Mathematical Method for Monitoring the Thermal State of the Conductors of Overhead Power Lines

To improve the efficiency and safety (reliability) of power systems operation, system operators carry out calculations and analysis of the steady state modes of power flows of overhead power lines. The accuracy and speed of such calculations depends on the complexity and adequacy of the applied mathematical models and technologies of their use. The accuracy can be increased by taking into account changes in the temperature of power line conductors that occur under the impact of power flows and weather effects. For this purpose, the heat balance equations of the line conductors are added to the traditional power flow expressions. The article discusses the well-known calculation methods for determining the temperature of the network line conductors; their shortcomings are noted. Anew approach is proposed, in which the temperature of the conductors is limited by the voltages of the power system network nodes. They are obtained taking into account the nonlinear heat balance equations. The problem of determining the power flows and temperature of the conductors of the power supply network of a given topology is formulated for known values of the parameters of the lines (at a temperature of 20°C) and functioning generators, including PV type sources, as well as climatic and geographical factors. Using the proposed method, a study of the power flows effect on the conductor temperature of the power system lines for the test circuit of the IEEE 5-bus network was made. The possibilities and usefulness of the proposed method in solving the problems of ensuring the stability and safety of the power system operation, in economic dispatching to compare possible operated and/or planned network schemes, as well as in identifying possible causes of unforeseen line failures are shown. The information obtained during the calculations expands the possibilities of controlling the electrical networks modes.