Assembly of GIS Substations: The critical link to ensure performance, reliability and longevity

However, the successful implementation of GIS technology relies not only on component quality or manufacturer reputation, but critically on the precision, cleanliness, and rigor applied during the on-site assembly process. This technical paper underscores the strategic importance of proper GIS assembly as a key determinant of long-term performance, reliability, and operational safety. Assembly is not merely a construction activity; it is a crucial phase in the lifecycle of a substation, where risks such as partial discharges, gas leaks, internal contamination, misalignment, or premature aging can originate if protocols are not meticulously followed.

The paper offers an integrated theoretical and practical perspective. It incorporates international standards and CIGRE technical recommendations to build a structured framework for quality assurance. Field experience from multiple GIS projects is also shared, including lessons learned from close collaboration with manufacturers during critical assembly stages. Key topics include environmental control, cleanliness management, proper handling and alignment of modules, torque application on flanges and internal connections, vacuum creation, gas handling, and the importance of continuous technical supervision. Special emphasis is placed on verifying internal environmental conditions such as humidity and particle contamination, which are critical to the long-term dielectric integrity of GIS equipment.

The paper also outlines key considerations for control and verification during project execution.

These include the availability of certified tools, qualified personnel, compliance with FAT and

SAT requirements, and strict adherence to manufacturer-specific assembly procedures. Realworld case studies demonstrate how deviations from best practices have resulted in equipment failures or performance degradation, whereas disciplined assembly practices have led to robust and reliable installations, even under demanding conditions.

Through real cases and normative references, it will be demonstrated that successful assembly is not just a project phase, but a structural component of the facility's reliability design.

By highlighting the direct correlation between assembly quality and operational outcomes, this paper aims to raise awareness among engineers, contractors, and utility stakeholders of the strategic role that assembly plays in the reliability and longevity of GIS substations. It provides actionable insights and field-proven recommendations that, when applied rigorously, can significantly reduce project risks and ensure that GIS installations perform as expected over their entire service life.

Finally, this article will provide the reader with a practical guide to verify that, if implemented rigorously, it will maintain the expected levels of performance and reliability for this type of technology in hostile environments.