Real Time Thermal Rating (RTTR) or Dynamic Cable Rating removes all uncertainty left by the DTS. The DTS measures the real time temperature at the sheath or jacket of a cable. The sheath temperature gives a good idea of the temperature of conductor, but unless an accurate model for the conductor is provided there will be some uncertainly left. The uncertainty is small during steady state operation, but it could be (very) large during an emergency situation. The following figure illustrates the temperature of the jacket and conductor during an emergency situation.
One can appreciate that while the temperature difference between the jacket and the conductor can be small in steady state. However, moments after the onset of an emergency situation the temperature difference could be very large. The reason is that cable insulation has a large inertia and therefore the heating of the conductor can only be detected at the jacket several minutes (to hours) later. Additionally, the temperature difference changes with the loading level. The temperature difference is larger for larger loading levels.
- Real Time Thermal Rating (RTTR) – Dynamic Cable Rating
- Essential for Smart Grid: Distributed Temperature Sensing for Real Time Power Cable and Overhead Line Monitoring
- Real-Time Cable Thermal Rating (RTTR) went on-line at a tunnel near Stockholm, Sweden