Salient Features

Project Location:
Province
1 (Former Eastern Development Region)
District
Taplejung
Municipality / Rural Municipality
Phaktanglung Rural Municipality, ward No. 1,2,3,4,5,6 (Former Tapethok, Lelep and Linkhim VDCs.) Phungling Municipality, ward No. 10 (Former Phurumbu VDC)
Nearest Town
Phungling
Headworks Area
Tapethok Village, Phaktanglung Rural Municipality
Powerhouse Area
Sisne Village, Phungling Municipality
Geographical Co-ordinates:
Latitude
27° 25’ 19” N to 27° 30’ 45” N
Longitude
87° 41’ 40” E to 87° 48’ 03” E
General:
Name of River
Tamor
Type of Scheme
Peaking Run-of-River
Gross Head
450 m
Net Head
433.42 m
Installed Capacity
285 MW
Installed Capacity for PPA
255.28 MW
Hydrology:
Catchment Area at Intake site
1850 km2
Average Flow
115 m3/s (minimum mean monthly flow 18 m3/s)
Design Flow
69 m3/s (42.4% exceedance flow)
Design Flood (100 year return period)
2085 m3/s
Diversion Dam:
Type
Concrete Gravity, with overflow and non- overflow sections
Crest Elevation
1364.00 m amsl
Maximum height
12.5 m (from the Original ground level)
Length
53 m (overflow section), 117 m (overall length)
Barrage Gates
4 Nos. 12.5 m wide each at elevation 1351.50 m
Undersluice:
Type
Rectangular Orifice
No. of Bays
2
Invert Elevation
1346.00 m amsl
Size (B X H)
4 m x 7 m
Intake:
Type
Side Intake
Number of Orifices
4
Invert Elevation of Orifice
1353.25 m amsl
Size (B X H)
6.4 m x 5 m
Gravel Trap:
Type
Surface, Hopper Shaped
Particle size to be settled
≥ 5 mm
Number of Chambers
2
Size (L x B)
25 m x 14.8 m
Approach Culvert:
 
Type
Rectangular Shape
Number of Chambers
3
Size (B x H)
6 m x 3 m
Length
83.75 m
Longitudinal bed slope
1:900
Settling Basin:
Type
Surface, Hopper Shaped
Particle size to be settled
≥ 0.15 mm
Number of bay
3
Length
170 m, additional 153 m length in inlet transition and 24 m in outlet transition
Dimension (B X H)
24 m x 15.4 m (each)
Longitudinal bed slope
1 : 100
Headpond:
Type
Surface Structure
Storage Capacity
0.8 Mm3
Average Dimensions (L x B)
610 m x 175 m
Maximum Height of right embankment
19 m
Bypass Culvert:
Type
Rectangular, RCC
No. of Bays
2
Dimensions (Width x Height)
3 m x 6 m (each bay)
Length
674 m
Headrace Tunnel:
Type
Pressure Flow
Shape
Modified horse-shoe
Length
8730 m
Excavation Diameter
7.3 m
Tunnel inlet invert elevation
1325 m amsl
Longitudinal slope
1:1000
Support System
Concrete Lining, Rock bolts and Shotcrete
Adit Tunnels:
No. of Adit Tunnels
5
Shape
Inverted-D
Diameter
4.5 m
Lengths
872 m, 1087 m, 806 m, 931 m and 627 m
 
Surge Shaft:
Type
Vertical, Circular Section
Diameter
20 m
Height
58 m
Inclined Shaft:
Type
Concrete encased steel pipe inside circular tunnel
Tunnel Diameter
5 m
Pipe Diameter
4 m
Length
631 m
Pipe thickness
16 mm to 63 mm
Powerhouse:
Type
Underground
Dimensions (L x B)
119.3 m x 38.5 m
Erection Bay Level
912.90 m amsl
Turbine Axis Level
900 m amsl
Tailrace Tunnel:
Type
Rectangular Free Flow Tunnel
Size (B x H)
6.6 m x 4.8 m
Length
1016 m
Tailwater Level at outlet
895.30 m amsl
Turbine:
Type
Vertical Axis Pelton Turbine
Number of Unit
5
Turbine Capacity per Unit
53 MW
Discharge per Unit
14.6 m3/s
Turbine efficiency
91%
Generator:
Type
Vertical
Number of Unit
5
Rated Output
60 MVA
Generation Voltage
11 kV
Frequency
50 Hz
Power Factor
0.85
Generator efficiency
97%
Transformers:
Type
Single-Phase, Oil immersed
Number of Units
15+1
Frequency
50 Hz
Rating
20 MVA
Voltage Ratio
11kV / 220 kV
Transformer Efficiency
99.00%
Transmission Line:
Voltage Level
220 kV
Length
15 km (5 km up to Middle Tamor Hydropower Project Switchyard)
Connection Point
Dhungesanghu Substation
Power and Energy:
Installed Capacity
285 MW
Dry energy
219.61 GWh
Wet energy
1349.93 GWh
Annual Net Energy Output
1569.54 GWh