MW unit went into service in 1922, and was followed by 5 additional units over the next 6 years. Major rehabilitation was completed in 1981, which was intended to extend the life of the plant by 50 years. Although electrical equipment in the 110 kV switching gallery has been upgraded at various times, safety issues due to non-standard electrical clearances are a major concern.

The switching gallery consists of 12 bays of air-insulated 550 kV BIL switchgear in a single breaker double bus arrangement housed in a 25 by 380 foot room on the top floor of the generating station. The 1950's style air blast circuit breakers are mounted very low to the floor, and together with freestanding current transformers leave very little room for an access corridor. The two main buses crowded together with the bus disconnect switches make maintenance difficult and dangerous.

Teshmont has carried out studies to identify methods of improving the situation. Although an upgrade program has not been finalized, it will likely involve replacing the aging air blast circuit breakers with dead tank SF6 circuit breakers, which incorporate current transformers in the circuit breaker bushings. These circuit breakers can be mounted higher with a safe distance to the floor and will allow more room for the access corridor. The double bus arrangement will likely be replaced by a simpler single sectionalized bus arrangement. Outages will be kept to a minimum with one unit and one transmission line being out of service at a time.

Other options such as replacing the air insulated indoor switchgear with gas insulated switchgear or building a new outdoor switchyard were investigated but were not favored because of cost and environmental licensing concerns.
  
 
   

Teshmont has provided, and continues to provide, the following services:

  • Preparation of reports identifying safety issues in the Great Falls Switching Gallery, options to address the safety issues, and estimated costs of the above options.

  • Studies to upgrade Great Falls Switching Gallery with SF6 dead tank circuit breakers.

  • Studies to convert Great Falls Switching Gallery from a double bus to a single sectionalized bus arrangement.

    		•