|
PROJECT LOCATION |
|
State |
Sikkim |
|
District |
West |
|
Stream |
Rathang Chu River |
|
Location of Power House (nearest village) |
Tashiding |
|
Latitude |
270 20’28” N |
|
Longitude |
880 13’59” E |
|
|
HYDROLOGY |
|
Catchment area at Barrage Site |
553
sq. km |
|
Average Annual precipitation in snow fed catchment |
1250 mm |
|
Average Annual precipitation in rain fed catchment |
2500 mm
|
|
Average Annual Inflow |
2578 mm
|
|
Flood Discharge for River Diversion (~Q25) Non-Monsoon |
175
Cumec |
|
Flood Discharge with return Period T=100 years |
1650 Cumec |
|
Standard Project Flood Discharge (SPF) (~Q 500) |
2000 Cumec
|
|
Probable
Maximum Flood Discharge (PMF) |
2690 Cumec |
RESERVOIR |
|
Pond Level (FRL) |
El. 910.00 m |
|
Minimum Draw down Level |
El.905.00 m |
|
Maximum Water Level |
El.914.00 m |
|
Pondage above MDDL (Diurnal storage) |
0.051 M cum |
|
Submergence area at FRL |
1.33 ha |
|
Stretch of Reservoir
|
0.27 km |
|
|
DIVERSION TUNNEL |
|
Shape & Size |
Horse- shoe shaped, 4.5 m
|
|
Length |
167 m
|
|
Flow Velocity |
10.42 m/sec |
|
Diversion Flood |
175 cumec |
|
Lining Thickness (PCC) |
150 mm |
|
|
|
|
Type |
Barrage |
|
Top elevation
of barrage |
El.917.0 m |
|
Height of
barrage above crest level |
12 m
|
|
Length of
barrage between abutments |
42.50 m |
|
River bed level
(deepest) |
896.50 m |
|
Design flood |
1650 cumec |
BARRAGE BAY |
|
Crest elevation |
El. 898.00 m |
|
Number |
4 |
|
Width of each
bay |
6.5 m |
|
Total floor
length |
138 m |
|
Gates |
|
|
Type |
Fixed wheel
type Vertical Lift |
|
No. & Size |
Four, 6.5 m (W)
x 9.0 m (H) |
Under sluice Gates
|
|
Crest elevation
|
El.896.50
m |
|
Number |
1 |
|
Width of each
bay |
6.5 m |
|
Total floor
length |
138 m |
|
Gate |
|
|
Type |
Fixed wheel
type Vertical Lift |
|
No & Size |
One, 6.5 m(W) x
9.0 m (H) |
|
|
Intake |
|
Location |
On right bank, 7.3 m upstream of barrage axis
|
|
Total width
between abutments |
24m
|
|
Trash Rack
Structure |
Inclined |
|
Size of opening for trash rack |
5 Nos. 4m (W)
|
|
Crest Level of
Trash rack |
EL.900.40 m |
|
Size of Intake
opening |
4.3 m(W) x 4.5 m(H) |
|
Invert level of Intake at entry |
EL.896.85 m
|
|
Design Discharge |
50.76 Cumec |
|
Velocity of flow through Trashracks |
0.75 m/sec |
|
No., Type & Dimension of Gates |
One, Vertical lift gate, 4.3 m(W) x 4.5 m (H) |
|
|
|
HEADRACE TUNNEL-HRT |
|
Shape & Size |
Horse- shoe shaped, 4.5 m
|
|
Length |
5.437 km
|
|
Flow Velocity
at Design Discharge |
3.02 m/sec |
|
Design Discharge |
50.76 cumec |
|
Lining Thickness (PCC) |
200-300 mm |
|
|
|
Adit To
HRT |
|
Location |
About 1.59 km d/s of Barrage axis |
|
Shape & Size |
D-shaped, 4.5m |
|
Length |
236 m |
|
Level |
El. 875.00m |
|
|
|
SURGE SHAFT |
|
Vertical Shaft |
Restricted Orifice Type
|
|
Internal Diameter |
8.5 m |
|
Height of shaft |
61.05 m |
|
Concrete lining thickness |
Varying from 300 mm to 600 mm |
|
Lining Type |
RCC Lining |
|
Vertical Lift Gate size |
3.5 m (W) x 4.5 m (H) |
|
Top of Surge shaft |
El. 936.00 m |
|
Bottom of Surge shaft |
El. 877.00 m |
|
Max. Surge level |
El. 933.20 m |
|
Min. Surge level |
El. 879.35 m |
|
Orifice dia. |
