The University of Southampton

RoCiT - Ratings of Cables in Tunnels

HV cables in a tunnel
Modelling and Simulation, Environmental modelling
National Grid plc

The RoCiT project follows on from a number of previous projects (including FEAR - finite element analysis for cable ratings) and examines the methods used to derive current ratings for high voltage cables (132kV and above) installed in tunnels. Such installations are becoming increasingly desirable for the operators of power transmission networks, particularly for supplying power to densely populated urban areas. The project has developed improved circuit rating algorithms through removing limiting assumptions in the existing Electra 143 methodology, while making use of numerical modelling tools (including FEA/CFD analysis) and operational data from existing cable systems. This has led to a more flexible model which permits calculations where multiple different cable circuits, operating on different load cycles, exist within the same space. The results obtained assist cable engineers to provide the optimum current rating ratings for these expensive assets. Risk to the cable asset through overheating is minimised, but not at the expense of under utilising the cable circuit.

Primary investigators

Secondary investigator


  • National Grid plc

Associated research groups

  • Electronics and Electrical Engineering
  • Electrical Power Engineering
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