Research On Total Electric Field And Body Surface Electric Field During Live Working Under HVDC Transmission Lines

With the rapid development of economy in China, in order to meet the growing electricity demand, it becomes a trend to construct the UHVDC transmission projects which are with a larger transmission capacity and longer transmission distance. But in the operation and maintenance of HVDC transmission lines, the surrounding electromagnetic environment becomes more complex because of the corona effect. One side, it may affect the safety of people who is under the lines, on the other side, it increases the difficulty of live working, even threatens the safety of the workers. Therefore, it is of important significance in calculating the total electric field and body surface electric field under UHVDC transmission lines during operation and maintenanceBased on the control equation of UHVDC ion flow field, this paper studies the total electric field and body surface electric field during live working under UHVDC transmission lines by upstream finite element. And combined with the actual situation of live working, this paper established a simplified model of live working, and then studied the body surface electric field distribution at different locations in live working. The main works are as follows:Firstly, this paper studied the form mechanism of ion flow under UHVDC transmission lines, selected the basic control equations and boundary conditions which are used in solving the ion flow field, and studied the process for solving the Poisson equation and the current continuity equation based on finite element.Secondly, this paper calculated the ion flow field in two-dimensional project using finite element. In particular: selected the key parameters which are necessary to solve the field, and calculated the ion flow field of coaxial cylindrical, through the comparison between the analytical result and calculated result, the algorithm is proved to be correct. And then, based on the actual ±800k V transmission lines, this paper calculated the two-dimensional potential, current density and total electric field, discussed their change under different height.Once again, this paper extended the two-dimensional upstream finite element method to three-dimensional to solve the three-dimensional project. It includes three parts: Extended the two-dimensional upstream finite element method to three-dimensional, and write a program. Calculated and verified the ion flow field in concentric conductor ball using the three-dimensional upstream finite element method. Based on the actual ±800k V transmission lines, established a 3D model of lines, then use the three-dimensional upstream finite element method to calculate and analyze the electric field in different surface, discussed the differences between the three-dimensional result and three-dimensional result.Finally, this paper studied the electric field distribution of body surface during live working under transmission lines. Consider the actual situation of live working, we establish the live working person model and tower model, and then calculated the body surface field in different positions under ±800k V transmission lines using above algorithm, summarized the distribution of the electric field.