Retrofit for High Voltage Gas Insulated Switchgear

Published: Fri 18 Jul 2014
A blog entry by Smart Grid Watch

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Replacing the entire switchgear (especially high voltage switchgear) is a complex and time consuming approach, and not something to be done any sooner than absolutely necessary. Fortunately, utilities can extend  the switchgear's lifetime by replacing vital components. This option has long been available for medium voltage switchgear and now it’s also available for high voltage gas insulated switchgear (HV GIS) for the 1st generation of Siemens HV GIS (8D1/8D2) with a production period from 1968-1978.

Especially the SF6 double pressure circuit breaker used at the beginning of the introduction to the market requires very high maintenance. Nevertheless, it is still in service in many power distribution networks all over the world. Distribution network operators now can replace the first generation circuit breakers with newer technology that requires far less maintenance: the self-compressing 8DN8 circuit breaker, which features a spring operating mechanism. The selected circuit breaker applied for this retrofit solution is used in the current 8DN8 GIS and highly integrated switchgear (HIS) devices.

Siemens offers a High Voltage Gas Insulated Switchgear Retrofit Solution. This package features a low-maintenance spring operating mechanism and no switchgear downtime. This solution can help utilities significantly reduce high voltage switchgear maintenance requirements and costs, thus controlling switchgear lifecycle costs.

Additionally it offers these benefits:

  • All equipment is type-tested in accordance with relevant IEC standards
  • Reduced use of SF6 gas
  • No hydraulic oil required
  • Fewer (and smaller) gaskets needed
  • Further availability of expert knowledge

Adapters are the key to this retrofit solution. Two adapters (type-tested to withstand 650 kV-rated lightning impulse voltage) are needed to connect the new circuit breaker to existing switchgear. Combined with a new 8DN8 circuit breaker, these components comprise a new SF6-gas compartment for the switchgear. This is controlled by the circuit breaker’s SF6 gas density monitor.

Technical specifications:

•         Rated impulse withstand voltage: 650 kV

•         Weight of each adapter: approx. 200 kg

•         SF6 filling pressure: 20°C: 0.61 MPa

•         SF6-gas required per adapter: 28 kg

More information: See fact sheets below, and Siemens Modernizations and Extensions Website

Questions: Please comment below or contact Siemens directly.

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