Study on electric field distribution of cage-type rigid jumper for 500 kV AC transmission lines

Cage-type rigid jumper is an essential connecting component on extra-high voltage (EHV) transmission lines, but with a more serious distortion of surface electric field than straight bundled conductor due to its complex structure and bending. In order to optimize the structure for a jumper with less corona loss, distribution of electric field on the surface of such a jumper is modeled and studied. In this paper, three-dimensional finite element method is applied to simulate the electric field distribution on the surface of quad bundle cage-type rigid jumper on 500kV AC transmission lines; the external diameter of and space between sub-jumpers are varied to observe the changes in electric field as a function of jumper structural dimensions. Three conclusions are obtained: the maximum intensity of electric field increases with the whole curvature of the jumper; the maximum intensity of electric field decreased with the external diameter of sub-jumpers; the intensity as a function of sub-jumper spacing appears to be a U profile. These conclusions could provide reference to the design of extra-high voltage and ultra-high voltage transmission lines.