General

Name of Project

:

Seti Nadi Hydroelectric Project

Name of River

:

Seti Nadi

Type of Scheme

:

Run of River

Project Location

Province No.

:

Gandaki (Province No. 04)

District

:

Kaski

Project Area

:

Machhapuchre Rural Municipality & Pokhara-Lekhnath Metropolitan City

Geographical Co-ordinates

Latitude

:

28° 18′ 40″ N to 28° 22′ 12″ N

Longitude

:

83° 57′ 15″ E to 83° 58′ 30″ E

Organization

Developer

:

Vision Lumbini Urja Company Limited.

Consultant

:

JV of Hydro-Consult Engineering Ltd. & Building Design Authority (p) Ltd.

Hydrology

River Name

:

Seti Nadi

Catchment Area (At Intake)

:

253.65 km²

Catchment Area (At Powerhouse)

:

332.53 km²

River Type

:

Rain fed, Perennial River

Design Discharge(44.50 % Exceedance)

:

18 m3/s

Riparian Release

:

0.52 m3/sec

Design Flood Discharge at Intake

:

745.05 m³/s (100 year return period)

Design Flood Discharge at Powerhouse

:

968.85 m³/s (100 year return period)

Geology

Regional Geology

:

Lesser Himalaya Zone

Major rocks in Headworks

:

Conglomerate  and alluvial deposits

Major rocks in Waterways

:

Schist, Gneiss and Phyllite

Major rocks in Powerhouse

:

Alluvial Terrace

Headworks  Structures

Diversion Weir

Concrete weir Ogee type

Crest Level of Weir

:

1277.00 masl

Length of Weir

:

30.0 m

Type of Weir

:

Free overflow, concrete weir

Height of Weir

:

5.0 m from river bed

Bed level of Weir

:

1272.00 masl

Operating Platform Level

:

1282.75 masl

Boulder Lined Weir

Length

:

50.0 m

Weir Crest Level

:

1280.45 masl

U/S Slope

:

1 in 2.80

D/S Slope

:

1 in 5.50

Diversion During Construction

Construction flood

:

31 m3/s (1in 20 year dry season flood)

Intake

Type

:

Side Intake with Orifice

Orifice Size

:

3.80 m (W) x 2.50 m (H)

No. of Orifice

:

3 (Three)

Invert Level

:

1274.00 masl

Sill Level

:

1276.50 masl

Trash Rack

Type

:

Coarse Trash Rack

Rack Dimension

:

16 mm thick bar @ 100 mm c/c spacing        

 Under Sluice

No. of bay

:

2 (Two)

Design Discharge

:

12% of flood discharge (89.40 m³/sec)

Size

:

2.5 m x 2.5 m

Under Sluice Bed

:

1272.00 masl

 Gravel Trap

No of Bay

:

2 (Two)

Size

:

8.50 m (L) x 6.65 (B) x 6.83 m (H)

Bed load size to be trapped

:

Larger than 5 mm

Flushing system

:

Continuous during monsoon

Flushing Canal

:

33.75 m (L) 1.50 m (W) x 1.80 m (H)

Approach Culvert

Type

:

Free flow closed culvert

Length of the canal                   

:

443.50 m

Size of canal                                            

:

3.80 m x 2.55 m

Number of Canal                                   

:

1

Bed Slope

:

1 in 600

Settling Basin

Type

:

Intermittent Gravity Flushing

No of Bays

:

3 (Three)

Particle Size to Settle

:

≥ 0.2 mm

Inlet Transition Length

:

24.50 m

Main Settling Zone Length

:

65.0 m

Width

:

7.45 m at bottom and varying at top

Depth

:

9.60 m – 11.05 m

Flushing system

:

Hydraulic Flushing

Flushing Opening Size

:

1.0 m x 1.8 m, RCC Canal

Longitudinal Slope

:

1 in 40

Headpond

Depth

:

9.52 m

Bed Level

:

1268.19 masl

Normal Water Level

:

1276.15 masl

Spillway Type

:

Sharp Crested vertical fall type

Spillway Crest Elevation                          

:

