Electricity is generated anytime there is a relative motion between conductors (commonly called wire) and a magnet. An electric generator is therefore a machine designed with conductors and magnet, requiring an external prime mover to create the needed relative motion. A common prime mover is a turbine, which is normally coupled to the rotating part of the generator.
The electrical and mechanical plant in the powerhouse has undergone a regular maintenance program. In 1988, a study was initiated and completed, to determine the extent of the retrofit work required, and in 1989 the Akosombo Generation Station Retrofit Project (AGSRP) was started.
The other hydro-electric plant is at the Kpong Generating Station
Technical Details of the Akosombo Dam
Maximum height from bedrock - 114m (374.00ft)
Height at axis from bedrock - 111m (364.17ft)
Height above tail water level - 73.2m (240.15ft)
Length of main dam at crest - 660m (2165.33ft)
Length of saddle dam - 355m (1164.68ft)
Width of dam at bed of river - 366m (1200.77ft)
Volume of material in main dam - 7943520m 3 (26061100.42ft 3)
Area of Lake - 8502sq.km
Capacity of Lake - 148 x 10 12 litres
Shoreline - 7250km
Length of Lake - 400km
Height of saddle dam - 37m (121.39ft)
Max. operating level - 84.73m (278ft)
Min. operating level - 73.15m (240ft)
Maximum water level ever recorded - 84.59m (277.54ft) on
8th - 9th November, 2010
Minimum water level ever recorded - 71.62m (234.96ft) on
21st - 25th July, 2007
TECHNICAL DATA
Turbine
Unit output - 173.1MW (222000hp) (Retrofitted Units)
Head (Max) - 68.88m (226ft)
Synchronous speed - 115.4 Rev/Min
Type of Turbine - Francis, Vertical shaft
Manufacturer - VA Tech, Voest Alpine, Austria
Generator
Rating - 179.95MVA at 14.4KV, 09PFM
Manufacturer - General Electric , Canada
Exciter
Type: - Static (SILCO-5)
Manufacturer - General Electric , Canada
Unit Transformer
Type - Outdoor 3phase
Rating - 200MVA, 14.4/161KV
Cooling - OFAF
Manufacturer - General Electric , Canada
Governor
Type - Electronic/Hydraulic
Manufacturer - Voest Alpine, Austria
Penstock
Type - Steel, one per unit
Diameter - 7.2m (24ft)
Length - 112m (368.1ft) to 116m (380ft)