The influence factors of overhead conductors carrying capacity and carrying capacity test

For overhead conductors carrying capacity is one of the essential parameters of power line calculation of transmission capacity. 

Wire carrying capacity value is too high, and the conductor fever is serious, leading to the strength of the conductor loss being bigger, reducing the service life of the wire. If carrying capacity value size, cannot give full play to the economic benefits of a line. The reason should be comprehensive consideration, a good load flow numerical. 

Wire carrying capacity, the size of the main and the resistance of the wire itself, and outer diameter, allow the use of temperature, environment temperature, wind speed, sunshine intensity, and other factors as well as the structure, and surface state of the conductor. Such as the equal cross-section of the steel core aluminum stranded wire, the double layer structure of aluminum wire is better than the single-layer aluminum wire carrying capacity is big, because the double layer structure of aluminum wire ac resistance is smaller.

There are three kinds of carrying current situation of the wire. A current-carrying is no wind no sunshine; 2 it is to have sunshine without wind load flow; 3 it is windy current-carrying with the sun. Ac resistance test, in the constant temperature box sealing, measured current and temperature rise value, painted current temperature rise curve, can obtain no wind no sunshine carrying capacity of the test results. 

With sun and the wind load flow test conditions it is difficult to achieve, therefore can only be based on the special experiment, using calculation methods to implement. The results of these calculations are based on a resistance test.