Air is the most commonly used insulating tool in the transmission grid. However, to fasten conductors in open-air environments, various types of insulators are required. These devices prevent the flow of electrical current between two points, helping to avoid short circuits and ensuring the safety of electrical installations.
It is important to consider that the insulating properties of air depend on factors such as humidity and temperature. Therefore, the necessary distances to ensure adequate insulation are regulated to meet any atmospheric conditions. While air is constantly renewed through movement, insulators are subject to conditions that can impact their effectiveness.
Wind-driven particles accumulate on their surfaces, and factors such as condensation, evaporation, rain, and varying weather conditions over time can compromise their insulating capacity either temporarily (until the insulator is cleaned) or permanently. That said, there are two main types of insulators:
- Traditional (glass and porcelain)
- Polymeric or composite (silicone with a fibreglass core)
How is insulator life expectancy calculated?
Insulator deterioration is a gradual process and can calculated or predicted to an extent. Measures can be taken to preserve them, primarily through surface cleaning. Polymeric insulators require less frequent cleaning, as the hydrophobic properties of silicone allow for improved insulation performance.
Therefore, insulators are properly cared for through cleaning and replacement programmes (mostly switching from glass to silicone), but there is room for optimising their installation, usage, and maintenance. Ground-breaking technologies are being tested in the transmission grid to support such optimisations and are expected to gain importance in the future.
What happens when electrical insulators deteriorate, and how can it be prevented?
Insulator degradation and deterioration can reduce their insulating capacity and, in the case of composite insulators, degrade the fibreglass core to the point of potential brittle fracture. Although composite insulators are increasingly popular due to their expected durability and performance, their future relies on new methods to verify their long-term operation. Indeed, current quality checks on the insulator core do not seem enough to prevent potential future brittle fractures.
Contamination build-up is the primary cause of insulator degradation. To monitor these conditions, reference maps are created using probes across different regions, while existing grids are analysed using various technologies to understand insulation performance. Improving these technologies and conducting comparative tests is necessary to optimise both costs and performance.
New technologies for preventing electrical insulator deterioration
Some tests with high-frequency visible-light optical systems have been conducted, although further research and cost-reducing adaptations using conventional cameras are needed. Ultraviolet light cameras, though costly, have low-cost sensor alternatives that have already proven to be successful in detecting fires near transmission lines. Direct measurements of currents at various frequencies through different setups are another option, all requiring advanced data analysis.
Such analysis involves centralised electrical and meteorological data collection, particularly as sub-stations—compared to lines—are more easily equipped with power and communication, whereas isolated supports rely on autonomous systems powered by low-energy devices and IoT communications.
This approach enables us to determine the exact condition of an insulator at any given time, optimising both the design of new insulators in the area and the cleaning needs of insulators currently in service. Furthermore, the vast amount of data collected from various locations, combined with the complex dependency on local weather conditions over time, makes this an ideal case for applying AI.
In conclusion, air insulation and insulators—some of the most widespread and traditional technologies in electrical systems—stand to benefit significantly from these new technologies. Given the extensive number of insulators throughout the grid, any advancement in this area will have a substantial impact.