Super-Dordi Hydropower Project

1.1 General Arrangement  
It is a Run-of-River type of project utilizing water of Dordi Khola and collection of Purmu at the Adit site. The discharge of Dordi Khola shall be diverted to the left side of the river towards gravel trap. Course material up to 20mm shall be settled in Gravel Trap.

There will be inlet portal towards underground desander for the settlement of fine sediment of size up to 0.15mm. The headrace tunnel of 4.8km follows to underground surgetank at the end of horizontal portion after Taje Village on the ridge before Lodo Khola.

There are two intermediate adit at Prumu Khola and Kyame Khola. Prumu Khola discharge will be collected in headrace tunnel from the same access tunnel near purmu khola.  After the surge tank, there will be underground inclined penstock shaft which directly delivers flow to surface power house having vertical axis Pelton turbines. The discharge will be release back to Dordi Khola near confluence with Lodo khola from tailrace canal.

There will be generators, control panels, power transformers, 132kV switchyard and single circuit transmission line to proposed Dordi Corridor Hub at Kirtipur which is further connected to Udipur 220/132kV substation for power evacuation to national grid.  The company has signed connection agreement for the evacuation of the power through Udipur substation after 2017.

1.2 Salient Features
The following is the brief salient feature of Super Dordi Hydropower Project-Kha.

SNParticularSalient Features
1Project Location
Location of Project SIteDordi Gau Palika, Lamjung District, Gandaki Province
Longitudes84° 31 00” E and 84° 34 15” E
Latitudes28°16’ 20” N and 28° 18’ 43” N
2Project Type
Type of SchemeRun of River (RoR)
Installed Capacity54.0 MW + 10% Continuous Overload (CoL) i.e 59.4 MW-
Total Continuous Capacity
Gross head637.55 m
Design Discharge9.9 m3/sec at Q 40%
Energy After outage + loss3 14.983 GWh
Catchment Area142.45 sq km
Average Percipitation2035 mm/year
100 years Design Flood (HW)300 m3/sec
100 years Design Flood (PH)362 m3/sec
Design Discharge9.30 m3/sec (Q 40%) (Dordi HW) and 0.60 m3/sec (Q 40%) (Purmu) and total is
9.90 m3/sec (Q 40%)
Diversion StructureBroad Crest Free flow gravity weir
Length of weir18.5 m
Weir crest elevationEL 1887.6 msl
Height of weir17.5m from Foundation with Grouting
Crest of SluiceEL 1884.00 msl
Size of Sluice gates (bxh)3.0 m× 3.0 mx 1 nos
Intake TypeSide Intakes
Size of opening3.0 m x 1.5 m – 3 nos
Crest elevation of IntakeEl 1885.50 msl
5Gravel Trap
TypeD-Shaped Inside Inlet Tunnel
Particle Size to be settled20mm
Length of Gravel Trap36 m length
Size (Width X Depth)4.0mx (2.3-4.0)m
Bed Slope1:20(Settling Part)
6.Connecting Tunnel
Tunnel Length257.67 m from Gravel Trap to Desander
TypeInverted “D” Shape, Low Pressure Full Flow
Size of Tunnel4.2m (width) x 3.5 m (H)
Nos. of bend3 nos.
7Desander Basin
TypeLength=90 m x 2 Nos = 180 m
Underground Dufour Double Chamber Continuous
Flushing Type
Particle Size to be settled0.15mm
Size of Desander2 Chamber each of 10.6m X 8.6m x 100m length
Bed Slope1:50
Flushing Channel Size1.2 x 0.5 to 2.5 m
8.a)Headrace Tunnel (HRT)
Tunnel Length after Desander5158.66 m
TypeInverted “D” Shape, Low Pressure Concrete and Shotcrete Lined
Size of Tunnel2.8m Finished Diameter
Average tunnel slope0.25
Nos. of bend7 no.
Rock Trap2.8mX2.8m; 25 m length
Nitches3mx3mx 10m in length each 250 m
8.b)Purmu Adit for Headrace Tunnel
TypeInverted “D” Type, Shotcrete lined
Size of Tunnel2.8 m X 2.8 m
Length294 m
8.c)Kyame Adit for Headrace Tunnel
TypeInverted “D” Type, Shotcrete lined
Size of Tunnel3.5 m X 3.5 m
Length94 m
8Surge Shaft
TypeCylindrical Restricted orifice
ConstructionConcrete Lined underground
Dia of Tank6.0m
Dia Of orifice2.0m
Total Height49.2m
Invert LevelEL 1859.75m
Top LevelEL 1908.92m
Static levelEL 1387.60m
Upper Surge LevelEL 1905.42m
Operating LevelEL 1875.75m
Down Surge LevelEL 1867.05m
9Penstock Shaft
TypeSteel Lined Drop and Horizontal Shaft
Length1048m (Including Branches 45m)
Pipe MaterialHigh Strength Steel IS 2062-B E450
Size of Pipe2.2m dia to 1.8m dia 10-42mm thick
Number of Bends in Shaft5 Including Y
Number of Anchor Blocks12 nos.
Type of AditsInverted “D” Type, Shotcrete lined
Size of Adits35 m X 3.5 m. 346 m
TypeUnderground Power House Cavern
PH dimension51.3 m (L) x 15 (B) ×29.5 m (H)
Height / Width of PH building30.0 m / 15.0 m
CL of RunnerEL 1250. 1 m
11Tail race Tunnel
TypeInverted “D” Shaped, Shotcrete lined Free Flow Tunnel
Size (wxh)3.0 m x 3 5 m
Length423 m (Tailrace Tunnel) including branches
Number of Units2
Type of Turbine4 Jet Pelton, Vertical Axis, 600 RPM
Shaft ArrangementVertical
Rated discharge for each turbine4.95+10% CoLm3/s
Rated Head625.8m
Rated Output for each unit28000 kW+ 10% COL
Rated Efficiency91.50%
Speed GovernorElectro-Hydraulic (Electronics)
No of units2
Generator Type3 ph AC Vertical Synchronous, 50Hz
ExcitationBrushless excitation
Rated Voltage11.0 kV
Power Factor0.85
Rated Efficiency98.00%
Rated Output31.765MVA + 10% CoL
Rated Frequency50 Hz
14Power Transformer
TypeStep up power transformer
Capacity25MVAx 3 Nos, Single Phase
No of Units4 Nos x 1 ph, 50 Hz (including I Spare)
Type of CoolingONAN(Oil Natural Air Natural)
Primary (LV Side)11 kV
Secondary (HV Side)132 kV
ConnectionDelta/Star /Y
Overload Capacity120% for 4 Hrs.
15Station Supply Transformer
TypeIndoor type
Capacity250 kV A each unit
Number of Unit2
Type of CoolingDry Type
Voltage Ratio11.0/0.4, 0.23 kV
Connection /Vector GroupDyn11
16Transmission Line
Transmission Length6 km
Transmission Voltage132 kV
Type of CircuitDouble Circuit Tower
Proposed Interconnection PointNEA Interconnection Substation, Kirtipur
Line ConductorBear
17Power and Energy
Installed Capacity54 MW (formerly 49.6 MW)
Deemed Energy (Contract Energy in PPA)314.983 GWh
Dry Season Energy53.03 GWh
Wet Season Energy261 95GWh

1.3 Project Execution Parties

1.4 Capacity Enhancement

1.4 Contract Energy Table