Lithuanian Power System Temperature Measurement Optical Cable Technology

Lithuania employs fiber optic-based Distributed Temperature Sensing (DTS) systems to monitor power cables in real time, enhancing reliability and safety of its electrical network.Overview of DTS in Lithuanian Power CablesLithuania's power system, particularly the NordBalt subsea cable connecting Sweden and Lithuania, uses fiber optic sensing technology to monitor cable temperature along its 400 km submarine route and onshore sections. The system employs single-mode optical fibers integrated into the power cables or external telecommunication fibers for buried onshore cables, enabling continuous temperature monitoring along the entire cable length .How Optical Fiber Temperature Measurement WorksThe DTS system uses optical fibers as distributed sensors. When an electric current flows through a power cable, it generates heat due to electron collisions in the conductor material. Excessive temperature can cause energy losses, cable damage, or even fire . The optical fibers detect these temperature changes along the cable with high spatial resolution (around 1 meter) and provide real-time monitoring. This allows operators to identify hot spots or abnormal heating patterns before they lead to failures .Installation and System ConfigurationIn Lithuania, three DTS units were installed for the NordBalt project: one in Klaipeda, Lithuania, and two in Sweden. The system is designed to operate independently at each site, with rack-mounted or compact wall-mounted units. The measurement fibers are either embedded in the cable core or run alongside the cable, depending on whether the section is subsea or onshore .Advantages of Fiber Optic DTSReal-time monitoring of the entire cable length, enabling rapid detection of temperature anomalies.Resistance to electromagnetic interference, which is critical in high-voltage environments.Long-distance capability, with monitoring possible over tens of kilometers without signal degradation.Enhanced reliability and safety, reducing the risk of cable damage and improving operational efficiency .Applications and ImpactThe DTS system in Lithuania ensures that the 700 MW NordBalt link operates safely and efficiently, providing a significant portion of the country's electricity. Beyond subsea cables, similar DTS technology is applied in underground and onshore power cables, allowing operators to simulate failures, detect hot spots, and prevent potential outages . In summary, Lithuania's adoption of fiber optic DTS technology represents a modern approach to power system monitoring, combining high-resolution temperature measurement, real-time data, and robust installation to maintain grid stability and prevent cable failures.