1276.75 masl

Length of Spillway

:

44.45 m

Waterways

Headrace Pipe

Material

:

IS 2062: 2011 E350 BR

Length

:

6077.45 (Outlet of headpond toT-Junction )

Internal Diameter

:

2.80 m, 2.65 m  and 2.50 m

Shell Thickness

:

10 mm-22 mm

No. of Anchor Blocks

:

80 (including T- Junction )

Connection Pipe to Surge Tank

Material

:

IS 2062: 2011 E350 BR

Length

:

677.70 m (From T-Junction to Surge chamber )

Internal Diameter

:

2.40 m

Shell Thickness

:

12-22 mm

No. of Anchor Blocks

:

12

Surge Pipe

Material specification

:

IS 2062: 2011 E350 BR

Type

:

Surge Pipe with upsurge and downsurge chamber

Diameter

:

3.0 m

Length

:

122.20 m

Upsurge Chamber

:

3 m dia. & 45 m Long (Trident Shape)

Downsurge Chambers

:

3 m dia. & 70 m Long/ 3 m dia. & 60 m Long

No. of Anchor Block

: 

13

Thickness

: 

12 mm

Penstock Pipe

Material

:

IS 2062: 2011 E350 BR

Length

:

302.05 m(From T-Junction to Bifurcation)

Internal Diameter

:

2.50 m

Shell Thickness

:

22-25 mm

No. of Anchor Blocks

:

5

Bifurcation

Material

:

IS 2062: 2011 E350 BR

Length

:

30 m(Two Branch of 15m each)

Internal Diameter at inlet

:

2.50 m

Internal diameter at outlet

:

1.77 m

Shell Thickness

:

20 mm

Powerhouse

Type

:

Sub-Surface

Size

:

42.10 m x 15.15 m

Turbine Type

:

Horizontal Axis Francis

Turbine Axis Level

:

EL. 1093.30 masl

No of Units

:

2

Tailrace Culvert

Shape

:

Rectangular

Size of Tailrace Culvert

:

3.50 m x 2.50 m

Length of Tailrace Culvert

:

127.0 m

Tailrace outlet

:

Seti Nadi

Bed Slope

:

1in 450

Tail Water Level

:

EL. 1093.50 masl

Turbine

Type

:

Horizontal Axis Francis

Number of Unit

:

2

Rated Output Capacity per unit

:

13.500 MW

Turbine Axis Level

:

1093.30 m

Rated Net Head

:

161.35m

Discharge per Unit

:

9.00 m³/sec

Efficiency

:

94.60%

Governor

Type

:

Digital Electronic with PID type

Adjustment for Speed Drop

:

Adjustable to any degree between zero and 100% 

Generator

Type

:

Three Phase synchronous generator

Capacity

:

15.4 MVA

Number of units

:

2 (Two)

Power factor

:

0.85

Generating Output Voltage

:

11 kV

Frequency

:

50 Hz

Excitation System

:

Brushless

Efficiency

:

≥ 97.0%

Synchronous Speed

:

600 RPM

Transformer 

Type

:

Outdoor, oil immersed

Number of Phases

:

Three(3)

Number of unit

:

Two(2)

Rating

:

16.0 MVA

Rated Voltage

:

11 kV for Primary side & 132 kV for Secondary side

Frequency

:

50 Hz

Vector Group Reference

:

YNd11

Efficiency

:

99%

Switchyard 

Type

:

Outdoor

Size

:

45.10 m x 38.10 m

Power and Energy

Gross Head

:

183.50 m

Maximum Net Head

:

182.00 m

Minimum Net Head

:

161.35 m

Rated Net Head

:

161.35 m

Installed Capacity

:

25000 kW

Dry Season Energy (PPA)

:

46.54 GWh

Wet Season energy(PPA)

:

101.54 GWh

Total Energy(PPA)

:

148.09 GWh

Transmission Line & Substation      

Length

:

5 km (Approx.)

From

:

Powerhouse

To

:

Lahachowk Substation

Type

:

132 kV Single Circuit