THERMO-STRESSED STATE OF A HOLLOW POLYMER DIELECTRIC CYLINDER

The paper presents a mathematical model describing the distribution of stresses in a hollow cylinder caused by a one-dimensional steady temperature field occurring at an assigned fixed difference of electrical potentials on the surfaces of a cylinder made of polymer dielectric. A quantitative analysis of the model makes it possible to identify the effects of temperature dependences of the specific electrical resistivity, thermal conductivity coefficient, and mechanical characteristics of the dielectric material on the thermo-stressed state of the cylinder. The model reflects the conditions of work of the dielectric layer of a single fiber high DC-voltage cable. Estimates are given of the conditions for the occurrence of a thermal breakdown of a dielectric cylindrical layer and of the cylinder's boundary state of stress which occurs in the case of planned or emergency nullification of electric potential difference. The results of such analysis can be useful for identifying possible areas of application of polymer dielectrics in various electrical devices.