Power Department of Sikkim OR Sikkim Power Department
Rangit-IV HEP
Description

The state of Sikkim located in Eastern Himalaya under the benign shadow of guardian deity Kanchenjanga is bordered on the West by Nepal, on the East by Bhutan and on the South by Darjeeling District of West Bengal and lies between 27° to 28° North latitudes and 88° and 89° East longitudes. The state is surrounded by important mountain ranges. With a total geographical area of 7100 sq.km. Sikkim has two main river systems - Teesta and Rangit. The river Teesta originates in the glaciers of Sikkim and Rangit river originates in Talung glacier in West Sikkim and joins the Teesta near Melli near the Sikkim and West Bengal border.

Rangit Stage - IV H.E. Project was identified as a part of Master Plan evolved in 1974 for the development of hydro power potential of Teesta and Rangit rivers. The Govt. of Sikkim as a part of national drive for the development of Hydro Potential of the country has awarded Rangit Stage - IV H.E. Project on river Rangit to Jal Power Corporation Ltd. (JPCL) on Build Own Operate Basis (BOOT) in December 2005.

The Rangit - IV H.E. Project is a run of the river scheme located in West/South Districts of Sikkim utilizing the dependable flows available in river Rangit for generation of Power by installation of three generating units of 40 MW each. The project envisages construction of concrete Dam near Reshi village, a 6488 m long Head Race Tunnel and a Surface Power House at the confluence of Rothak Nala and river Rangit for utilizing a head of 103.67 m. The tail waters discharged from the turbines will flow through a 42 m long tail race channel to rejoin the river near Rothak Nala. The project is 135 km from the nearest airport Bagdogra near Siliguri in West Bengal and 100 km from the nearest Rail head New Jalpaiguri connected by all weather Highway from Siliguri.

MAJOR COMPONENTS OF THE PROJECT

Dam and Intake Structure

The Dam is 44 m high (above deepest foundation level) concrete gravity type and is located about 1 km upstream of Reshi village. The Dam is 135.30 m long and 8 m wide at the top. Gross storage capacity of the reservoir is 1.81 MCum and the Lve storage capacity is 1.22 MCum. There are 4 sluice spillways of 14m x 10.5m size provided with radial gates and 3 non overflow blocks.

Head Race Tunnel

The head race Tunnel is 6.4 m dia Modified Horse Shoe shaped and 6448 m long designed for a discharge of 128 cumecs.

Surgeshaft

A restricted orifice type surgeshaft of 18 m dia and 59 m height is provided to absorb transient pressure due to load variations; Dia of orifice is 2 m

Pressure shaft

A steel lined pressure shaft of 5.5 m dia having vertical/horizontal run of 247 m is provided to carry a discharge of 128 cumecs.

Power House

The power house is surface type of 20.2 m (W) x 75.3 (L) on the right bank of Rangit river at the confluence of Rothak Nala and river Rangit.

Location of the Project

  • District : West and South Sikkim
  • River : Rangit
  • Name of the river basin : The Brahmaputra
  • Nearest Airport : Bagdogra - 135 km
  • Nearest Railhead : New Jalpaiguri (BG) - 100 km
  • Capacity : 3x40 MW

Coordinates of major structures

Dam : N=27° 14'01", E= 88° 18'05"

Surgeshaft : N=27° 10'22", E= 88° 17'50"

Power House : N=27° 10'15", E= 88° 17'52"

Financial Closure

The Company has achieved the Financial Closure on March 2010 and signed Common Loan Agreement with the Lenders on 25.03.2010. The debt equity ratio is 75:25.

Evacuation Transmission Works Status

Power is to be evacuated by 220 KV D/C line from outdoor switchyard to pooling station of PGCIL at New Melli (Tokal)

The Land acquisition of transmission system for power evacuation from Power house of Rangit-IV, HEP, Rothak to PGCIL Pooling station at New Melli (Tokal) in South Sikkim is under process and "In principle" clearance (Stage-I, Forest Clearance) has been accorded vide memo No. 3-SK B 062/20112-SHI/2885-86 dated 4th December 2012 for diversion of Forest land.

The work for erection of 220K D/C transmission line has been awarded to M/S Ashish Intratech (P) Ltd., Siliguri and the work shall be started after the payment of land compensation to the land owners.

Status of EPC Contract

(As on 31st August 2013)

Package wise contracts awarded for Rangit IV 120 (3 X 40) MW HEP, Sikkim

Project ComponentContractor NameContract Award DateOriginal Contract Value (in INR Crores)
Dam, Intake works & Desilting ChambersCoastal Projects Pvt. Ltd.01.02.2008125.30
Head Race TunnelCoastal Projects Pvt. Ltd.22.11.2007127.90
Surge Shaft, Pressure Shaft, Power House, Tail Race Channel & Switch YardCoastal Projects Pvt. Ltd.06.12.20077.93
Road Diversion TunnelCoastal Projects Pvt. Ltd.06.12.20077.93
E&M Package I-Turbine & GeneratorAndritz Hydro Pvt. Ltd.28.08.2009111.10 + 7.19 = 118.29
E&M Package II-Balance of PlantSiemens Ltd.14.04.201153.80
Hydro Mechanical EcquipmentTexmaco Rail & Engineering Ltd.12.04.201236.70
Power House StabilisationBhumi Geo Engineering Ltd.LOA dtd. 16.01.201030.00
220 Kv Transmission LineAshish Infratech Pvt. Ltd.16.11.20125.42