Andritz Hydro – HPP Upper Tamakoshi, Nepal – Successful pressure test of penstock

In February 2021, the pressure test of the lower horizontal penstock for the Upper Tamakoshi hydropower plant in Nepal was successfully completed to the utmost satisfaction of the customer.

A penstock portion of 377 m length along with six bifurcators and branch pipes was subjected to 115.1 bar for 30 minutes with water volume of 1.4 million cubic meters. The complete test was conducted over a period of 10 hours. It is worthwhile to mention that the entire lower vertical and horizontal penstock was 100% weld repaired on-site and the bifurcators were repaired, modified, and aligned also on-site.

The penstock of Upper Tamakoshi HEP is designed for a water pressure of 905 meters, the diameter is varying from 1.47 meters to 3.6 meters with two vertical and two horizontal shafts. The upper vertical shaft has a depth of 310 meters and the lower vertical shall has a depth of 370 meters.

After the successful supply, installation and dry commissioning of the entire electro-mechanical equipment for the Upper Tamakoshi hydropower plant, ANDRITZ also received the contract to take over the refurbishment and commissioning of the gantry crane, 100% weld replacement of already supplied pipes by another contractor and installation of lower vertical and horizontal penstock.

The work was very challenging considering the quality issues of the preliminary delivered equipment and the difficult site conditions. However, the on-site team from ANDRITZ Hydro did an excellent job to not only execute this additional order in time and with top-tier quality, but also to strengthen the confidence of the client in the work of ANDRITZ.

This order once again underlines ANDRITZ’ strong market position in Nepal as one of the leading suppliers of equipment and services to the HYDRO industry as well as highlighting the company’s expertise in project execution and project management.

Upper Tamakoshi is the largest hydropower plant in Nepal with an underground powerhouse. It has a total capacity of 456 MW to meet the country’s growing power demand.

Technical Details:
Total output: 456 MW
Penstock length: 760 meters.
Penstock diameter: 1.47 to 3.6 meters