LIOS EN.SURE Long Range Power Cable DTS System

The LIOS EN.SURE Long Range power cable DTS system is a unique optical fiber-based temperature measurement system designed to monitor underground T&D power cables and overhead transmission lines over long distances. The Long Range DTS system continuously monitors and predicts cable load and core temperature over single-ended lengths of up to 70 km.

With the increasing demand for electricity and new renewable energy resources, managing power networks becomes more complex, and operators are faced with higher demands for up-time and challenging grid load balancing.

The industry-leading range of 70 km reduces cost and installation complexity as fewer DTS units are needed per installation. Thanks to an internal fiber switch, the LIOS EN.SURE Long Range power cable DTS system can handle up to 16 fibers and consequently 16 separate power cables.

The EN.SURE Long Range DTS system measures the temperature of a power cable with an accuracy better than 1°C and a strain down to 2 µε over distances up to 70 km. This ensures precise hotspot location and fast detection of mechanical disturbances of the cable (e.g. boat anchors, excavator digging, etc.).

Moreover, the LIOS EN.SURE DTS data is used to calculate the cable conductor temperature in real-time and to predict cable load (Real-Time Thermal Rating), thereby allowing the operator to run the cable above nominal capacity for peak emergency situations.

A Mean Time Between Failures of 40+ years

Reliability is critical when it comes to DTS systems. With 5,000 DTS systems in operation, we have calculated a remarkable MTBF of 40 years.

Made from Telcordia-rated components, passive cooling, and no moving parts, our DTS systems are basically maintenance-free. The self-diagnosing features free you from worrying and allow you to focus on other important tasks.


  • Industry-leading 70 km range
  • Superior hotspot detection along the whole sensor cable
  • Flexible and direct connection to management systems such as SCADA
  • Up to 16 individual channels enabling one unit to cover complex infrastructure
  • Temperature resolution better than 1°C
  • Maintenance-free and simplified outdoor installation capability
  • Real-time Thermal Rating (RRTR) software calculation engines based on IEC, AEIC, and IEEE standards
  • Mean Time Between Failures of 40+ years

When choosing a long-range power cable DTS system from NKT Photonics, you not only buy the most reliable DTS hardware on the market but also our decade-long expertise in power cable and transmission line temperature monitoring.

We partner with you from the initial planning phase, over installation and commissioning and when everything is running, we can offer service agreements to ensure your DTS solution operates smoothly for years to come.

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Distance ranges of EN.SURE DTS Models

The LIOS EN.SURE Long Range power cable DTS system comes in five different range configurations to fit a range of different configurations. If you need a range below 30 km, we recommend our standard range EN.SURE DTS system.

LIOS EN.SURE - 300, -400, -500, -600, -700 30 km, 40 km, 50 km, 60 km, 70 km

Optical data

Optical Channels (internal) 1, 2, 3, 4, 6, 8, 9, 12 or 16
Fiber Configuration No loop or termination required
Optical Connector (s) E2000 / APC
Fiber types Single-mode 9/125, e.g. ITU-T G.652, G.655 or G.657
Laser Classification Class 1M (IEC60825-1) eye-safe wavelength

Measurement Performance*

Sampling Interval 0.25, 0.5 or 1 m
Spatial Resolution (availability depending on distance) 1, 2, 3 or 5 m
Temperature Resolution, minimum <0.1 °C
Temperature Resolution @ 10 dB Optical Loss <1°C
Temperature Accuracy 2°C**
Measurement Time 1 to 20 min

*Measurement performance parameters are interdependent
**After calibration on a loose fiber without strain

Data Storage/Communication/Interfaces

Internal SSD Storage 8, 16, 32 or 64 GB
Communication Interfaces 2x Ethernet TCP/IP, USB, (optional: WLAN, GSM)
Communication Protocols (options) XML, MODBUS, DNP3, IEC60870, IEC 61850
Programable Inputs/Outputs 4/10
Fixed Outputs Collective fault and alarm
I/O Board (optional)* 4 inputs/12 outputs
Analogue Sensors Interface Board (optional)* 4x Pt100, 2x 0(4)-20 mA and 2x 0-10 V
Analogue Outputs (optional external module) 4 - 20 mA

*2 optional boards can be installed

Mechanical Data

Rack Space 19-inch rack, 3 height units
Dimensions HxWxD 13.3 x 43.9 x 40.3
Weight 15 kg

Environmental Conditions

Power Consumption, max. (DC/AC options) 40 W / 45 W
Operating Voltage (DC-1 option) 12 ... 24 V DC (-15%/+10%)
Operating Voltage (DC-2 option) 24 ...  48 V DC (-15%/+10%)
Mains Voltage (AC option) 100 ... 240 V Ac 50 ... 60 Hz / 110 ... 220 V DC (-15%/+10%)

Conformity to Standards

Electrical Safety IEC/UL 61010-1, LV directive 2014/35/EC, CAN/CSA-C22.2
EMC* EN61326-1, EN61000-62,3 -4-2, 3, 5, 5, 6, 8, 11, -3-2, 3, FCC 47 CFR Ch. 1 part 15
Hazardous Substances, waste RoHS directive 2011/657EC, WEE directive 2002/96/EC
Environmental Testing* IEC 60068-2-6, 14, 27, 30
Environmental Safety (IEC 61508)* Hardware design compliant to Safety Integrity Level SIL2
Explosion Safety (option)* EX II (1) [Ex op is T4 GA] IIC/II 81) [Ex op is Da] IIIC/I (m1) [Ex op is MA]

*Qualification in process