Telharkund Pumped Storage Scheme (4 x 100 MW)

 

Introduction

 

To cater the power requirement of state, Bihar State Hydroelectric Power Corporation Ltd., (BHPC) is trying to exploit the available hydro potential in the state. In the process of identifying the potential sites for hydro power generation, reconnaissance survey was got conducted by BHPC through NHPC to set up large hydel projects in the district of Kaimur and Munger in Bihar. Reconnaissance survey report was submitted by NHPC to BHPC in May 2002. NHPC in it report identified some hydel projects for possible development. It was also found that from geological and topographical considerations, it was possible to develop Pumped Storage scheme at some locations subject to technical feasibility and economical viability.

 

         

Project Purpose

 

Hathiadah-Durgawati fall site is located on the left fork of Sura river in the  Kaimur district of Bihar. The site is located about 50 km from Bhabua road which is the nearest rail head. Sura river is a sub tributary of Durgawati river which is a tributary o Karamnasa river joining Ganga rive Chausa (U.P.). The site is suitable for a Pumped Storage scheme. The power required for pumping the water from lower reservoir to upper reservoir shall be taken from the grid during off-peak hours when it is available at cheaper rates.  This will act as value addition to nearby thermal power plant and improve the grid stability. Pumped Storage Schemes consume energy during off-peak hours thereby improving plant load factor of thermal plants. These can act as spinning reserve and help in improvement of load factor of the system. Pumped Storage Schemes can provide the required peaking support especially during lean season. It also helps in smoothening the frequency curve. Pumped Storage Schemes are independent of vagaries of monsoon. During peak period the Telharkund Pumped Storage Scheme shall be able to provide the required high value power to the State of Bihar.

 

SALIENT FEATURES

 

 

1.0

Location

 

 

Country

India

 

State

Bihar

 

District

Kaimur

 

Nala/River

Sura river (left fork)

 

Project area 

 

Longitude

N 240 51’ 21”

N 240 49’ 44”

 

Latitude

E 830 31’ 18”

E 830 32’ 12”

 

Access to the Project

Bhabua Town  35 (Km)

 

Airport

Patna, Varanasi

 

Nearest Railhead

Bhabua Road (50 km)

 

Port

Kolkata

2.0

Scheme

 

 

Type

Pumped Storage

 

Installed capacity

400 MW

3.0

Hydrology

 

 

Catchment area

61.61 Sq. km.

 

Maximum annual rainfall in water watershed

1300 mm

 

Minimum annual rainfall in watershed

540.0 mm

 

Max Intensity (one day)

131.00 mm / day (at Bhagwanpur) (5.9.1995)

 

Maximum observed flow

21.803 Cumec

(at Telharkund fall) (1.9.1996)

 

Minimum observed flow

0.019 Cumec (At Telharkund fall)

 

Maximum design flood 250 Cumec
 

Annual average sediment load

0.07 Ha M / sq km /year (at Kadhwan)

 

Annual Average evaporation

145 cm (Average of Kadhwan, Purulia and Koel karo)

4.0

Civil Structure

 

4.1

Upper Dam

 

 

Type

Roller compacted with central spillway

 

River bed level

EL 255 M

 

FRL

EL 315 M

 

Top level of Dam

EL 320 M

 

Maximum height

65 m

 

Top width of Dam

8 m

 

Length of the Dam at top

500 m

 

Spillway 

 

Type

Trajectory Bucket

 

Length

14 m

 

No. of  bays

2

 

Size of bays

3m x 4m

 

Crest Level

El. 265 M.

 

Design Flood

250 Cumec

 

Type of gate

Radial

 

Care of River  

 

Type

Stage Diversion

 

Design discharge

100 cumec

 

Reservoir 

 

MDDL

EL 295 M

 

FRL

EL 315 M

 

Gross capacity

11.69 Mcum.

 

Live storage

9.45 Mcum.

 

Reservoir surface area at FRL

86 ha.

4.2

Lower Dam

 

 

Type

Rock filled with central clay core

 

River bed level

EL 140 M

 

FRL

EL 190 M

 

MDDL

EL 170 M

 

Top level of Dam

EL 195 M

 

Maximum height from bed level

55 m

 

Top width of Dam

8 m

 

Length of the Dam at the top

310 m

 

Diversion tunnel 

 

Length of diversion tunnel

550 m

 

Diameter

5 m horse shoe

 

Invert level

EL 140 M

 

Spillway 

 

Type

Tunnel

 

Length

70 m

 

Invert level

EL 145 M

 

Diameter of tunnel

5 m

 

Design flood

250 Cumec

 

Reservoir 

 

MDDL

EL 170 M

 

FRL

EL 190 M

 

Gross Capacity

15.73 Mcum.

 

Live Storage

9.36 Mcum.

 

Reservoir surface area

50 ha.

4.3

Intake

 

 

Type

Dam body

 

Discharge (With 10% overload)

476 Cumec

 

Gate

Vertical Lift with stop logs

4.4

Pressure Shaft and Penstock

 

 

Type

Partly Steel and concrete lined

 

Number

2

 

Diameter

7 m

 

Length

120 m

 

Penstock 

 

Upper Horizontal

48 m

 

Lower Horizontal

80 m

4.5

Power House Complex

 

 

Type

Under Ground

 

Size of Power House Cavern

125x40x20 m

 

Service bay level

EL 170 M

 

Type of Turbine

Reversible Francis pump turbine

 

No. of Turbines

4

 

Design Head

112.50 m

 

Design Discharge

432 Cumecs

4.6

Transformer Cavern cum gate shaft

 

 

Type

Under Ground

 

Size

110X15X23

Service bay level

EL 192 M

4.7

Tailrace Tunnel

 
  Type D-Shaped
  No. of Tunnels 4
  Diameter 7m
  Tunnel Length (Longest) 115 m

4.8

Switchyard

 

 

Type

Surface

 

Dimension

220 x 120 m

 

Elevation

EL 300 M

5.0

Estimated Cost

 

 

Total Project Cost

(Excluding transmission line)

Rs. 1541.99 Crores at Jan Price level

 

Debt: Equity Ratio

70:30

 

Levellised Tariff

Rs. 4.21 per kWH

5.2 Annual Energy Generation, Off Peak Energy for pumping and tariff  

(a)

6 hours peaking and 8.6 hours pumping
i) Energy generation 873.60 MU
ii) Pumping energy 1260.48 MU
iii) Sale rate at bus bar Rs. 5.33 without free power
iv) Sale rate at bus bar Rs. 6.06 with 12% free power

(b)

4.5 hours of peaking and 6 hours of pumping
i) Energy generation 655.20 MU
ii) Pumping energy 946.40 MU
iii) Sale rate at bus bar Rs. 6.44 without free power
iv) Sale rate at bus bar Rs. 7.32 with 12% free power

(c)

4 hours of peaking and 5.5 hours of pumping
i) Energy generation

582.40 MU

ii) Pumping energy 840.32 MU
iii) Sale rate at bus bar Rs. 7.09 without free power
iv) Sale rate at bus bar Rs. 8.06 with 12% free power