Discussion on Lightning Protection Angle of Downhill Side of Mountain Transmission Line

摘要

Currently, the most single circuit suspension tower is symmetrically arranged, which makes the shielding failure rates of the two side conductors are very different when transmission lines is located on mountainous area. Aiming at the problem， the shielding failure trip-out rates under different slope angles, different protection angles and different ground flash density based on universal design tower 2A1-ZB2 are researched, and several suggestions are given according to the shielding failure trip-out rates of typical tower in standard. The protection angle locating on the downhill side needs to be reduced when slope angle is bigger than 20° and lightning area is B2 grade and over, the shielding angle is set to 5° when in B2 and C1 gradelightning area, is set to 0° when grade is C2, and is set to -5°when grade is D1 or D2.