Aerial view of headworks and dam site  area of Tanahu Hydropower project / latest progress on work/
Channel: Pusker
Date: 2022-12-31

Salient Features of the Project
Reservoir
Full Supply Level : 415 m
Minimum Operation Level: 378 m
Available Depth : 37 m
Sedimentation Level 320 m : 320 m
Gross Storage Capacity 295.1 × 106 m3 : 295.1 × 106 m3
Effective Storage Capacity: During first 10 years 192.8× 106 m3 After 11th year; 181.7 × 106 m3
Diversion Tunnel
Design Flood : 2,305 m3/s (20 years return period)
Numbers: 2
Type of Tunnel : Concrete lined pressure flow m
Length : Diversion Tunnel 1-606 m, Diversion Tunnel 2- 666 m
Inner Diameter : 10 m
Dam
Type : Concrete Gravity
Elevation of Dam Crest: 420.0 m
Height of Dam : 140 m
Length of Dam Crest : 215 m
Volume of Dam : 929 × 103 m3
Auxillary Dam
Type : Weir resting on bore piles wall
Length of Crest: 133 m
Height : 30.6 m
Volume : 121,980 m3
Sediment Flushing Facilities Inlet Sill Elevation : 320 m
Gradient of Conduit:1:15
Upstream Maintenance Gate Span x Height :Slide Type Steel Gate 5 m x 5m
Intermediate Main Gate Span x Height :High Pressure Slide Gate 5 m x 5 m
Downstream Auxiliary Gate Span x Height :High Pressure Slide Gate 5 m x 5.2 m
Spillway
Design Flood : (7,377 m3/s)
Type: Chute
Elevation of Overflow Crest : EL. 398.1 m
Width of Overflow Crest : 51.32 m
Energy Dissipater : Roller bucket
Type of Gate : Radial (4 Nos.)
Size of Gate (span x height) : 12.83 m x 18.1 m
Intake
Number : 1
Intake Type: Tower Type Intake
Gate Type : Vertical Lift Fixed Wheel Type Steel Gate
Size of Gate (span x height) : 6 m x 9 m
Headrace Tunnel
Number : 1
Inner Diameter: 7.4 m
Total Length : 1469.6 m
Surge Shaft
Type : Restricted Orifice
Shaft Height/Diameter: 28 m/ 61.5 m
Diameter/Height of Riser : 7.4 m/22.8 m
Diameter of Orifice : 5 m
Penstock
Type : Tunnel
Number: 1
Inner Diameter: 5.7 m to 4 m
Total Length : 160 m (including one (1) branch pipe length)
Draft Tunnel
Length : 99.4m
Type of Draft Gate: Vertical Lift Slide Type Steel Gate
Size of Draft Gate (span x height): 5 m x 3.1 m
Tailrace Tunnel
Diameter : 7.4m
Length: 213 m
Outlet Type: Outlet With Draft Pond
Type of Tailrace Gate : Vertical Lift Slide Type Steel Gate
Size of Tailrace Gate (span x height): 7.4 m x 7.4 m
Powerhouse
Type : Underground
Size: 22 m wide × 45 m high × 89 m long
Development Plan
Rated Intake Water level : 405.0 m
Tail Water Level: 289.2 m
Gross Rated Head: 115.8 m
Maximum/Rated Effective Head : 121.55 m/111.7 m
Maximum/Rated Discharge : 131.2 m3/s /127.4 m3/s
Number of Unit : 2
Install Capacity : Rated capacity: 127 MW, Maximum capacity: 140 MW
Peak Time : 6 hours
Primary Energy : 178.9 GWh
Secondary Energy : 323.6 GWh
Total Energy : 502.5 GWh
Turbine
Type : Vertical Shaft, Francis Turbine
Number: 2
Maximum/ Rated Output: 71,800 kW/64,700 kW
Revolving Speed : 300 min-1
Generator
Type : Three-phases, Synchronous Generator
Number: 2
Maximum/ Rated Output: 82,300 kVA/74,700 kVA per unit
Revolving Speed : 300 r/min
Frequency : 50 Hz
Rated Voltage : 13.2 kV
Power Factor : 0.85 lag
Switchyard
Type : GIS (Gas Insulated Switchyard)
Bus System: Double Buses
Number of Bays: 5
Voltage : 220 kV
Generation Facility : Rated/Maximum Effective Head :93 m/103.3 m
Environmental Discharge : 2.4 m3/s
Flow
Turbine Type : Horizontal Type, Francis Turbine
Number of Turbine/Generator: 1
Turbine Rated Output/ Maximum Output: 1,900 kW /2,100 kW
Generator Type : Horizontal Type, Three-phase Synchronous Generator
Rated Generator Capacity : 2,300 kVA
Distribution Transformer : 3-Phase Dry Type, Rated Capacity 2,305 kVA
Average Energy : During first 10 years; 14.0 GWh after 11th years; 13.0 GWh
220 kV Transmission Line
Conductor Type : 380 mm2 × ACSR (Bison)
Number of Circuit: 2
Voltage: 220 kV
Length : 36.43 km
Type of Transmission Tower : Steel lattice tower
Number of Steel Tower : 94
220 kV Bharatpur Substation
Number of Bays : Five (5) bays, of which Two (2) bays for transmission lines, Two (2) bays for interconnection to 132 kV substation, and One (1) bay for bus coupler
Inter bus Transformer: Capacity 83,300 kVA x 2 units Primary 220kV, Secondary 132 kV and Tertiary 11 kV
Voltage: 220 kV
Length : 36.43 km
Type of Transmission Tower : Steel lattice tower
Number of Steel Tower : 94