ENERGY INDUSTRY System Components
Discover Raman-Based Temperature Measurement
The RTTR cable monitoring system consists of a temperature measurement device, the Distributed Temperature Sensing (DTS), and our visualization and RTTR calculation software, a current interface for reading in the current data, an optical fiber for temperature measurement and network interfaces for data communication.
Optical Fiber
For seamless temperature measurement, the fiber optic cable must be positioned along the power cable, serving as a spatially distributed temperature sensor; an immense advantage over point-based sensors. Due to its small dimensions, the fiber optic cable can be integrated into the sheath of the power cable or placed separately in close proximity (e.g., in the interstitial area in a triangular configuration). The optical fiber provides several advantages in application. The optical measurement signal is immune to electromagnetic fields, ensuring high stability. The fiber optic material is an electrical insulator, meaning it is non-conductive. There are no potential differences (galvanic isolation) between the DTS device and the measurement site. Moreover, as a passive sensor, the optical fiber does not influence the temperature measurement (unlike electrical sensors, it does not generate self-heating), allowing for highly accurate temperature readings.
Distributed Temperature Sensing (DTS) – The Temperature Measurement Device
DTS uses the Raman Effect for temperature measurement. During each measurement interval, DTS emits a high number of short laser light pulses, which propagate along the fiber optic cable. This laser light interacts with the molecules in the glass at every point along the fiber. Due to the amorphous structure of the optical fiber, the light undergoes scattering at each point, known as Rayleigh scattering. Additionally, the varying ambient temperatures along the length of the fiber induce thermally excited molecular vibrations within the glass material, creating an additional scattering effect called Raman scattering. A portion of this Raman scattering travels back to the temperature measurement device. The intensity change in the Raman scattering serves as a direct measure of temperature change at each point along the fiber. By measuring the travel time of the Raman scattered light from different locations along the fiber to the temperature device, the system can pinpoint temperature values to the exact meter.
This makes it possible to measure temperature continuously along the fiber—and thus along the power cable—both spatially and temporally. Hotspots along the power cable can be located with meter-level precision.
This method resembles a radar echo but has the advantage of simultaneously measuring all points along the cable. Power cable routes up to 70 kilometers in fiber optic length can be monitored with high spatial accuracy within a meter range and absolute temperature accuracy within a few degrees Celsius.
RTTR Software – Calculation and Visualization Software
The core of our cable monitoring system is the RTTR software, also known as Dynamic Cable Rating (DCR). This proprietary calculation and visualization software precisely calculates the conductor temperature at every point within the cable system and presents the results in a clear, graphical format for the user.
Based on local temperature measurement data, the software first locates hotspots. To determine conductor temperatures and the maximum load reserves of the cable system, it employs complex cable and route models that account for the current load, load history, cable structure, cable laying layout (longitudinal), and cross-sectional profiles of the cable route. These data are then used to calculate load reserves for each power load in real time.
The RTTR calculation results are typically transmitted to the grid operator every 15 minutes, allowing the cable operator to adjust and optimize the load for steady-state, dynamic, and pulsed-load operations - ensuring reliable system operation.
When provided with power load profiles from sources such as wind farms or solar plants, the RTTR software calculates and forecasts the maximum allowable current, considering the maximum permissible conductor temperature. The calculations reveal real-time load reserves of the cable system, enabling optimal load management for your cable infrastructure.
Extended RTTR Calculation Methods
- Parallel cable systems with different power loads
- Parallel cable systems with varying cable configurations (flat and triangular layouts)
- Trench profiles with arbitrary side ratios
- Cable surroundings with varying embedding materials
- Calculations independent of prior load and load factor
- Load forecast calculations in steady-state operation (IEC 60287), dynamic operation (emergency operation IEC 60853), and pulsed load operation
- VDE0276: Current-carrying capacity, conversion factors
- VDE0298: Soil drying
Two modules are integrated into the software for graphical representation and long-term analysis of the data.
VISCOM Power Cable
The VISCOM Power Cable software enables users to visualize the measured current and temperature data, as well as the calculated RTTR data, in an application-oriented format.
VISCOM Analyzer
The VISCOM Analyzer is used to display spatial and temporal measurement data over extended periods of time. This software allows for targeted analysis and comparison of data, with flexible selection of the desired time range.
Additional Components
The RTTR cable monitoring system includes additional components such as a control cabinet, server and screen, interfaces, and connection cables. The turnkey system can be provided either as a stationary setup in a control cabinet or as a mobile unit, depending on customer requirements and needs.
Experience the RTTR Cable Monitoring System On-Site
We offer on-site presentations of our RTTR cable monitoring system, providing you with a hands-on understanding of its functionality.
Having Questions?
Contact us. Our team is happy to assist you.
Phone: +49 2204/84–2770
Mail: info@osscad.de