Dynamic Model of Overhead Power Transmission Lines Charging Capacity Taking into Account Meteorological Factors
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Abstract
The article investigates the impact of meteorological conditions on the charging capacity of overhead power lines and develops an approach to monitoring the condition of wires in changing meteorological conditions. It is shown that changes in temperature, wind pressure, and ice formation cause variations in the sag of the wire, which leads to a change in its spatial position and, accordingly, the charging capacity of the line. The results of mathematical modeling are presented, which allowed to perform quantitative assessment of the influence of temperature fluctuations and icing on the capacitive parameters the main lines. It has been established that temperature changes in the range from –30 °C to +70 °C can cause a change in charging capacity of approximately 1 %, and the formation of an ice layer up to 40 mm thick can cause an increase in capacity of up to 1.5 %. Such deviations are insignificant for distribution networks, but can be critical for long overhead lines of ultra-high voltage. Refined mathematical models have been developed that take into account the influence of wire sag on charging capacity, as well as analytical relationships between sag, temperature, and the angle of inclination of the wire in the span. Particular attention is paid to the inclinometric approach as one of the most efficient and technologically simple methods of monitoring the condition of the wire. Almost linear relationship has been established between the angle of inclination of the sensor and the sag for spans ranging in length from 100 to 450 m, which makes it possible to indirectly determine both the temperature of the wire and the mass of ice deposits. Based on the obtained dependencies, algorithms have been developed for the operation of the monitoring device, which implement two modes: continuous monitoring of sag and monitoring only in the temperature range at which icing deposits are observed.
