Internship/Graduation Project – Continuous Power Cable Temperature Estimation Based On Propagation Time Measurements

  • Internship
  • Anywhere

Website DNV-GL

Smart Cable Guard (SCG) is an online multi-functional monitoring system for MV power cable networks. The system has two unique functions: 1) detect and locate weak spots based on partial discharges (before they result in a fault causing a power outage) and 2) detect and locate faults (=full breakdowns) in underground power cables. Want to know more about Smart Cable Guard? Click here!

We continuously strive to improve the SCG system, not only by improving existing functionality, but also by adding completely new functions. One of the ideas is a fundamentally new method to continuously estimate the (bulk) cable temperature based on cable propagation time measurements. The propagation time is known to vary with the cable temperature, which in turn is a function of the load current, ambient temperature and other conditions in the environment around the cable. By measuring how the propagation time varies over time, relative variations in cable temperature can be estimated. The idea is to combine these continuously measured and estimated relative cable temperature variations with a thermal cable model to determine the absolute cable temperature. For an  accurate estimation, the model must consider any other factors influencing the relation between variations in cable temperature and in propagation time, for example insulation material and soil properties, such as thermal conductivity and heat capacity. Further, the cable temperature is also influenced by the ambient temperature and other weather conditions.

Having real-time insight in the cable temperature has several potential use cases:

1. Help solve congestion issues in the MV network. Knowing actual cable temperatures gives insight in the actual maximum load that a specific cable can handle.
2. Provide better insight into the thermal aging of cables. Instead of relying on estimates of
average loads, the actual cable temperatures can be used. These cable temperatures can then be used as input to models of cable aging and remaining life, giving better insight in the cable condition.

The goal of this project is to investigate how continuously measured cable propagation times can be combined with ambient temperature recordings and other external information to continuously calibrate a thermal model and determine, in real-time, the absolute values of cable temperature with good accuracy. The project will involve literature study, creating a dynamic thermal model of a power cable and it environment, analysing measured propagation times (gathered by the large installed base of SCG systems), fitting the model to the measurements, and verification of results.

Start date: any time between now and mid-2021
Duration: 6-12 months
Prerequisites: background in any engineering field with fundamentals in thermodynamics

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