Super Madi Hydroelectric Project

Super-Madi-HeadworksSuper Madi Hydroelectric Project is located in Kaski Districts, Gandaki Zone of Western Development Region of Nepal. The project lies in the Namarjun and Parche Village Development Committees of Kaski District. The headworks is located at the foothill of Sikles village and the powerhouse is located just opposite of Sodha village. The project lies about 23 km north-east of Pokhara. At present there is about 16km long earthen road access towards the project from Pokhara City. An earthen road track has already reached to the Headrace Tunnel outlet which lies in the Namarjun Village Development Committee at the left bank of the Madi River.

This project is a simple Run-of-River scheme that utilizes the flow in Madi River. Madi River is one of the major tributaries of the Narayani River of the Gandaki basin after mixing with the Seti River. The proposed project has installed capacity of 44MW, design discharge of 18m3/sec and net head of 295m. A simple boulder riprap diversion weir across the Madi Khola diverts the water into the side intake. A gravel trap settles gravels coming through the six orifices of the intake and takes to the headpond through approach box culvert. Two underground settling basins are fed with the discharge by two inlet tunnels from the headpond. An outlet pond after the settling basins feed water into headrace tunnel. The headrace tunnel of length 5905m of finished diameter of 3.6~4.4m and steel penstock pipe of average diameter 2.6m and length 1381m feed water to the three units of vertical axis Pelton Turbines installed in the semi-surface powerhouse to generate 44000kW power. The water will then be discharge back into the Madi River through 281m long tailrace. An underground surge tank is provisioned at the end of the headrace tunnel. An access tunnel to the headworks, two Adit tunnels to access the underground settling basins, three Adit tunnels to access the headrace tunnel and a ventilation tunnel to reach the top of the underground surge tank are provisioned.Super-Madi-Powerhouse

The electricity generated from this plant will be connected to the Integrated Nepal Power System (INPS) at the Lekhnath Sub Station at Lekhanath Municipality near Pokhara City through 22km long 132kV single circuit transmission line. The total net energy production will be 243GWh annually.

Salient Features

Project Super Madi Hydroelectric Project
LOCATION
Development Region Western Development Region
Zone Gandaki
District Kaski
Intake Site Parch and Namarjun VDC
Powerhouse Area Namarjun VDC
General
Name of River Madi Khola
Nearest Town Pokhara, 23km
Type of Scheme Run-of-River
Gross Head 305m
Installed Capacity 44000kW
Hydrology
Catchment Area 284.1 km2
Mean Annual Discharge 30.29m3/s
Design Discharge 18m3/s
Probability of Exceedance 40.96%
Riparian Release 1.52m3/s (25% of minimum mean monthly flow)
Design Flood Discharge 1288 m3/s (100 Yr. Flood)
Diversion Weir
Type of Weir Free Overflow with Spillway
Total Length of Weir 60m
Height of overflow Weir from river bed 5m
Crest Elevation 1362masl
Design Flood Level 1368masl
Undersluice
Crest Elevation 1357m
Width 2 x 3m
Height 3m
Gate 2 Radial Gates
Side Intake
Type of Intake Side Intake (Orifice Type)
Size of Orifice (W x H) 2.4m x 1.6m, 6 Nos.
Intake Sill Level 1360m
Gravel Trap
No. of Chamber 1
Size 21m x 18.5~6m x 6m
Approach Box Culvert
Type Concrete Box Culvert
Length 53m
Size (W x H) 2 Units of 1.85~2.85m x 3m
Inlet Pond
Length 31m
Size (W x H) 12.4m x 4.95m
Normal Water Level 1361.25 masl
Inlet Tunnel
Shape Inverted-D
Numbers Two
Length 52m
Size (W x H) 3m x 3m
Underground Desanding Basin
No. of Chamber 2
Size 172m x 7.5m x 14.75m (parallel section 160m)
Particle Size to be settled 0.20mm @ 90% efficiency
Inlet Shaft
Type Circular
Height 13m
Size 3.6m dia. finish
Headrace Tunnel
Type Inverted-D Type Tunnel
Finish Diameter 3.6~4.4m
Length 5905m
Support Fully Concrete Lined (800m) Shotcrete Lined (5105m)
Surge Tank
Type Circular, underground
Height 37m
Finish diameter 9m dia.
Penstock Tunnel
Type Inverted-D Type Tunnel
Finish Diameter 2.8m circular penstock
Length 38m
Penstock
Material Exposed Steel Penstock
Diameter Avg 2.6m
Length 1381m
Thickness 12-32mm
Powerhouse
Type Semi-Surface
Dimension 52m (L) x 14m (B) x 28m (H)
Turbine Center Level 1055.5m
Number of Units Three
Tailrace Canal
Type Concrete Box Culvert
Length 160m
Size (W x H) 4m x 2.5m
Open canal length 122m
Size (W x H) 4m x 3m
Tail water outlet level 1047.90m
Turbine
Type Pelton
Number Three
Number of Nozzles Four
Arrangement of shaft Vertical
Design discharge per unit 6m³/sec
Rated Net Head 295.34m
Rated Efficiency 89.5%
Rated output capacity per unit 15540kW
Rated Speed 428.57 rpm
Generators
Number of units 3
Type Synchronous, 3 phase Salient pole, vertical shaft
Rated Output 17568 kVA
Rated Voltage 11 kV
Rated frequency 50 Hz
Power Factor 0.85
Rated Efficiency 96%
Transformer
Number unit 10 (9+1spare)
Type 1-phase, oil immersed
Installation outdoor
Rated capacity 6000 kVA
Rated H.V. (Secondary) 132 kV
Rated LV. (Primary) 11 kV
Cooling ONAN
Rated frequency 50 Hz
Rated Efficiency 99%
Transmission Line
Voltage Level 132kV
Length 22km
Connection NEA Sub-station at Lekhnath
Approach Road Connection
External Access Road Pokhara – Chasu, 18km (existing)
Project Access Road (to be constructed) Chasu- Powerhouse 5kmPowerhouse – Headworks 5.5km

Seti Khola – Surge Tank 4.2km

Energy
Net Saleable Annual Energy 243.125 GWh
Net Dry energy 37.856 GWh
Net Wet energy 205.269 GWh
Construction Period: 4 years (Main Project Works)

Source :   Himal Hydro & General Construction Ltd (website)