Keeping the grid flowing with advanced subsea cable monitoring
Renewable energies
28 June 2024
9 min
Subsea cable monitoring

Power grids are undergoing a monumental transformation. Driven by the energy transition, vast offshore wind farms are sprouting across the globe, promising a more sustainable future.

Connecting these remote parks to the mainland grid requires a crucial but often overlooked hero: the submarine power cable.

Imagine these cables as the silent arteries of the energy sector, carrying enough electricity to light entire cities. Their importance is undeniable – a single high-voltage cable tripping can put energy security at risk.

These underwater giants, stretching for hundreds of kilometers, face a unique set of challenges. Unlike their above-ground counterparts, they’re largely hidden from view, making proactive maintenance a critical and complex task.

Yet, recently, a declaration announcement emanating from six North Sea countries and NATO has emphasized the significance of infrastructure security and robustness.

This is where cable monitoring comes into play.

subsea cable monitoring

Why subsea cables monitoring matters

Think of it like this: you wouldn’t ignore a persistent knocking sound in your car engine. If a strange rattle might not be a cause for immediate alarm, it’s still a signal to get it checked before it develops into a major breakdown. In the same way, cable monitoring allows us to diagnose potential problems with subsea cables before they morph into a crisis.

A sudden subsea cable failure will disrupt the delicate flow of electricity within a grid and could trigger various event, ranging from minor frequency shift to more serious issues like brownout, where voltage dips and appliances struggle to function properly. In extreme cases, it could even lead to a complete blackout – a situation where entire regions are plunged into darkness, disrupting everything from traffic lights to hospitals.

By constantly monitoring the health of subsea cables, we gain real-time insights into any potential issues. These insights allow grid operators to take preventative actions, such as rerouting power or scheduling maintenance, before a minor problem escalates into a full-blown emergency.

Monitoring of subsea cables: 3 main challenges

Due to the increasing reliance on offshore power sources, grid operators are being faced with changes and challenges. Here’s a closer look at some of the key concerns:

1. The end of a decentralized past

Traditionally, cable health data was scattered across individual local control rooms and equipment, making it nearly impossible to get a holistic view of the system. It was like having ten different doctors analyzing your health, each with their own reports and interpretations.

Thankfully, the tide is turning. We’re witnessing a shift towards centralized platforms that consolidate data from various sources, offering a comprehensive view and enabling faster, more informed decision-making.

2. The data deluge: Making sense of the noise

But the journey to a truly robust monitoring system isn’t without its obstacles. One major hurdle is the sheer volume of data generated by an array of sensors. Imagine being bombarded with continuous data streams from a thousand sensors – how do you identify a subtle change that can lead to a threatening event?

Another hurdle arises from the fragmented nature of the monitoring landscape. Different vendors often use proprietary technologies, making it difficult to integrate data from various monitoring systems. This creates a tangled web of information, hindering efficient analysis. The ideal solution lies in open platforms that seamlessly integrate with diverse monitoring technologies, providing a unified view of cable health.

3. The limitations imposed by longer interconnections

Subsea interconnectors, the power cables linking distant grids across vast stretches of ocean, pose a unique challenge for traditional monitoring techniques.

Take, for instance, the ambitious Great Sea Interconnector project, a planned high-voltage cable stretching a staggering 900 kilometers to connect the power grids of Greece and Cyprus.

At such immense distances, conventional monitoring methods using optical fibers suffer from signal attenuation – essentially, the message gets weaker as it travels, making it harder to detect issues.

To overcome this challenge, the integration of technologies akin to those used in transoceanic cables, such as amplifiers, is essential. Amplifiers can boost the signal strength at regular intervals along the cable, ensuring that monitoring systems maintain accurate and reliable communication.

cable monitoring, optical fiber

5 advanced techniques for subsea cables monitoring

Thankfully, the world of cable engineering can count on plenty of solutions. Here are some of the cutting-edge technologies playing a vital role in safeguarding the health of subsea power cables.

Monitoring and the revolution of artificial intelligence (AI)

Of course, AI is among the most promising revolutions for the monitoring of subsea cables.

Indeed, the sheer volume of data generated by advanced monitoring systems can be overwhelming. This is where AI steps in, helping to:

  • Filter Out Noise and Identify Threats: By analyzing complex data patterns, AI can effectively distinguish between background noise and real threats. This ensures that operators focus their attention on the most critical issues.
  • Predictive Analytics: AI can leverage historical data and real-time sensor readings to assist in identifying potential problems before they even occur. This allows for preventative maintenance and minimizes downtime.

The road ahead: Monitoring powered by constant innovation

Imagine a user-friendly cockpit that displays real-time data, analyzing failure modes, and proposing remediation actions for all your cable assets in single place: this, in essence, is the future of cable monitoring.

Comprehensive cable monitoring solutions are paramount. A centralized approach not only simplifies cable management but also empowers operators to make informed decisions quickly and efficiently.

Nexans, at the forefront of these innovations, has developed a solution that isn’t just an abstraction layer: it is a versatile data platform, with state-of-the-art digital frameworks, intuitive dashboard and harmonized analytics that brings the cable data management to the next level. It integrates information from various sources and presents a clear picture of the network’s health.

Built to scale, it adapts seamlessly to the growth of the grid. Whether through on-premise deployment or cloud-based access, this solution offers flexible options. Prioritizing cybersecurity, the platform utilizes the latest technologies and maintenance processes to safeguard critical data.

Integration of Nexans' platform - architecture schema

The energy transition depends on the silent guardians of the grid – subsea power cables. As we harness the power of offshore wind farms, robust cable monitoring becomes an indispensable tool. By overcoming the challenges of data management, signal interpretation, and technological fragmentation, we can ensure the health and longevity of these critical underwater connections.

Innovative monitoring technologies can help the silent heroes under the sea to continue to play a vital role, ensuring the lights stay on and our cities vibrate with sustainable energy.

Aymeric André


Aymeric André works as New Solutions Manager at Nexans within the Sales & Marketing department of the Generation & Transmission Business Group.

In 2019 he joined Nexans Services and solutions team within the Innovation Service and Growth Department as a Design Lab Manager for asset monitoring to help enhance the company’s digital offers.

He has previously worked at the SuperGrid Institute where he led a research program on high voltage subsea technologies.