Refined analysis of the limit modes of overhead power lines

Abstract

The article analyzes the limiting modes of overhead power transmission lines in terms of heating and voltage losses. The equations linking the wire temperature, voltage loss, load power, cooling conditions and line parameters are obtained. Depending on the length, three characteristic regions can be distinguished in which the limiting modes are determined either only by heating, or only by voltage loss, or both. A combined limit mode is considered separately, in which the wire temperature and voltage loss simultaneously assume the maximum permissible values. New refined criteria for assessing the admissibility of the line mode have been obtained. As an example, the AC-240 line with a 220 kV voltage of varying length is considered, for which a number of dependencies characterizing the areas of existence and conditions for the occurrence of limit modes are constructed.