29-08-2017, 11:20 AM
Insulation cords, used for the suspension of overhead transmission lines, are one of the most important parts of transmission lines, since they used to support electrical conductors and protect them from the ground conductor or other conductor as well as provide the necessary mechanical supports for transmission lines against the worst mechanical loading conditions likely.The number of insulation units consisting of the suspension insulation chain depends on the operating voltage of the upper transmission line.The calculation of the electric field and the distribution of voltage in and around high voltage isolators is a very important parameter for the design of insulators. The high levels of the electric field are possibly responsible for the audible noise, the electromagnetic pollution, the partial discharge and the premature aging of the insulation. The assignment of the electric field distribution in a series of insulators is useful as it is an indication for the propagation of fl amever. The Hampton criterion shows that fl ashover can not occur if the surface electric gradient is sufficiently low. Flaphover effects on isolators can cause a transmission system to rupture. In addition, knowledge of the electric field is useful for the detection of defects in insulators.