Study on bird damage risk region of ±400kV DC transmission line

Bird damage is one of the most important factors that threaten the safety and stability of DC transmission line. In order to solve the gap breakdown problem caused by bird damage, this research provides the method of figuring out the risk region of tower. The ±400kV tangent tower model was based on altitude correction of discharge voltage in high altitudes. Three-dimensional finite element model was used to calculate the potential of bird streamer and nest material. The analysis contained three stream ways of foreign objects which were in vertical direction, inclined direction and hang from cross arm of tower. Potential distribution around insulator string and foreign object was calculated. Numerical results were presented for variations of length, location and angle when foreign objects streamer. By utilising the criterion of the breakdown voltage of air gap in high altitude areas, risk region of tower was able to divide. The result shows that a long enough bird streamer can cause gap breakdown in risk region of tower. The research on bird damage risk region is expected to provide a reference for the prevention work of bird damage.