Subsea Pinpointing

Context

Pinpointing cable faults faster with Distributed Acoustic Sensing (DAS) technology

As Elia Group expands its offshore grid in the North Sea and the Baltic Sea, submarine power cables are becoming increasingly critical, as they enable the transmission of large volumes of renewable energy. Subsea power cables also interconnect countries, enabling energy trading at large scale. Guaranteeing asset availability is a key priority for us. That’s why we are developing a new, faster way to locate cable faults using Distributed Acoustic Sensing (DAS).

Why it matters

Our DAS-based method allows us to:

• locate faults in subsea cables with an accuracy of less than 10 meters
• speed up repairs and reduce offshore interventions
• increase the availability of renewable energy
• make offshore operations safer and more efficient
• prepare for a future with instant, vessel-free pinpointing

Approach

How it works

Optical fibres inside our cables act as thousands of tiny acoustic sensors. When a fault occurs, the DAS equipment picks up its unique signature and estimates its location. A short offshore check (pinpointing) with a low‑frequency sonar then validates the exact location with high accuracy.

Results

Proven in real offshore conditions

Working with partners, we tested the method across different seabeds and water depths. The DAS–sonar combination consistently identified fault locations with a precision of about ±10 metres. The new method is reliable, simple to deploy and suitable for long-distance export cables.