HelWin beta – Buttel HVDC Line is a 320kV underground line with a length of 130km from HelWin beta, Schleswig-Holstein, Germany, to Buttel, Schleswig-Holstein, Germany.

Construction works on the HelWin beta – Buttel HVDC Line started in 2014 and the project was commissioned in 2015.


The HelWin beta – Buttel HVDC Line, which is an underground line, is being operated by TenneT TSO. The HelWin beta – Buttel HVDC Line is a new line. The line carries direct current (AC) through double circuit cable.

HelWin beta – Buttel HVDC Line project development status

The development of the HelWin beta – Buttel HVDC Line project was approved by Federal Network Agency in 2014 and the project works were completed in 2015.

Contractors involved

Prysmian Cables & Systems and Siemens was appointed by TenneT TSO to supply the cables for executing the 320kV HelWin beta – Buttel HVDC Line.

About TenneT TSO

TenneT TSO GmbH (TenneT TSO) formerly Transpower Stromubertragungs GmbH, a subsidiary of TenneT Holding B.V., is an electricity transmission system company that administrates and maintain national transmission grid. The company provides system services, power transmission, and facilitates a smoothly functioning of liquid and stable electricity market. It offers services such as constructs new lines, replacing old electricity connections and builds stations and connects new power plants to integrate wind, solar and other types of renewable energy. TenneT TSO provides services to governments, interest groups, suppliers and investors.


All publicly-announced T&D Line & Substation projects included in this analysis are drawn from GlobalData’s Power IC. The information regarding the projects is sourced through secondary information sources such as country specific utility players, company news and reports, statistical organisations, regulatory body, government planning reports and their publications and is further validated through primary from various stakeholders such as power utility companies, consultants, energy associations of respective countries, government bodies and professionals from leading players in the power sector.