engleski

Measurement of Soil Thermal Properties by Spherical Probe

The thermal resistivity of the soil surrounding a power cable is a very important factor in evaluating the load-carrying capability of underground cable. This paper presents a method for measurements of soil thermal properties with spherical probe along the cable installation routes. On the base of two port network analysis equations for temperature response of hollow spherical probe are obtained. The paper offers a mathematical model for calculation the soil thermal parameters including the related standard deviations using the least square method. Propagation time of thermal flux is calculated and it is shown that transient stage of spherical probe can be used for measurements in infinite as well as limited samples of soil. Thermal self capacity and contact thermal resistance between probe and surroundings are taken into calculations. Realization of probe with electrical heater and temperature detector as well as additional measuring devices are described.

Soil thermal properties; spherical probe; temperature; thermal resistivity

nije evidentirano