Corona Discharge Detection and Electric Field Analysis of Bundle Conductor Spacers in 750 kV Substation

The bundle conductor spacers used in ultra-high voltage (UHV) transmission lines and substations are the key fittings which play the role of supporting bundle conductors. In this paper, ultraviolet imaging technology was used to detect the corona discharge of the two-bundle conductors and spacers in 750 kV substation. The ultraviolet images and visible images of the spacers of different structures were obtained and compared. In order to study the influence of the structure of the spacer on electric field distribution and corona discharge, a three-dimensional model of a certain bay of the 750 kV substation was established by using COMSOL Multiphysics, and the electric field distribution was calculated and analyzed based on finite element sub-modeling method. The results show that the structural parameters and positions of the spacers will significantly influence the characteristics of the electric field and corona discharge, and increasing the chamfer radius of the spacer can obviously reduce the electric field strength. In addition, a newly designed spacer was proposed which can optimize the maximum electric field distribution and may further restrain corona discharge. The work in this paper could provide references for electric field control and corona discharge suppression of the fittings in 750 kV substation.