Software Development for DC Current Distribution in AC Power Grid

In order to analyze the HVDC transmission's earth-return current distribution in AC power grids,an improved theoretical model is set up realizing the Thevenin equivalence of underground networks.A power flow calculation interface is developed to load data of the connection of modern large-scale AC grid.Then the random test method was used to summarize the rules of DC current distribution.The results are gained as follows:the larger the AC grid,the more the DC current distribution is caused;the DC current distribution is increased by towers and overhead ground wires;though the local DC current distribution is increased,the total DC current distribution is suppressed by mitigation methods.The simulation software is suitable for DC current distribution computation and evaluating the mitigation methods,and it provides reference for analysis,forecast,mitigation,and adverse effects of DC current distributions.