Lightning Shielding Failure Investigation by High Voltage Experiments

The lightning shielding performance of shield wires in the fully composite pylon has been verified by experimental methods in this chapter. In order to verify the conclusion obtained by electro-geometric model (EGM) analysis in Chap. 6, a scale model test has been performed. Direct lightning strikes to phase conductors are simulated by electrical discharges to scale phase conductors with fast-front and slow-front impulses in the high voltage lab. Shielding failure rate (SFR) is obtained by interpreting the ratio of number of discharges to scale phase conductors to the total number of discharges. Additionally, the maximum shielding failure current is obtained by scale model tests. Comparing results developed by theoretical method—electro-geometric model (EGM) and experimental method-scale model test, it proves that these two methods verify each other and support each other’s application to the lightning shielding investigation in the innovative fully composite pylon. A conclusion can be drawn that, as regards to protection from direct lightning strikes, shield wires in the fully composite pylon can prove acceptable lightning protection for overhead lines.