The Kassø-Tjele high-voltage transmission line is a 400 kV high-voltage transmission line in Denmark from Transformer Station Kassø by Kassø west of Aabenraa to HVDC converter station Tjele by Foulum east of Viborg.

[3] The main purpose of the expansion of the transmission line was to be able to exchange surplus production of electricity with other countries, i.a.

In addition, there would be a risk of fatigue fractures, as the shaft and traverses of the stealth mast were gathered in a single node that would be heavily loaded, and the rigid construction of the mast would not dampen mechanical oscillations sufficiently.

[4] In three places with special natural and landscape conditions, the transmission line is routed through earth cables.

[5] When choosing the mast type and cable suspension, emphasis was placed on minimizing the magnetic field around the transmission line.

[4] In total, the new installation was budgeted to cost DKK 2.5 billion in 2010 prices if the entire connection was made with the overhead line, and DKK 2.9 billion if underground cables were used at 4 environmental focus areas (Gamst Lake Meadows, Billund, Bølling Lake and Nørreå Valley).

They ended up using underground cable in 3 of the 4 areas, at Billund they instead moved the route further west of the city.

The gain is due to minimization of internal bottlenecks and grid losses, and better utilization of wind energy.