• Task: Desk study,Licensing and Feasibility study,preparation of Tender document, Detailed engineering design, Construciton Supervision

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• Capacity: 22 MW

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• Status: Completed

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1. General
Project	Mai Hydropower Project (22 MW)
Purpose of the Project	To supply for domestic use of connecting to national grid
Location	Danabari and Chisapani VDC,Illam District , Eastern Development Region of Nepal
2. Hydrology
Catchment area	589.0 km2
Mean Annual Dishcharge	31.77m3/sec
Design Discharge (at 40%PoE)	23.40 m3/s
Riparian Release	0.72 m3/s
Design flood Discharge	2070 m3/s (100Yr. Flood)
Average Annual Precipitation	2500mm
3. Diversion Weir
Type of Weir	Concrete gravity dam
Length of Weir	86.00m
Max. Height of Weir	11.00m
Crest Elevation	EL.321.10 m
4. Intake Structure
Type	Frontal Intake, submerged
Size	2.55 m x 6.00 m
Nos	3 (Three)
Crest elevation of Orifice	EL. 318.50 m
5. Undersluice Structure
Type	Over-flow weir with undersluice
Crest Elevation	2.00 m x 4.00 m
Nos	3 (Three)
Crest elevation of undersluice	EL. 314.50 m
6. Intake Canal
Type	Rectangular, RCC open type
Maximum height	7.50 m
Average Width	4.0 m
Side Spillway crest elevation	EL. 321 m
Spillway length	11.90 m
7. Approach Culvert
Type	RCC pressurized conduit
Nos	2 (Two)
Length
	80.00 m
Size (Width x Depth)	2.00 m x 2.50 m
8. Decending Basin
Type	Convensional flushing
No of Bays	4 (Four)
Dimention (L x B x H)	75.00 m x 19.50 m x 5.85 m
Practicle Size to be settled	0.2 mm
9. Headrace culvert
Type	RCC pressurized conduit
Length	1072 m
Size (Width x Depth)	3.5 m x 3.30 m
Bed Slope	1.083333333
10. Headrace Tunnel
Type	Inverted D-Shaped
Length	2192.0 m (including 66 m after surge-tank)
Tunnel area	13.10 m2/s
11. Surge Tank
Type	Vertical, circular section
Diameter	8.00 m
Height	35 m
12. Penstock
Type	Exposed on surface
Internal Diameter	2.60 m
Length	316.38 m
Max Steel Thickness	25 mm
Nos of Suppports	51
Nos of Anchor Blocks	8
13. Powerhouse
Type	Semi-surface
Size	37 m x 22 m
Height	9.75 m
P/H Floor Level	EL.205 m
14. Tailrace Culvert
Type	Rectangular, RCC
Length	229.49 m
Size	3.50 m x 3.30 m
Tail Water Level	EL. 199.00 m
15. Turbine
Type	Vertical Axis Francis
Number	3 (Three)
Rated Output Capacity	3*7600kW
Efficiency	92.50%
16. Governor
Type	Electronic with PID Control
Adjustment for Speed Drop	Between 0 to 5%
17. Generator
Type	Synchronous 3 Phase
Rated output Capacity per Unit	9170 KVA
Nos of Units	3 (Three)
Power Factor	0.8
Voltage	6.3 kV
Frequency	50 Hz
Excitation System	Brushless
Efficiency	96.50%
18. Transformer
Type	Three phase
Rated Capacity	10,000 KVA and 20,000 KVA
Voltage Ratio	6.3 / 132 kV
Efficiency	99.00%
19. Transmission Line
Voltage Level	132 kV
Length	11.60 Km
Conductor	ACSR “WOLF”
From	Powerhouse
To	Proposed NEA Sub-Station at Godak, Ilam
20. Project Cost Estimate
Total Cost of the Project	3097.50 Millions NRs
21. Construction Period
52 Months after signing PPA of 15.6MW
22. Other:
Facilites for Black Start, Off Grid Mode Operaion or Local Grid Mode Operation shall be incorporated in the Project.