Heat Dissipation in Variable Underground Power Cable Beddings: Experiences from a Real Scale Field Experiment

Christoph Verschaffel-Drefke,Volker Hinrichsen,Ingo Sass,Constantin Balzer,Markus Schedel

doi:10.3390/en14217189

Abstract

To prevent accelerated thermal aging or insulation faults in cable systems due to overheating, the current carrying capacity is usually limited by specific conductor temperatures. As the heat produced during the operation of underground cables has to be dissipated to the environment, the actual current carrying capacity of a power cable system is primarily dependent on the thermal properties of the surrounding porous bedding material and soil. To investigate the heat dissipation processes around buried power cables of real scale and with realistic electric loading, a field experiment consisting of a main field with various cable configurations, laid in four different bedding materials, and a side field with additional cable trenches for thermally enhanced bedding materials and protection pipe systems was planned and constructed. The experimental results present the strong influences of the different bedding materials on the maximum cable ampacity. Alongside the importance of the basic thermal properties, the influence of the bedding’s hydraulic properties, especially on the drying and rewetting effects, were observed. Furthermore, an increase in ampacity between 25% and 35% was determined for a cable system in a duct filled with an artificial grouting material compared to a common air-filled ducted system.

Highlights

IntroductionThe reliable function of the electrical energy supply is one of the most important parameters for both an improved quality of life of the population and for the economic growth of countries worldwide [1]
For reasons of acceptance or for reasons related to structural engineering, the majority of these expansions cannot be executed as pure overhead transmission lines but need to be conducted using underground power cables [4,5,6]
To investigate the heat dissipation processes around buried power cables in real scale and with realistic electric loading, a field experiment consisting of a main field with various cable configurations laid in four different bedding materials and a side field with additional cable trenches for thermal enhanced bedding materials and protection pipe systems was planned and constructed

Summary

Introduction

The reliable function of the electrical energy supply is one of the most important parameters for both an improved quality of life of the population and for the economic growth of countries worldwide [1] For this purpose, the distribution systems of electrical energy require a maximum transmission capacity to work economically efficiently as well as to ensure a maximum supply safety. The distribution systems of electrical energy require a maximum transmission capacity to work economically efficiently as well as to ensure a maximum supply safety To guarantee these qualities, the electric grid infrastructure has to be extended or modified in many countries within the decades [2,3]. For reasons of acceptance or for reasons related to structural engineering, the majority of these expansions cannot be executed as pure overhead transmission lines but need to be conducted using underground power cables [4,5,6]

Results

Discussion

Conclusion