2.00 m |
|
|
|
Adit to HRT & Surge Shaft Bottom |
Shape & Size
|
D-Shaped, 4.5m
|
|
Entry Sill Level |
EL.869.00 m |
|
Length |
89 m |
|
|
|
PRESSURE TUNNEL/PENSTOCK |
|
Total Length upto Bifurcation |
441.53 m |
|
Internal
Diameter |
3.5 m |
|
Horizontal length from Surge Shaft to portal
|
63.28 m |
|
Inclined Penstock Length from portal to Bifurcation point |
378.25 m |
|
Number of anchor blocks |
5 |
|
Bifurcation Point |
20 m upstream of PH |
|
No. of Branch after Bifurcation |
2 |
|
Diameter after Bifurcation |
2.5 m |
|
Branch penstock length |
25 m & 33 m |
|
Steel liner thickness |
16 mm to 32 mm |
|
Grade of Steel lining |
ASTM 537 Class-II |
|
|
POWERHOUSE |
|
Type |
Surface Powerhouse |
|
Size |
50.5 m(L) x 33.5 m(W) x 44.1 m(H) |
|
Number of units |
Two (2) |
|
Rated Discharge per unit |
25.38 Cumec |
|
Turbine Speed |
428.57 rpm |
|
Min. Tail Water Level |
EL.686.6 m |
|
Normal Tail Water Level |
EL. 688.5 m |
|
Gross Head (monsoon period) |
EL. 221.5 m |
|
Net Rated Head |
208.33 m |
|
Installed Capacity |
2x 48.5 MW |
|
Inlet Valve Type |
Spherical Valve |
|
Number |
2 |
|
Turbine Axis Elevation |
EL. 681.60 m |
|
Generator type
|
Suspended |
|
Nominal Speed |
428.57 rpm |
|
Voltage / Frequency |
11 KV /50 Hz |
|
Power Factor |
0.9 |
|
No. & Size of Draft Tube Gates |
Two nos., 5.14 m (W) x 4.03 (H)
|
|
|
|
TRANSFORMER |
|
Type and
capacity |
Three
phase,11KV/220KV, 60 MVA, OFWF |
|
Location |
Outdoor on
right bank of the river |
|
Number
|
2 |
|
|
|
|
TRAILRACE CHANNEL |
|
Type |
Open Channel
|
|
Length
(Including tail pool) |
78.5 m |
|
Bed Slope (Tail
Pool) |
1:4 |
|
Nominal
Discharge |
50.76 Cumec |
|
River Bed
Elevation |
EL.686.00 m |
|
|
|
SWITCHYARD |
|
Type |
Outdoor |
|
Size |
42 m x 53 m
|
|
Location of
Switchyard |
Upstream of PH
on right bank at El. 710 m |
|
Bus bar
Voltage
|
220KV |
|
|
TRANSMISSION
LINE |
|
Type |
Switch yard to Melling
pooling station, 220 KV single circuit |
|
Length |
About 27 km |
|
|
|
|
|
ESTIMATED COST |
|
Civil Works (Including gates & hoists) |
Rs 204.21 Crore |
|
E&M Works
(Including cost of Transmission line to pooling station) |
Rs. 156.83
Crore |
|
Total Basic
Cost |
Rs. 361.04
Crore |
|
Escalation
during construction |
Rs. 34.79
Crore |
|
Interest
during Construction |
Rs. 70.12
Crore |
|
Total
(Generation Works) |
Rs. 465.95
Crore |
|
Cost per MW
installed |
Rs. 4.80
Crore |
|
|
|
POWER BENEFITS |
|
Annual Energy
Generation including 10% overloading utilizing high inflow
(90% Dependable Year) |
450.04GWh
|
|
Annual Energy
Generation in Average Year including 10% overloading
utilizing high inflow (50% Dependable Year) |
480.35 GWh |
Design Energy
Generation including 10% overloading utilizing high inflow
(90% Dependable Year with 95% machine availability)
|
435.22 GWh |
|
Annual Plant
Load Factor |
51.22 % |
|
|
|
FINANCIAL ASPECTS |
|
Levelized Tariff (35 years) for Design Energy
at 90%
Dependable Year |
Rs 2.02 /kWh |
|
FIRR at
Rs.2.09/kWh tariff
|
9.85 % |
|
FIRR at
Rs.2.25/kWh tariff |
11.23 % |
|
CONSTRUCTION PERIOD |
|
Construction
Period in months (excluding pre-construction works) |
33 months |
|
|
|
|
| |
| |
