Calculation Analysis and Improvement Measures of Lightning Strike Trip Rate for Collection Lines of Wind Farm in High Altitude Mountain Area

At present, lightning tripping has become a serious threat to the safe operation of high-altitude mountain wind farms. This paper completes the risk assessment and analysis of the winding trip of the whole collection line by establishing a three-dimensional electrical geometric model that can consider the influencing factors such as complex terrain, tower structure and line sag in mountainous areas; Then, the electromagnetic transient simulation software is used to model and calculate the counterattack trip risk of collector line; Finally, the lightning trip risk of the whole collector line is evaluated and the improvement measures are put forward. The calculation results show that after correcting the insulator flashover voltage in high altitude areas, the calculated direct lightning trip rate of the collector line of the wind farm is 5.4061 times /100km.year, which is basically consistent with the 5.0158 times /100km.year converted from the statistical data of lightning trip fault information of the wind farm; The tripping rate of wind power collection line in mountainous area is obviously affected by the ground inclination angle. The valley terrain within the span will make the towers on both sides prone to lightning flashover; The lightning protection effect of more than 94.74% of the poles and towers of the collection line is not ideal. Among them, the lightning flashover risk of the poles and towers caused by lightning counterattacks is the highest. Counterattack tripping has become the biggest threat to the safe operation of the collection line of a wind farm in mountainous areas; It is difficult to effectively reduce the counterattack trip rate by reducing the tower grounding resistance and increasing the insulation level. A lightning arrester can be selected as the main lightning protection measure.