Abstract
In order to determine the upper limit value of charging currents on overhead transmission lines, the transition of conductor temperature by charging currents, i.e. conductor thermal hysteresis should be evaluated correctly at first.
This paper shows that the conductor thermal hysteresis can be evaluated more correctlythan the accepted manner, by means of long-term tracing the conductor temperature in the constant charging currents based on the data by meteorological observatory.
In other wards, the conductor thermal htsteresis based on the data by meteorological observatory is evaluated excessively than the actual thermal htsteresis. However accumulated conductor thermal htsteresis based on the meteorologicaldata during past 30 years is a little, and it shows that the value of conductor deterioration is drastically less than the present supposed value. (40% of present supposed value)
Accordingly if the long-term evaluation of conductor thermal hysteresis based on the data by meteorological observatory is applied, the upperlimit value of charging currents can be increased sufficiently from point of view of conductor deterioration.
