1.1 General Arrangement
It is a Run-of-River type of project utilizing water of Dordi Khola and collection of Purmu at the Adit site. The discharge of Dordi Khola shall be diverted to the left side of the river towards gravel trap. Course material up to 20mm shall be settled in Gravel Trap.
There will be inlet portal towards underground desander for the settlement of fine sediment of size up to 0.15mm. The headrace tunnel of 4.8km follows to underground surgetank at the end of horizontal portion after Taje Village on the ridge before Lodo Khola.
There are two intermediate adit at Prumu Khola and Kyame Khola. Prumu Khola discharge will be collected in headrace tunnel from the same access tunnel near purmu khola. After the surge tank, there will be underground inclined penstock shaft which directly delivers flow to surface power house having vertical axis Pelton turbines. The discharge will be release back to Dordi Khola near confluence with Lodo khola from tailrace canal.
There will be generators, control panels, power transformers, 132kV switchyard and single circuit transmission line to proposed Dordi Corridor Hub at Kirtipur which is further connected to Udipur 220/132kV substation for power evacuation to national grid. The company has signed connection agreement for the evacuation of the power through Udipur substation after 2017.
1.2 Salient Features
The following is the brief salient feature of Super Dordi Hydropower Project-Kha.
| SN | Particular | Salient Features |
| 1 | Project Location | |
| Location of Project SIte | Dordi Gau Palika, Lamjung District, Gandaki Province | |
| Longitudes | 84° 31 00” E and 84° 34 15” E | |
| Latitudes | 28°16’ 20” N and 28° 18’ 43” N | |
| 2 | Project Type | |
| Type of Scheme | Run of River (RoR) | |
| Installed Capacity | 54.0 MW + 10% Continuous Overload (CoL) i.e 59.4 MW- | |
| Total Continuous Capacity | ||
| Gross head | 637.55 m | |
| Design Discharge | 9.9 m3/sec at Q 40% | |
| Energy After outage + loss | 3 14.983 GWh | |
| 3 | Hydrology | |
| Catchment Area | 142.45 sq km | |
| Average Percipitation | 2035 mm/year | |
| 100 years Design Flood (HW) | 300 m3/sec | |
| 100 years Design Flood (PH) | 362 m3/sec | |
| Design Discharge | 9.30 m3/sec (Q 40%) (Dordi HW) and 0.60 m3/sec (Q 40%) (Purmu) and total is 9.90 m3/sec (Q 40%) | |
| 4 | Headworks | |
| Diversion Structure | Broad Crest Free flow gravity weir | |
| Length of weir | 18.5 m | |
| Weir crest elevation | EL 1887.6 msl | |
| Height of weir | 17.5m from Foundation with Grouting | |
| Crest of Sluice | EL 1884.00 msl | |
| Size of Sluice gates (bxh) | 3.0 m× 3.0 mx 1 nos | |
| Intake Type | Side Intakes | |
| Size of opening | 3.0 m x 1.5 m – 3 nos | |
| Crest elevation of Intake | El 1885.50 msl | |
| 5 | Gravel Trap | |
| Type | D-Shaped Inside Inlet Tunnel | |
| Particle Size to be settled | 20mm | |
| Length of Gravel Trap | 36 m length | |
| Size (Width X Depth) | 4.0mx (2.3-4.0)m | |
| Bed Slope | 1:20(Settling Part) | |
| 6. | Connecting Tunnel | |
| Tunnel Length | 257.67 m from Gravel Trap to Desander | |
| Type | Inverted “D” Shape, Low Pressure Full Flow | |
| Size of Tunnel | 4.2m (width) x 3.5 m (H) | |
| Nos. of bend | 3 nos. | |
| 7 | Desander Basin | |
| Type | Length=90 m x 2 Nos = 180 m Underground Dufour Double Chamber Continuous Flushing Type | |
| Particle Size to be settled | 0.15mm | |
| Size of Desander | 2 Chamber each of 10.6m X 8.6m x 100m length | |
| Bed Slope | 1:50 | |
| Flushing Channel Size | 1.2 x 0.5 to 2.5 m | |
| 8.a) | Headrace Tunnel (HRT) | |
| Tunnel Length after Desander | 5158.66 m | |
