Calculation of sag changes caused by conductor beating with consideration of insulator string deviation in a transmission line section

Relationships for suspension insulator string displacement and sag changes caused by conductor heating due to transmission line uprating are derived. The formulae are obtained with the aid of linearization of the actual nonlinear “stress-elongation equation” and may be used both for computer program checking and for general analysis of the problem. A criterion for the correct application of the linear approach is presented and numerical examples for accuracy demonstration are given. A number of practical recommendations are given on the basis of the obtained linear relationships.