Weather-based assessment of the overhead line conductors thermal state

The paper presents a method developed to assess the conductor temperature considering the meteorological conditions on transmission lines route. In order to calculate the conductor temperature the non-steady heat balance equation is used. The terms of this equation are evaluated considering the meteorological conditions and power flow data. Two input data sets are used: forecasted and measured values. Numerical forecasted values are interpolated considering the line assets geographical position. The measured values are interpolated using the geo-statistical Kriging algorithm and the altitude dependence of air temperature and wind speed. The resulting conductor temperature can be used to calculate the conductor sag, the conductor resistance in order to evaluate the thermal rating and the power losses. The method was applied for two existing 400 kV transmission lines in both cases (forecast and measured data) to calculate the conductor temperature and the power losses.