US 12,455,253 B2
Estimating the thermal resisitivity of soil surrounding an underground cable
Ola Thyrvin, Karlskrona (SE); and Vilhelm Rydén, Karlskrona (SE)
Assigned to NKT HV Cables AB, Lyckeby (SE)
Filed by NKT HV Cables AB, Lyckeby (SE)
Filed on Nov. 11, 2022, as Appl. No. 18/054,755.
Claims priority of application No. 21208054 (EP), filed on Nov. 12, 2021.
Prior Publication US 2023/0152260 A1, May 18, 2023
Int. Cl. G01N 25/18 (2006.01); G01N 33/24 (2006.01)
CPC G01N 25/18 (2013.01) [G01N 33/24 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for estimating the thermal resistivity of soil surrounding an underground cable, the method being performed by a thermal resistivity estimating unit and comprising:
obtaining a first temperature (Ts) from a first temperature sensor at an exterior surface of the cable,
obtaining a second temperature (Ta) from a second temperature sensor placed in the soil at a distance from the cable,
obtaining a measurement of current (Ic) transmitted in the cable, and
estimating the thermal resistivity of the soil based on the first and the second temperatures (Ts, Ta) as well as on the current measurement (Ic),
wherein the estimation of the thermal resistivity of the soil is based on an estimate of the temperature at the exterior surface of the cable caused by power losses in the cable when the measured current (Ic) is running in the cable.