Distributed Temperature Sensing (DTS) for long power cables
Power cables have an anticipated life of 40 years, many last much longer.
Knowing their temperature behavior can help you understand their condition and where they are in their lifecycle. Why replace a power cable when all is going well?
Most high voltage HV and EHV cables have optical fibers included for monitoring the cable’s temperature.
fibrisTerre interrogators use Brillouin Frequency Domain Analysis (BOFDA). This technique provides advantages for monitoring longer power cables.
At 50 km, a fibrisTerre system detects temperature changes with a 1 m spatial resolution.More precise measurement provides
This means you can monitor the cable’s temperature and condition continuously, all along its length, and receive alarms when the temperature, anywhere along the cable, strays outside its preset limit.
Direct buried, in ducts, and cables in tunnels – all benefit from continuous temperature monitoring.
Challenges to power cables include:
A fibrisTerre system detects and reports temperature events continuously, allowing the cable to be operated at maximum load, without exceeding its maximum permitted operating temperature.
Offshore windfarms continue to push the boundaries for power cables
Higher voltage cables are required to transport the electricity and improve the economics of installation, with inter-array cables increasing to 66 kV and export cables moving to 275 kV.
Interconnectors enable energy to be moved efficiently between countries and continents, offering enormous value to populations and businesses.
Direct Electrical Heating (DEH) cables and umbilicals are subject to rapid changes in load.Temperature along the cable is monitored to ensure the asset is operating within pre-defined limits. If the heating fails, the system can trigger a pipe or flowline shutdown.
The cost of cable failure is high; repairs are slow and difficult.
Condition monitoring with a fibrisTerre system helps you detect and locate an incipient fault, giving you time to mitigate its effects.
Interconnectors, export, and umbilical cables may suffer strain during installation or rock dumping.
In operation geological faults, scouring, seabed movements, anchor drag, or landslides may strain the cable, even causing it to fail.
The expected lifetime of dynamic floating offshore wind farm cables is difficult to predict.Dedicated fiber optic strain sensing incorporated within the cable
Combining strain and temperature monitoring provides insight into the integrity of dielectric materials. The data may be compared to models or digital twins to inform cable maintenance and life expectancy decisions.
Duct settlement, ground movement, or climate effects may affect a cable.
Including a strain sensing fiber within the power cable structure allows it to be monitored, either permanently or surveyed periodically to measure how the strain is developing.