Analysis and Computation of Total Electric Field Under UHVDC Transmission Lines With Drizzle Weather

In order to study the influence of drizzle weather on the total electric field of ultrahigh-voltage direct current (UHVDC) transmission lines, an ion flow field model considering drizzle weather is established. This model calculates not only the positive and negative ions but also the charged tiny water droplets, dust particles, and falling raindrops, enabling accurate simulation of the total electric field in drizzle weather. Meanwhile, the ion flow field model is solved by the improved upstream finite element method. First, the influence factors and mechanism of drizzle weather on the ion flow field of UHVDC transmission lines are studied in this article. Then, the improved upstream finite element method is used to solve the ion flow field under different degrees of drizzle weather. Finally, the influence rule of drizzle weather on the total electric field at ground level is obtained. In this article, the accuracy of the ion flow field model is proved by the measurement data of the ground-level ion flow field of the +/- 800-kV UHVDC transmission line from Chuxiong to Suidong. The research results show that the ion flow field of drizzle weather at ground level is larger than that of sunny weather. With the degree increase of drizzle weather, the peak value and distribution curve of the ground-level total electric field gradually increases. This article has a guiding role for the construction and the safe operation of UHVDC transmission lines considering drizzle weather.