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detection of possible problems such as thermal runaway. Appropriate action can then be taken to reduce the load. DTS systems are also

Subsea useful for locating hot spots on the cable. Once identifed, these can be rectifed, so that the cables can be operated at their nominal temperature. Temperature trends identifed from the DTS measurements enable the power distributor to maximize the use of a circuit during periods of peak loading such as mid-ummer.

Figure 2. DTS data is collected and displayed as a 3D function of temperature, distance, and time.

Future considerations

The hardware already installed in this DTS application has the potential for several enhanced functions. One of these is a real-time rating system that would allow the operator to automatically generate cable power/load calculations, based on the real-time cable temperature. Using the same fber optics, it is also possible to install intervention monitoring systems that will inform the operator when a third party is performing an action that may damage the cable. For example, it could detect if a ship has dropped its anchor above the cable. Similar systems have been used to fnd short circuits, and can inform the operator where the fault is to

Figure 3. This DTS example from another installation demonstrates how easily within a few meters. hotspots can be identifed to guide workers to within 2m of any problem. trigger an alarm message if the are from other installations. is a

Gary Parker cable temperature in a particular However, the data demonstrate how technical sales zone exceeds a predetermined hotspots can be easily identifed so manager at Sensa, a temperature limit. The DTS that, if necessary, an investigation Schlumberger com- information will allow the company team can be guided to within 2m pany, focusing on to extend the life of the cable by of the correct location (Figures 2 providing solutions to reducing the power load in the and 3). the power transmis- event of an over-temperature. The DTS system is providing sion industry in Europe and the

Alternatively, with continuous EirGrid with valuable data CIS. His responsibilities include monitoring, utilization of the cable on the health of its East-West developing opportunities in emerg- can be increased with the assurance Interconnector cable. The ing markets. Parker holds a Bach- that it is operating within safe measurements enable the cyclic elors degree in electrical engineer- temperature limits. (daily, monthly, and yearly) ing from the University of Lincoln, Realizing the value of assets such behavior of the cable to be UK, and a Masters degree in elec- as power cables requires using established, providing a basis tronics from the University of Lyon, them at their optimum capacity. from which variations in its usual France. He is a member of the

Real-time temperature monitoring thermal behavior can be analyzed. Institution of Engineering & Tech- enables the prediction and The system can be programed to nology (IET).

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