The 525kV DC cables will be used for major connections including SuedLink

Germany’s transmission system operators are using 525kV direct current (DC) cables as part of grid upgrades to facilitate increasing levels of energy, mainly from renewable sources.

The cables will be used for the SuedLink, SuedOstLink and A-Nord connections and will be the first time such connections are used. They supersede plastic-insulated 320kV high voltage cables, used to connect offshore wind farms to the onshore power grid, for example.

The grid operators 50Hertz, Amprion, TenneT and TransnetBW will together debut the 525kV DC cables, which are able to transmit more power.

One advantage of going to higher voltage DC wires is that more electricity can be transported in a given cable corridor with the same number of cables.

Alternatively fewer cables are needed to transmit the same amount of power compared with using 320kV wires.

DC cables are also narrower in profile, further helping reduce civil engineering work during the construction phase and minimising impact on the environment, said the grid operators.

The decision to use the new cables, by 50Hertz, Amprion, TenneT and TransnetBW, occurred following an extensive test phase in which the technical suitability of the 525kV cables underwent investigation, which included testing under maximum loads in test laboratories in Mannheim and Sweden.