The UMCHEP is a run-of-the-river (RoR) type hydropower project with an installed capacity of 6.1 MW. However Power Purchase Agreement was done with Nepal Electricity Authority for 5.1 MW based on Q40 percentile exceedence. The UMCHEP is located at Mabu and Sulubung of Sandakpur Gaunpalika of Ilam district. The average annual energy generation of UMCHEP (5.1 MW) is 30.297 GWH.
The electricity generated from both the plants have been evacuated through 18.5 kM Mabu-Ilam 132 kV transmission line connected to National Grid of NEA at Godak Substation.
The total cost of both the plants including 132 kV transmission line is NRs. 3380 Million.
Headworks of Upper Mai C HEP
Powerhouse of Upper Mai C HEP
Switchyard of Upper Mai C HEP
| A. Hydrology | |
| Catchment area at Intake: | 70.00 km2 |
| Design discharge : | 4.62 m3/s |
| Gross head: | 161.0 m |
| Net head @ full discharge: | 155.25 m |
| Installed capacity: | 6.1 MW |
| B. Headworks | |
| Diversion weir | |
| Type: | Free Overflow type |
| Crest elevation: | 1245.21 m above masl |
| Height of weir: | 3.62 m |
| Crest length: | 11.0 m |
| Intake | |
| Type: | Bottom type |
| Size: | 1.5 m wide X 1.2 m high X 9 m length |
| Sill elevation: | 1243.61 m above masl |
| Sediment Trap | |
| Type: | Bottom trench type |
| Size: | 0.62 m width X 9.0 m X 1.08 avg height |
| Flushing Gallery | |
| Type: | Culvert type |
| Size: | 23.7 m long X 0.6 m wide X 0.8 m height |
| Approach Canal | |
| Type: | Concrete rectangular |
| Size: | 1.5 m wide X 2.5 m height X 5.0 m length |
| Settling Basin: | |
| Type: | Concrete Hooper base |
| Number of chambers: | 2 |
| Size (parallel section): | 43.0 m long X 4.0 m wide X 3.15 m height |
| Normal water level: | 1244.31 m above masl |
| Collection Pond: | |
| Size: | 14.43m long X 10.4m wide X 3.53m height |
| Normal water level: | 1243.51 m above masl |
| C. Waterways | |
| Mai Khola Crossing: | |
| Length of siphon: | 62.0 m |
| Size: | 1950 mm internal dia 10 mm thick pipe |
| Headrace pipe | |
| Total length: | 396.0 m (including river crossing) |
| Internal diameter: | 1950 mm |
| Type: | |
| Headrace tunnel | |
| Shape: | Inverted D-shape |
| Length: | 976.0 m |
| Cross-section: | 2.0 m wide x 2.0 m high |
| Surge shaft | |
| Type: | Surface |
| Internal diameter: | 4.0 m |
| Height: | 17.5 m |
| Maximum surge level: | 1248.74 m |
| Minimum surge level: | 1238.12 m |
| Rock Trap | |
| Length: | 6.0 m |
| Width: | 2.0 m |
| Depth: | 1.0 m |
| Type: | Surface/buried |
| Length: | 953.0 m |
| Internal diameter: | 1.48 m and 1.4 m |
| Thickness: | 10, 12, 14 mm |
| Anchor blocks/Saddle support: | 18 Nos / 103 Nos |
| D. Powerhouse and tailrace | |
| Powerhouse | |
| Type: | Surface |
| Size: | 24.00 m x 6.75 m x 18.05 m |
| Floor elevation: | 1080.00 m above masl |
| Tailrace | |
| Culvert: | Box culvert |
| Culvert size: | 41.0 m x 3.2 m x 1.2 m |
| Invert Level: | 1077.40 masl |
| E. Mechanical and electrical | |
| Turbine | |
| Type: | Francis horizontal axis |
| Rated net head: | 154.30 m |
| Rated discharge: | 2.32 m3/s |
| Rated output: | 3050 kW |
| No. of units: | Two |
| Axis level: | 1081.05 m above masl |
| Generator | |
| Type: | Synchronous |
| Number of Unit: | Two |
| Capacity: | 3800 KVA |
| Voltage: | 6.6 kV |
| Power factor: | 0.80 |
| Frequency: | 50 Hz |
| Excitation system: | Brushless |
| Efficiency: | 96.0% |
| Transformer | |
| Type: | Three phase |
| Rating: | 8 MVA |
| Voltage ratio: | 6.6 kV/132 kV |
| Frequency: | 50 Hz |
| Efficiency: | 99% |
| F. Transmission Line | Combined with UMHEP |
| G. Energy Generation (5.1 MW) | |
| Dry season energy: | 5.126 GWh |
| Wet season energy: | 25.170 GWh |
| Total Energy: | 30.297 GWh |