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Home / Technical Articles / What to expect from an old GIS, and what are the options for support and life extension

What to Expect From Operating Old GIS

Every new GIS switchgear eventually gets old and obsolete at the end of its lifetime. Problems with GIS, as with every other switchgear type, typically start after the midpoint of the lifecycle. This is the point at which the end user expects to receive support from the GIS manufacturer. The aim of this article is to provide an overview of what an end user can and what cannot expect from a manufacturer regarding the support for an old GIS and what options for GIS life extension he has.

What to expect from an old GIS and what are the options for support and life extension
What to expect from an old GIS and what are the options for support and life extension

Given that the GIS is an integrated system of functional components, a residual life decision cannot be made solely by considering individual parts, such as circuit breakers or disconnectors. The evaluation must encompass the entire GIS installation.

The deterioration of the equipment will be affected by the frequency of operations, component wear, electrical stressors, and temperature effects on sealing materials. Life expectancy can be enhanced through optimal service conditions, proper maintenance, and the prompt replacement of damaged components.

Studies of several GIS installations operational for over 40 years reveal significant life expectancy; nonetheless, identifying the end of life is a multifaceted issue.

This technical article references the “Manufacturer” and “End User” of GIS. However, due to the significant changes in the electrical industry, the original manufacturer and, indeed, the End User may differ from those present at the time of the equipment’s initial installation.

These alterations may lead to the loss of technical information and expertise, hence complicating the evaluation of residual life and potential methods for its extension.

Table of Cntents:

  1. Support for an Old Discontinued GIS
    1. Knowledge, Expertise and Skills
    2. Problems With Spare Parts After 10-15 Years?
      1. Availability of Spare Parts
      2. Spare Parts Holding Policy
      3. Spare Parts for GIS Secondary Equipment
    3. Who Performs Maintenance and Repair?
    4. What are the Options for Extension of the Existing GIS?
    5. Consultancy Services for GIS Residual Life
  2. What are the Options For GIS Life Extension?
    1. The Magic of Enhanced Maintenance
    2. Refurbishment of the GIS
    3. Retrofit of the GIS
    4. …and Finally Replacement of the GIS
  3. Attachment (PDF) 🔗 Download ‘Detailed Design and Analysis of GIS for Electrified Railway System’

1. Support for an Old Discontinued GIS

Normally, the end customers anticipate support for the recently discontinued Gas-Insulated Switchgear (GIS). Manufacturers frequently offer support throughout the equipment’s service life. The subsequent paragraphs provide examples of potentially available services.

The manufacturer’s problem in delivering this assistance lies in balancing the prolonged lifespan of the GIS with the industrial trend of reducing product life cycles.

Given that manufacturers’ product obligations may have evolved over the lifespan of the installed equipment, it is advisable for end users’ asset management policies to include the maintenance of up-to-date contacts for service and spare parts.


1.1 Knowledge, Expertise and Skills

The knowledge and skill of both end user and manufacturer personnel regarding the equipment must be taken into account. Many of end users have reduced their workforce by outsourcing a significant portion of maintenance tasks to contractors or manufacturers, resulting in a loss of essential knowledge.

Manufacturers may have lost proficiency as new equipment ranges are launched, resulting in limited familiarity with earlier equipment kinds. The consolidation of manufacturing into a restricted number of plants, accompanied by the closure of some, has been another contributing factor.

Manufacturers generally retain expertise for maintenance and repair. However, staff may not always be readily accessible to perform these tasks. Most manufacturers possess internal policies mandating the retention of all designs, molds, material specifications, and essential documents, including type test and routine test data, manuals, etc., throughout the equipment’s entire lifespan.

Both consumers and manufacturers usually experience a loss of professionals knowledgeable about older technology owing to retirement. The inherent reliability of GIS has simultaneously extended maintenance intervals and decreased the skill levels required for maintenance activities. Retraining may be necessary prior to conducting repairs on antiquated equipment.

Maintaining knowledge of GIS over one’s career is a significant difficulty for both end users and manufacturers in the future. An inadequate level of expertise may result in the premature obsolescence of the GIS before the technical or operational factors need it.

Figure 1 – Substation engineers preparing GIS extension

Substation engineers preparing GIS extension
Substation engineers preparing GIS extension

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1.2 Problems With Spare Parts After 10-15 Years?

The integrated nature of GIS necessitates that all components be supplied from a single provider, hence elevating the significance of spare parts availability.

The situation gets worse by the decreased need for spare parts, challenges in testing and recertification, particular storage requirements, and typically extended manufacturing lead times.


1.2.1 Availability of Spare Parts

Manufacturers often provide spare parts for a minimum of 10 to 15 years following the end of production of that GIS type, and frequently for an extended duration. Perhaps after this period, it may still be feasible to get spare parts, but at a premium cost and with extended lead times, owing to reduced or perhaps singular production batches and the availability of raw materials.

The financial and time considerations of acquiring spare parts may influence the decision regarding residual life. Replacement components may incorporate modern materials and designs that enhance performance compared to the original fittings, such as EPDM seals and grading capacitors.

Consumable spare parts (e.g., seals, desiccants) are perpetually accessible for maintenance and repair. If a consumable item becomes unavailable, the manufacturer might offer or suggest appropriate substitutes.

Figure 2 – Gas-insulated switchgear spare parts stock

Gas-insulated switchgear spare parts stock
Figure 2 – Gas-insulated switchgear spare parts stock

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1.2.2 Spare Parts Holding Policy

Diverse alternatives are available for spare parts. Some end users acquire extra parts alongside the primary equipment; nevertheless, the storage of these spares frequently poses a challenge, resulting in many becoming unusable when needed. Others establish agreements with the original equipment manufacturers to retain spare parts on their behalf.

Certain end user groups establish agreements to maintain a shared reserve of spare parts, thereby offering reciprocal assistance. Occasionally, these pooled spares are kept at the GIS manufacturer’s facility. This specific method may be suitable at the conclusion of the manufacturing of a certain form of GIS.

This facilitates cost-sharing and enhances the availability of a diverse array of components.

It’s important to note that the optimal technique is contingent upon the end user’s spare parts policy, technical proficiency, manufacturing lead time, equipment volume of a specific type, and geographic location.

Provided the circumstances permit, the deconstruction of an obsolete GIS may create the chance to utilize the components or bays as sources for spare parts or additions, if relevant.

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Edvard Csanyi - Author at EEP-Electrical Engineering Portal

Edvard Csanyi

Hi, I'm an electrical engineer, programmer and founder of EEP - Electrical Engineering Portal. I worked twelve years at Schneider Electric in the position of technical support for low- and medium-voltage projects and the design of busbar trunking systems.

I'm highly specialized in the design of LV/MV switchgear and low-voltage, high-power busbar trunking (<6300A) in substations, commercial buildings and industry facilities. I'm also a professional in AutoCAD programming.

Profile: Edvard Csanyi

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