Summary
The design of external insulation for high‑voltage apparatus and substations primarily aims to prevent corona discharges, define the required air clearances, and ensure adequate creepage distances. Corona discharges are self‑sustaining electrical discharges occurring in air near electrodes subjected to high electric field stress. In external insulation design, the geometry of equipment electrodes, interconnections, and clearances is defined to prevent discharge inception under maximum operating voltage. The inception of electrical discharges depends not only on air‑gap geometry, but also on atmospheric conditions such as air density, humidity, and voltage stress distribution. Compliance with design requirements is verified through type and routine tests performed in accordance with applicable international standards for high‑voltage equipment and stations.
Read more Read lessRecent advancements in ultraviolet (UV) cameras and optical sensors have significantly improved the ability to detect low‑intensity corona and partial discharge emissions in high‑voltage installations. This capability offers promising opportunities for enhanced monitoring and preventive maintenance. However, the interpretation of such measurements presents challenges for users, equipment suppliers, and station owners.
This paper highlights the challenges associated with interpreting corona and partial discharge observations from both site and laboratory measurements. The presented examples illustrate the influence of environmental conditions, equipment aging, and functional design aspects on observed discharge activity.
In conclusion, while advanced monitoring technologies provide valuable support for preventive maintenance of electrical installations and substations, their effective application requires careful interpretation of results, a thorough understanding of equipment and station design, and detailed consideration of aging mechanisms, environmental conditions, and local electric field sources.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | D1_11733_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Sweden |
| Study committees | |
| File size | 869 KB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
AREVALO Liliana - Hitachi Energy; SOLOVYEV Yury - Hitachi Energy; SUNDRAM Kumar - Hitachi Energy
