Super Madi Hydroelectric Project

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    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)