The effect of the variation of the electric contact resistance of the conductor joints during operation on the reliability of the overhead lines

Apart from the impact or vibrating forces due to wind actions, the operating life period of the bolted joints used in overhead lines is affected by mechanical, thermal and chemical factors acting simultaneously on the joint which depend not only on the type of joint used but also on the temperature and pressure applied to the joint in a given atmospheric condition. The analytical procedure discussed by the authors gives a suitable simplified solution to this complicated problem based on experimental model tests which enable the designer to make a comparison between the operating life period of the joint under different operating conditions. The authors discuss the importance of using bolts with suitable locking nuts to withstand the forces applied to the joint due to wind actions. They also present the advantage of shielding the joint against solar radiation to reduce the surface of contact temperature rise