REAL-TIME TRANSIENT TEMPERATURE COMPUTATION OF POWER CABLES INCLUDING MOISTURE MIGRATION MODELLING

Abstract –A conceptually simple and robust methodol-ogy for real time monitoring and transient cable rating is offered. The paper outlines a general approach suitable for a wide range of application, and also provides a specific but typical example of its implementation. The main ad-vantage of the approach is its inherent ability to cope with changes in the thermal properties of the cable or its envi-ronment. A major challenge, particularly with transient rating, is to incorporate moisture migration modelling, which refers to the growth of a dry zone around the cables when they exceed a critical temperature. A new approach to this problem is presented theoretically and substantiated with both simulations and measured results. In addition, sea-sonal changes in the nominal properties of the cable envi-ronment can be incorporated in the algorithm, which oper-ates in real-time and is computationally light. It is hoped that the collection of techniques embodied in the text and accompanying figures will be of interest and service to the cable rating community in the ongoing en-deavour to further improve both the efficient utilisation and reliability of power system equipment