A Stable and Efficient Hybrid Method by Imposing Kapzov Assumption Explicitly for the Space Charge Problem of the HVDC Transmission Lines

To overcome the problem of the inefficiency and oscillation when applying the secant methods to impose the boundary conditions, this study presents a hybrid method for the space charge problem of the HVDC transmission lines. The proposed method imposes the boundary conditions by solving the dimension-reducing problems defined on the field lines, which has taken the nonlinear relations between the space charge and the electric field into consideration. Numerical experiments show that the proposed method only takes two steps to obtain the solutions within the error tolerance and the whole procedure is much stable than the secant based methods. The proposed hybrid method can significantly reduce the computation time of the space charge problem.