Abstract: One procedure for non-stationary states analysis of the ACSR conductor heating, that can be applied to the larger cross-sections conductors, is presented in this paper. Mathematical model is formed under assumption that steel reinforcement is isothermal body. Additionally, it is assumed that Joule losses in aluminum part of conductor are concentrated in their inside. System of two differential equations, obtained under these assumptions, is easy to solve numerically. By the introduction of one additional assumption, a simplified mathematical model is formed. Simplified model could be solved analytically, namely, analytical expression for calculation of temperatures in the inside and on the surface of the conductor is obtained. This paper illustrates that although two time constants appear in the simplified model, only one is relevant for the transient heating process.
Key words: ASCR conductor, non-stationary heating, time heating constant.