Siemens eyes switchgear space-cut

Siemens has unveiled a new compact gas-insulated switchgear concept for high voltage direct current (HVDC) applications that could trim offshore substation size by some 10% and change the industrial approach to long-distance electricity transmission.

The German industrial giant expects the new 320kV DC CS (direct current compact switchgear), which uses up to 95% less space compared to previous air-insulated units, to underpin a "new portfolio" of low-loss HVDC transmission technologies.

“With the 320kV DC CS switchgear’s market readiness, we have laid a cornerstone for the development of a completely new portfolio for efficient power transmission," says Denis Imamovic, Siemens' head of development for gas-insulated direct current transmission systems.

"Space-saving direct-current transmission solutions will continue to grow in significance in the future. We believe that the DC CS switchgear will establish itself as the standard for offshore converter platforms and thereby play a major role in decreasing costs for HVDC transmission grid connections.”

HVDC transmission technology is central to development plans to flow wind power generated in the North Sea to load-centres around Europe. Currently, 155kV alternating current (AC) from wind power is stepped up on a converter platform into 320kV DC and then transmitted to land via submarine cables.

On existing offshore converter platform designs, air-insulated DC switchgear requiring about 4,000 cubic metres of space is used.

A DC CS system with the same capacity would need only 200 cubic metres, a 95% smaller footprint.

As well as saving space - and so cost - the newly developed switchgear has other advantages, including an encapsulated, module-based design that is less expensive to ship offshore and "flexible and simple" to set up, as well as being suited to hostile marine environments.

Gas-insulated, three-phase current switchgear has been part of Siemens’ portfolio for decades, but has not be specced-up for HVDC applications.