How Safegrid helped Griug detect a hidden insulator fault and avoid disruption
Challenge
In November 2025, Griug experienced repeated high-impedance earth faults (EFs) on a line section using covered conductors, a common solution to prevent network faults caused by vegetation.
Covered conductors are also used in wildfire-prone areas due to their improved safety against vegetation contact.
However, covered conductors also introduce a known challenge. Especially high-impedance faults caused by vegetation or insulation defects can be difficult to detect and even harder to locate using conventional methods.
The affected feeder supplied critical customers, making reliability essential. Despite multiple fault indications, the root cause remained unclear and showed no obvious visible damage.
Solution
Using Safegrid’s Smart Fault Prediction functionality, Griug identified a partial discharge (PD) hotspot along the line.
After several detected events, the team conducted a field inspection using an acoustic camera. As a result:
- The fault was located precisely at the predicted hotspot
- A polymer insulator on the covered conductor was identified as the source
- The defect showed only minor visual markings, making it difficult to detect without guided inspection
This case highlights how even modern covered conductor systems can develop hidden insulation issues and how these can manifest as high-impedance faults similar to vegetation-related disturbances.
Results
With accurate insights from Safegrid:
- The faulty insulator was identified before failure
- The affected section was switched to another feeder, ensuring continuity of supply
- A potential outage affecting critical customers was avoided
Another valuable case where we were able to prevent an outage with help of Safegrid’s Smart Fault Prediction functionality.
Espen Sørlie, Operations Manager from Griug
Beyond fault detection, this case demonstrates the broader value of Smart Fault Prediction in vegetation management scenarios, where high-impedance faults on covered conductors are notoriously difficult to detect and locate.
By combining data-driven analytics and precise fault localization, Safegrid enables utilities like Griug to transition from reactive to proactive grid monitoring.
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