An improved leader progression model for the analysis of the shielding performance of 1000 kV UHVAC transmission lines

摘要

This paper presents an improved leader progression model (LPM). The model uses the proposed leader inception criterion for the analysis of lightning shielding performance of UHVAC transmission lines. It focuses on the discussion of the leader inception voltage of bundle conductors. The improved LPM is validated on 500 kV EHV transmission lines. The shielding performance of a UHVAC transmission line to be constructed in a Chinese Test Line Project is then evaluated. The results indicate that the power frequency operating voltage and the bundle conductor configuration have a greater influence on the shielding failure flashover rate (SFFOR) of 1000 kV UHV lines than that of 500 kV EHV lines. It is found that the UHVAC line to be built will not cause trip accidents due to shielding failure in flat terrain. In broken terrain, the SFFOR is only 0.0012 times/100 km·year, which is less than the design limit.