The Rampur hydroelectric power plant (RHEP) is a 412MW hydropower station situated on the Satluj River in the state of Himachal Pradesh, India.
The project was developed by Satluj Jal Vidyut Nigam, a joint venture of Government of India and the Government of Himachal Pradesh.
The power station is located downstream of the existing 1,500MW Nathpa Jhakri hydroelectric power project (NJHEP), the biggest operating hydroelectric power plant in India. It is designed to utilise the desilted water of NJHEP and can generate approximately 1,770.68GW of electricity a year.
Himachal Pradesh is entitled to receive 30% of the power generated by the Rampur power plant on a bus bar rate basis, in addition to 12% royalty on the power generated. It is further entitled to receive electricity under the Gadgil formula as a member of northern grid state. The balance power is allocated to the northern grid.
Although the project was initially estimated to cost Rs33.97bn (approximately $665m), it was later revised to Rs42.33bn in 2017 due to cost overruns.
Rampur hydroelectric power project details
The Rampur power plant works in tandem with the upstream 1,500MW Nathpa Jhakri project and comprises headrace tunnel, tailrace tunnel, penstocks, powerhouse, power evacuation system, and other components.
RHEP uses the desilted water from NJHEP, which eliminated the need for the construction of a dam or reservoir or a de-silting chamber. Both RHEP and NJHEP plants run in tandem and are operated by a Tandem Operating System (TOS), comprising a simulator for simulating the upstream and downstream hydropower plants.
The discharged water from NJHEP is carried downstream through a 15km concrete-lined underground head-race tunnel to the steel penstocks. The penstocks have a diameter of 5.4m each and deliver water to drive the six turbines installed in the powerhouse.
The powerhouse at Rampur HEP is located at the surface and was constructed on the left bank of the River Satluj near Bael Village.
The power generated at the plant is transferred to the northern grid by looping in looping out of the 400kV Jhakri-Nalagarh double circuit line at Duttnagar.
Rampur power plant details
The Rampur power plant consists of six vertical axis Francis turbine units of 68.67MW each, supplied by BHEL. The turbines have a speed of 214.3 rpm and are operated with a net design head of 119.1m.
The plant includes six generator units with a power capacity of 83.93 MVA each.
Construction of Rampur hydroelectric power plant
The Rampur power plant construction began in 2007 and is estimated to involve the use of approximately 300,000m³ of concrete, 133,000t of cement, and 5,057t of structural steel. Conventional drill and blast method was applied for the tunnel excavation.
The initial design was revised due to poor geological conditions on the site. The works required increased excavation for accommodating ribs and lattice girder. Installation of 32mm diameter rock bolts was undertaken instead of 25mm diameter and longer rock bolts up to 7m in length had to be used.
Other changes included the use of face shotcrete to avoid collapse and draft tube gates for the sudden closure of units and surge shaft gates, increase in the thickness of lining, and an increase in the thickness of penstock liner.
The project was financed through 70% debt and 30% equity. The World Bank provided $400m loan facility for the plant.
The indigenous State Bank of India (SBI) also provided debt for the project.
BHEL was awarded a contract in September 2008 for providing the electro-mechanical equipment package for the Rampur hydroelectric project. The package includes the provision of Francis turbines with matching synchronous generators, digital governors, microprocessor-based controls, monitoring and protection system, switchyard and 400kV GIS, and other associated equipment.
The construction contract worth Rs8.06bn ($182m approximately) was awarded to a joint venture of Gammon India and Patel Engineering in February 2007. The contract included the construction of the headrace tunnel, surge shaft, and the powerhouse.
BEKK Solutions, the Indian contracting arm of the GBFC, was awarded a subcontract by Gammon for conducting ground consolidation and grouting operations at the project site.
BHEL awarded a sub-contract to Fitwell Power Projects for material handling, erection, and commissioning of Francis turbines, generators, and control cables.