
THL has envisaged to develop Lower Seti (Tanahu) Hydropower Project located about 18 km downstream of the tailrace of Tanahu Hydropower Project. The peaking type ROR project with an installed capacity of 126 MW will have an estimated annual energy generation of 520 GWh with utilization of the flows of Madi River in addition to the regulated discharge of Seti River from the tailrace of Tanahu Hydropower Project.
Under the Grant-0361-NEP, Project Preparation Facility for Energy of the ADB, THL signed a Contract Agreement with JV of WAPCOS Limited, India and Nippon Koei Co. Ltd, Japan on 12 April 2019 for the Detail Engineering Design and Preparation of Bidding Documents of the project. After completion of the field investigation works, the Consultant has submitted the draft design report and bidding documents during the first quarter of 2021. As per the agreed plan with the ADB, THL has appointed international Panel of Experts (POE) for the independent review of design documents submitted by the Consultant. The POE has commenced the services and has so far submitted the first draft design review report to the THL.
Salient Features of the Project
Project Particulars | Details |
Project Location | Province (Gandaki Province) |
District | Tanahu |
Name of River | Seti River |
Headwork Site | About 24 km south from Damauli |
Powerhouse Site | Ghaighat (about 17 km from Mugling Bazzar) |
General | Type of Scheme(PROR) |
Full Reservoir Level | El. 275.0 m |
Minimum Draw Down Level | El. 272.0 m |
Normal Tail Water Level | El. 200.0 m |
Minimum Tail Water Level | El. 198.0 m |
Max. Gross Head | 77.0 m |
Min. Gross Head | 72.0 m |
Gross Operating Head | 75.33 m |
Net Head | 67.05 m |
Installed Capacity | 126.0 MW |
Energy after Outage | Total Energy (520.78 GWh) |
Wet Energy | 360.98 GWh |
Dry Energy | 159.80 GWh |
(Peak = 122.04 GWh & Off Peak= 37.76 GWh | |
Hydrology | Catchment Area (2,859 sq. km at Intake) |
19,800 sq. km at Power House | |
Design Discharge | 206.9 m3/sec |
Riparian Release | 5.08 m3/sec |
Design Flood Discharge | 9071 m3/sec (1 in 500 yrs. return period, n-1 gates) |
Design Flood Discharge | 10,096 m3/sec (1 in 1000 yrs. return period, n gates) |
Diversion Structure (Barrage) | Total Width of Barrage(200m at top) |
Total width between abutments | 110.5 m |
Total Length of Barrage | 213 m |
Length of Cistern | 85 m |
Nos. of gates | 6 |
Width of a spillway bay | 11 m |
Nos. of piers | 5 |
Width of a pier | 6 m |
Width of fish pass | 5m |
Width of a fish pass wall | 1.75 m |
Average River Bed Elevation | El. 246.0 m |
Under sluice Sill Elevation | El. 248.0 m |
Undersluice Opening (W X H) | 11m x 14m |
Barrage Crest Elevation | El. 277.0 m |
Cistern Elevation | EL. 240.3 m |
Power Intake | Type of Intake (Side Intake) |
Nos of Opening | 3 |
Size of an Intake (W x H) | 20.85 m x 24.5m |
Intake Sill Elevation | EL.252.5 m |
Nos. of piers | 2 |
Width of a pier | 1.62m |
No. of Coarse Trash rack | 3 |
Size of the trash rack (W x H) | 5.2 m x 24.5m |
Headrace Tunnel | Tunnel Shape |
Diameter of tunnel | 8.25 m (finished) |
Length | 6763 m |
No. of Adits along HRT | 3 |
Size of Adits (WxH) | 5.5 m x 7.5 m |
Rock Type estimation | Class 3 (20%), Class 4 (60%) & Class (5 &6) (20%) |
Surge Shaft | Type |
Effective Depth | 55 m |
Diameter (Or size) | 25 m |
Dia. Of Restricted Orifice | 3.5 m |
Invert of Surge Shaft | 231.37 masl |
Max. Up Surge Level | 293.5 masl |
Max. Down Surge Level | 249.5 masl |
Normal Operation Level | 275 masl |
Steel Penstock Pipe | Internal Diameter |
Length | 197 m |
Steel Thickness | 30 mm (varies) |
Powerhouse | Type |
Size (L x W) | 92.0 m x 32.0 m at erection bay |
Height | 47.0 m with steel roof |
Turbine Axis Level | 192.5 masl |
Tailrace | Type |
Tailrace Length | 82.0 m draft tube |
Tailrace Water Level (normal) | 200.00 masl |
Tailrace Water Level (min.) | 198.00 masl |
Turbine | Type |
Number | 3 |
Capacity per unit | 42 MW |
Net Head | 67.05 |
Turbine Axis Level | 192.5 masl |
Turbine Efficiency | 94.0% |
Generator Efficiency | 98.5% |
Governor | Type |
Adjustment for Speed Drop | Speed sensor |
Generator | Type |
Rated Output Capacity per Unit | 52 MVA |
Power Factor | 0.9 |
Generation Voltage | 11 kV+-5% |
Frequency | 50 Hz |
No of Units | 3 |
Transformer | |
Rated Capacity | 52 MVA, 11kV/220 kV |
No of Units | 3 |
Frequency | 50 Hz |
Transmission Line | Voltage Level |
Length | About 2 km |
Conductor Type | ACSR Bison |
From | LSHP Pothead Yard |
To | USHP-New Bharatpur Substation line in LILO scheme |
Project Cost Estimate | $ 180 Mil. (Base Cost) |
Construction Period | 5.5yrs |