Mahaweli Complex

Victoria is a 210MW hydro power project. It is located on Mahaweli river/basin in Central, Sri Lanka. According to GlobalData, who tracks and profiles over 170,000 power plants worldwide, the project is currently active. It has been developed in a single phase. The project construction commenced in 1980 and subsequently entered into commercial operation in 1984.

The Victoria Dam is located across the Mahaweli ganga immediately upstream of the Victoria falls rapids at about 130 miles from the river mouth. The site is about 72 aerial miles east of Colombo. 4 miles from Teldeniya. There is a good road from Colombo to Teldeniya distance about 84 miles. The present access from Teldeniya to the site is along the jungle track 4 miles long. The nearest railway station is Kandy.

Main contractors for the Dam and Tunnel were the Joint British Venture, Balfour Beatty Nuttal and the Power Station was contracted to Costan International.

Victoria dam is the highest dam in Sri Lanka and has the largest Power Station in the country. It consists of a double curvature arch dam of maximum height 122m (400ft), a circular concrete-lined tunnel of 6 meters diameter (19.7ft) leading to 3 Francis turbines, each of 70 MW capacity and generating 780 GIGA Watt hours, housed in a reinforced concrete power station 52 m (170ft) long and 30m (98ft) wide. The dam which is located between the Hulu ganga confluence and the Mahaweli ganga rapids called “Victoria Falls” measures 507m (1663ft) along the crest. The catchment area at this dam site is 1869 sq km(730sq miles) and the gross capacity of the reservoir is 728 M cu.m.(500,800 acre feet) at a full supply level of 438 m(1437 ft). There is a 21 meter (69ft.)diameter concrete-lined chamber to protect the tunnel from surge, effects.

Eight radial gates 12.5 meters (41 ft)wide and 6.5meters (21 ft) high are provided for the dam so designed as to open automatically when pre-determined water levels are reached. The design of these radial gates which require power only for closing, won an award for innovation in Civil Engineering from the Institute of Civil engineering (UK) for the consultants who designed them. The effective width of the over spill is 100 meters (328ft) and allows a maximum discharge capacity of 8,200 cu.m.per second (289,542 cusecs) under a head of 11 meters (36 ft). Two low level sluices are provided in the dam for drawing down the reservoir at initial filling or any subsequent time and also to pass silt which may accumulate immediately above the dam.

• Installed capacity 70 MW X 3
• Expected annual average energy 716 GWh
• Commissioned in 1984
• Main contractors
  • Civil – Costain
  • Electromechanical – GEC Large Machines
  • Hydro mechanical – Boving
• Located 40 km south-east of Kandy
• Reservoir
  • Catchment area : 1891 km2
  • Usable water volume : 688 MCM
  • Maximum level : 438 m above MSL
  • Minimum level : 370 m above MSL
• Headrace
  • Circular concrete lined
  • 6.2 m diameter
  • 5800 m length
• Penstock
  • Steel circular, 3 m diameter, 178 m length, With surge tank
• Tailrace
  • Length : VVV m ; Maximum level : 240 m above MSL; Minimum level : 230 m above MSL
• Generator (ASEA)
  • Conventional vertical
  • 70125 kVA, 0.85 PF, 12.5 kV, 3810 A
  • 50 Hz, 18 poles, 333 ⅓ rev/min
  • Exciter : 220 V, 1130 A
• Turbine (BOVING)
  • Vertical Francis
  • Output : 72 MW @ 190 m effective head (Rated), 83 MW @ 208 m effective head (Maximum)
  • Rated discharge : 35 m3/sec
  • 333 ⅓ rev/min