Electric field calculation and grading ring design for 750 kV four-circuits transmission line on the same tower with six cross-arms

Abstract

The transmission corridors can be effectively saved using 750 kV four-circuit transmission line on the same tower. In order to reduce the corona level, structure optimisation of fittings plays an important role in the transmission line design. In this study, the electric field distribution of 750 kV transmission line on six cross-arms tower was calculated based on finite element method, and the influences of pipe diameter, ring diameter and installation position of the grading ring were analysed. The results show that the increase of pipe diameter can reduce the electric field strength of grading ring while the increase of installation position and decrease of ring diameter are important to protect the end fitting of composite insulator. When using grading ring with the pipe diameter of 100 mm, the ring diameter of 700–900 mm and the installation position of 150–250 mm, the electric field strength can be controlled in a reasonable range. These results can provide references for the grading ring design of 750 kV four-circuit transmission line on the same tower.

Keywords

• finite element analysis
• corona
• composite insulators
• poles and towers
• power transmission lines
• electric fields
• optimisation
• size 150.0 mm to 250.0 mm
• size 700.0 mm to 900.0 mm
• size 100.0 mm
• voltage 750.0 kV
• finite element method
• composite insulator
• end fitting protection
• structure optimisation
• corona level reduction
• cross-arms tower
• electric field distribution
• transmission line design
• transmission corridors
• four-circuits transmission line
• electric field calculation
• grading ring design
• electric field strength
• pipe diameter
• ring diameter
• installation position