Mitigation of Magnetic Flux Density of Underground Power Cable and its Conductor Temperature Based on FEM

Abstract

This article proposes using a metallic plate to be installed above the underground power cable route to mitigate the maximum cable conductor temperature and the ground surface magnetic flux density surrounding the cable route and underground cable de-rating factor. The article presents a case study containing a single-circuit 145 kV, three-phase individual cables in flat formation. The impacts of the mitigation plate dimensions such as plate width, thickness, the distance between the underground cables and the plate used in the mitigation, and the plate material are investigated. Three kinds of materials are examined in this article, namely aluminum, steel 100, and steel 500. Moreover, the optimal design dimensions of the metallic plate for the case under study were estimated. It is concluded that the shielding factors of the magnetic flux density and cable core temperature with aluminum are greater than steel 100 and steel 500. In addition, the de-rating factor, which is the ratio of the current capacity of the underground cable with shielding plate and that without shielding plate at the same cable core temperature, is increased to be 1.28 with the use of shielding Aluminum plate, rather than 1.18 and 1.17 in case of using Steel 500 and Steel 100 shielding plates, respectively. Finally, the proposed algorithm was validated by comparing its results with the experimental measurements obtained by the others, indicating good agreements.

Keywords

• Underground cables
• de-rating factor
• magnetic flux density
• magnetic shielding factor
• mitigating shielding factor of temperature
• shielding plate