Gas-insulated DC Switchgear (DC GIS)

Maximum performance at minimum space

Space limitations are an issue with numerous new applications for HVDC transmission. That’s why Siemens Energy has broken new ground in insulation technology to make one of the most space-saving technologies in HV power transmission available for HVDC systems: gas-insulated switchgear (GIS). Siemens Energy DC GIS are based on Siemens Energy’s proven 8DQ1 switchgear technology. The encapsulated, compact, and modular gas-insulated switchgear for DC voltages of up to ±550 kV and currents of up to 5 kA reduce space requirements for HVDC switchyards considerably, boast outstanding climatic resistance. Furthermore, a gas-insulated substation can even be installed underground or commissioned in prefabricated container modules for further space and time savings as well as minimum visual impact.

DC GIS in 132 seconds!

Why Siemens Energy DC GIS?

DC GIS is your answer to any size, climate, and time challenge

Modular Siemens Energy DC GIS help reduce the space requirements for HVDC systems, ensure safe and reliable operation even in demanding onshore and offshore applications, and enable quick project implementation.

Enormous space-savings in offshore applications

The use of Siemens Energy DC GIS reduces the size of an offshore HVDC converter platform by up to 10 percent, because space requirements for the switchgear itself are reduced by up to 95 %: While comparable air-insulated switchgear in standard configuration would require 4,000 cubic meters, Siemens Energy DC GIS require only 200 cubic meters.


A gas-insulated substation doesn’t require a dedicated room. It can simply be added to another technology room on the platform, such as the converter or reactor room. This helps bring down costs.


Siemens Energy DC GIS are suitable for today’s most demanding offshore applications. Type-tested according to applicable IEC standards and CIGRÉ recommendations, gas-insulated switchgears for DC are available for rated voltages of up to ±550 kV.

Less space consumption and visual impact onshore

Thanks to their outstandingly compact dimensions, Siemens Energy DC GIS make it much easier to build a switchyard exactly where it is required when space is limited. At the same time, they help curtail costs when land prices are at a premium. 

Siemens Energy GIS operate safely and reliably even under severe climatic conditions, which means that a gas-insulated substation doesn’t require an extra housing in most cases. The comprehensive range of standardized modules available helps implement even complex arrangements and switchyard layouts without much interface engineering, while commissioning of the GIS switchgear is fast and cost-efficient.

Small footprint and reliable operation for transition stations

Siemens Energy DC GIS reduce space requirements for the switchyard of transition stations to a minimum: The modular, encapsulated, and compact Siemens Energy DC GIS for rated voltages of up to ±550 kV require remarkably less space than technically equivalent air-insulated switchgear – this way bringing down land costs and reducing the visual impact of the switchyard.


In most cases, Siemens Energy DC GIS can be installed in open air without a housing: They operate safely and reliably even under severe climatic conditions. This speeds up commissioning and helps keep costs at bay. 


Thanks to the comprehensive range of standardized modules, even complex arrangements and switchyard layouts can be implemented with very little interface.

Transition stations with hidden switchgear

Siemens Energy DC GIS can be installed underground. This helps keep the visual impact of a transition station to an absolute minimum and reliably prevents unauthorized access. 


Numerous standardized modules are available to enable the flexible implementation even of complex arrangements with next to no interface engineering for the connection of other equipment, such as control and protection devices. 


Siemens Energy DC GIS are type-tested according to applicable IEC standards and CIGRE recommendations and are available for rated voltages of up to ±550 kV. This makes them suited for many new HVDC applications, such as multi-terminal or DC grid systems.

Containerized solutions for extra-fast commissioning

Siemens Energy DC GIS for rated voltages of up to ±550 kV can be delivered prefabricated and pretested in modular containers – a cost-effective solution whenever technical requirements such as extreme environmental conditions require DC GIS to be placed in a housing and when time is at a premium.


The entire substation arrangement is tested at the manufacturer’s and the container builder’s premises for the quickest possible commissioning and smooth, cost-effective interaction with civil works. 


DC GIS layouts that are repeatedly needed, as is the case with transition stations within an HVDC scheme, for example, can be planned and supplied as a cost-effective, standardized series.

From cable to GIL with the least possible effort

Gas-insulated lines (GIL) can be used in HVDC transmission systems. In certain cases, for example, when restrictions due to natural barriers or existing infrastructure must be crossed with challenging routing and minimal use of space.

In such cases, a preassembled and pretested, containerized transition solution based on Siemens Energy DC GIS for rated voltages of up to ±550 kV is the most space-saving, quick, and cost-efficient solution. It also helps reduce space requirements, engineering effort, and visual impact.


Trendsetting technology put into practice

Siemens Energy DC GIS is a fairly new technology, but thanks to its great advantages it has already been included in the design of future HVDC projects that are being planned at the moment.

Learn more about DC GIS

Download our DC GIS brochure to gain an overview of all technical details and possible applications. In addition the infographic provides all Siemens Energy DC GIS references at a glance.

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