Application of Improved Electrical Geometry Model in Calculation of Lightning Shielding Failure-Caused Trip-out Rate of 1 000 kV Power Transmission Line
Shan Zhixiang · Power System Technology · 2010
Advantages and disadvantages of three existingmethods to calculate lightning shielding failure are analyzed. The electrical geometry model method is improved to solve the coordinates of intersection point of striking distance curves while the incident direction of is perpendicular to ground; according to the change of incidence angle of lightning current, then the intersection point is mapped to different geometric spaces; and then based on actual striking distance curves the coordinates of intersection point are modified to solve the trip-out rate due to lightning shielding failure. Calculation results show that the improved electrical geometry model method is more accurate than traditional methods. Finally, applying the improved method the influences of ground wire protection angle, tower height, cross arm length of middle phase and layer space on lightning shielding failure-caused trip-out rate of 1 000 kV power transmission line are analyzed.