Summary
Gas-Insulated Switchgear (GIS) substations, utilizing SF₆ gas insulation, offer compactness, high reliability, and reduced maintenance, making them ideal for space-constrained hydroelectric projects [1]. However, underground hydro projects, particularly in Himalayan terrains, present unique challenges due to extremely limited space, multi-level equipment arrangements, and restricted accessibility. Integrating GIS alongside transformers and interfacing with Pothead yard in confined caverns requires meticulous layout optimization, coordination with civil works, careful cable routing, and consideration of operational, maintenance, and safety requirements.
Read more Read lessThis paper presents practical experience from the design of a 400 kV GIS substation for an underground hydro project in high-altitude Himalayan region of Uttarakhand (India), where available space was significantly below conventional norms. A modular, distributed GIS configuration was used to optimize space utilization when interfacing with generator transformers, while also ensuring dependable connectivity with the generator transformers and
EHV cables. The design incorporated multi-storey arrangements, prefabricated GIS components, and innovative routing solutions to overcome space constraints without compromising maintainability or safety.
A detailed case study illustrates the challenges encountered during layout design, including civil and electrical interfaces, equipment accessibility, and operational considerations, which includes manoeuvring of maintenance kit and equipments, along with the solutions implemented to address them. The lessons learned provide a benchmark for future underground hydro projects, demonstrating how optimized GIS layouts can reduce civil construction costs, enhance system reliability, and enable safe, efficient operation in highly constrained underground environments.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | B3_10514_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | India |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
YADAV* Baidyanath - BHEL, INDIA; SHUKLA Dileep - BHEL, INDIA; KAPIL Vivek - BHEL, INDIA
Keywords