| Type | Inverted “D” Shape, Low Pressure Concrete and Shotcrete Lined | |
| Size of Tunnel | 2.8m Finished Diameter | |
| Average tunnel slope | 0.25 | |
| Nos. of bend | 7 no. | |
| Rock Trap | 2.8mX2.8m; 25 m length | |
| Nitches | 3mx3mx 10m in length each 250 m | |
| 8.b) | Purmu Adit for Headrace Tunnel | |
| Type | Inverted “D” Type, Shotcrete lined | |
| Size of Tunnel | 2.8 m X 2.8 m | |
| Length | 294 m | |
| 8.c) | Kyame Adit for Headrace Tunnel | |
| Type | Inverted “D” Type, Shotcrete lined | |
| Size of Tunnel | 3.5 m X 3.5 m | |
| Length | 94 m | |
| 8 | Surge Shaft | |
| Type | Cylindrical Restricted orifice | |
| Construction | Concrete Lined underground | |
| Dia of Tank | 6.0m | |
| Dia Of orifice | 2.0m | |
| Total Height | 49.2m | |
| Invert Level | EL 1859.75m | |
| Top Level | EL 1908.92m | |
| Static level | EL 1387.60m | |
| Upper Surge Level | EL 1905.42m | |
| Operating Level | EL 1875.75m | |
| Down Surge Level | EL 1867.05m | |
| 9 | Penstock Shaft | |
| Type | Steel Lined Drop and Horizontal Shaft | |
| Length | 1048m (Including Branches 45m) | |
| Pipe Material | High Strength Steel IS 2062-B E450 | |
| Size of Pipe | 2.2m dia to 1.8m dia 10-42mm thick | |
| Number of Bends in Shaft | 5 Including Y | |
| Number of Anchor Blocks | 12 nos. | |
| Type of Adits | Inverted “D” Type, Shotcrete lined | |
| Size of Adits | 35 m X 3.5 m. 346 m | |
| 10 | Powerhouse | |
| Type | Underground Power House Cavern | |
| PH dimension | 51.3 m (L) x 15 (B) ×29.5 m (H) | |
| Height / Width of PH building | 30.0 m / 15.0 m | |
| CL of Runner | EL 1250. 1 m | |
| 11 | Tail race Tunnel | |
| Type | Inverted “D” Shaped, Shotcrete lined Free Flow Tunnel | |
| Size (wxh) | 3.0 m x 3 5 m | |
| Length | 423 m (Tailrace Tunnel) including branches | |
| 12 | Turbine | |
| Number of Units | 2 | |
| Type of Turbine | 4 Jet Pelton, Vertical Axis, 600 RPM | |
| Shaft Arrangement | Vertical | |
| Rated discharge for each turbine | 4.95+10% CoLm3/s | |
| Rated Head | 625.8m | |
| Rated Output for each unit | 28000 kW+ 10% COL | |
| Rated Efficiency | 91.50% | |
| Speed Governor | Electro-Hydraulic (Electronics) | |
| 13 | Generators | |
| No of units | 2 | |
| Generator Type | 3 ph AC Vertical Synchronous, 50Hz | |
| Excitation | Brushless excitation | |
| Rated Voltage | 11.0 kV | |
| Power Factor | 0.85 | |
| Rated Efficiency | 98.00% | |
| Rated Output | 31.765MVA + 10% CoL | |
| Rated Frequency | 50 Hz | |
| 14 | Power Transformer | |
| Type | Step up power transformer | |
| Capacity | 25MVAx 3 Nos, Single Phase | |
| No of Units | 4 Nos x 1 ph, 50 Hz (including I Spare) | |
| Type of Cooling | ONAN(Oil Natural Air Natural) | |
| Primary (LV Side) | 11 kV | |
| Secondary (HV Side) | 132 kV | |
| Connection | Delta/Star △/Y | |
| Overload Capacity | 120% for 4 Hrs. | |
| 15 | Station Supply Transformer | |
| Type | Indoor type | |
| Capacity | 250 kV A each unit | |
| Number of Unit | 2 | |
| Type of Cooling | Dry Type | |
| Voltage Ratio | 11.0/0.4, 0.23 kV | |
| Connection /Vector Group | Dyn11 | |
| 16 | Transmission Line | |
| Transmission Length | 6 km | |
| Transmission Voltage | 132 kV | |
| Type of Circuit | Double Circuit Tower | |
| Proposed Interconnection Point | NEA Interconnection Substation, Kirtipur | |
| Line Conductor | Bear | |
| 17 | Power and Energy | |
| Installed Capacity | 54 MW (formerly 49.6 MW) | |
| Deemed Energy (Contract Energy in PPA) | 314.983 GWh | |
| Dry Season Energy | 53.03 GWh | |
| Wet Season Energy | 261 95GWh |
1.3 Project Execution Parties
1.4 Capacity Enhancement
