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HVDC Disconnectors

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HVDC Disconnectors

Disconnectors (DSC) for HVDC applications are designed to specific constraints and requirements typical for DC applications, that are quite different compared to AC applications. They are requested to withstand DC voltage open gap and to ground to ensure safety for the people in the substation and to permit proper and safe layout configuration. In some cases, like for filter applications, they are requested to break a sum of harmonic currents at a certain voltage (amply smaller than the rated voltage of the disconnector) due to the ripple created by harmonics on the reactances.

All these DC disconnectors take benefit of huge experience and installed base of AC disconnector technology delivered worldwide in regards to design technology and quality e.g. supplier qualification, assembly processes or ISO conformity.

Key Features
  • Self protected design of contacts (L-type contact) preventing pollution deposit and hot spots
  • HVDC design of post insulators
    • High value of minimum creepage distance enforcing height
    • Dedicated shed profiles
  • Specific layout design (also 2 or 3 post insulators for each contact side)
  • High seismic performances
  • Special design of anti-corona rings
Overview
GE Advantage
Knee-Type DSC
Center Break DSC
Vertical DSC
Valve Hall Earthing

Today’s Challenging Environment

Globally the utility environment is becoming more complex and utilities are having to manage new challenges such as:

  • Increasing demand for electricity
  • Connection of remote generation
  • Growth of distant offshore wind
  • Integration of variable renewable generation
  • Need for security of supply
  • Reduce carbon footprint
  • Land costs becoming more expensive
  • New right-of-way access permits increasing difficult to obtain

The only choice for many utilities is to restructure their grid systems to manage these challenges. Utilities are looking for cost effective solutions to transfer power and to improve the quality, stability and reliability of the grid which will anticipate their needs for the next 20 to 50 years.

GE's Solution

High Voltage Direct Current (HVDC) solutions are ideal for supporting existing AC transmission systems or for building new power highways. HVDC is a system which interconnects two AC networks, converting AC voltage to DC voltage, and DC voltage to AC voltage utilizing power electronics technology. HVDC systems enable transfer of power, interconnection of grids, integration of renewables and maximize grid performance.

back to back hvdc interconnectionBack to back HVDC Interconnection

The GE Advantage

GE’s HVDC Disconnectors are developed based on the highest standards for performance, ratings, user convenience and reliability.

Every model is designed utilizing 3D design tools and analysis software to achieve the highest performance. Switches and Disconnectors are thoroughly type tested and subject to routine tests to meet or exceed the latest standards and requirements. Dependent on customer requirements, GE is able to design and supply highly customized products.

Based on years of global experience, deep domain expertise, manufacturing excellence and several deployments across multiple applications and industries, GE has dedicated projects teams working in partnership with our customers to ensure successful equipment implementations. GE provides customers with the following competitive advantages.

Robust Design Leveraging Cutting Edge Technology Provides High Performance and Lower Total Cost of Ownership

  • HVDC disconnectors use the latest technology of contacts in order to ensure maximum protection against pollution and ice, ensuring limited overhead clearance and a very short phase to phase distances, without middle electrode
  • All switchgear is designed to operate within extreme environmental conditions with available options for high elevation, very low and high temperatures (-60 °C to +60 °C), seismic zones, polluted areas, and corrosive atmospheres.

Manufacturing Excellence to Ensure Highest Quality Standards

  • Global manufacturing sites certified according to ISO 9001 and ISO 14001 standards
  • Products are manufactured utilizing GE’s Advanced Production System ensuring the highest level of quality
  • Customized designes available to meet customer application requirements

Extensive Research, Testing and Proven Field Experience Resulting in Enhanced Reliability

  • R&D Competence Centers and associated testing labaratories assure extensive research and testing for DC applications
  • Specific HVDC tests are carried out in laboratories to ensure best performance over life time of assets
  • 400,000+ units of circuit breakers and disconnectors for AC and DC installed worldwide and in service in more than 100 countries

Optional Features for Enhanced System Compatibility, Digital Integration and In-House Expertise

  • Complete monitoring system available for asset management and digital substation integration
  • Full life-cycle support for products, spare parts management and technical training by GE Subject Matter Experts
  • Local Product Sales Specialists provide strong product and technical support
HVDC Substion Bina IndiaHVDC Substion Bina India

Knee Type Disconnector up to 800 kV

Knee Type Disconnector

GE’s knee type disconnector SPO/SPOL has been designed with one rotating and two fixed insulators. Thanks to its folding arm design (knee), it requires limited overhead clearance and a very short phase-to-phase distance. The outstanding gap factor allows a relatively short air gap and a lighter arm. No electrodes are needed in the middle.

The center of gravity is quite low, with great advantages for balancing, seismic withstand and operating torque. The low operating torque permits sure operation using a motor drive mechanism as well as easy manual operation and it does not stress the rotating insulator. The design is contact rebound free resulting in very smooth movement and a relatively fast operation (about 10÷15 s for a 550 kV disconnector).

L-Contact

The main contact can be of the L- type, the solution patented by GE helping to ensure highest protection against air pollution and ice. The L-Contact is also maintenance free and therefore represents the best technical choice for DC applications.

Center Break Disconnector up to 245 kV

Center Break Disconnector

The center break disconnector type S2DA is the most commonly used and economical disconnector, but requires an increased phaseto-phase distance. In the center break design the two arms rotate and the disconnector opens in the center.

Vertical Break Disconnector up to 800 kV

Vertical Break Disconnector

The vertical break disconnector has one rotating and two fixed insulators. The double movement of the blade ensures excellent performance in terms of ice breaking and short-circuit withstand. The vertical break requires a minimal phase-to-phase distance and the main contact can be of the L-type.

L-Contact

The main contact can be of the L- type, the solution patented by GE helping to ensure highest protection against air pollution and ice. The L-Contact is also maintenance free and therefore represents the best technical choice for DC applications.

Valve Hall Earthing Switch up to 800 kV

Valve Hall Earthing Switch up to 800 kV

The valve hall is an important component of the HVDC system. The grounding of a valve hall’s elements is ensured by highly customized earthing switches.

Two different earthing switch designs have been developed by GE:

  • Wall mounted “grasshopper”
  • Floor mounted “semi-pantograph"