Influence of AC System Parameters on DC Current Distribution

2019 4th Asia Conference on Power and Electrical Engineering

能源学;电工学

Tong, Xuefang^1 ; Pan, Zhuohong^2

High Voltage Department of China Electric Power Research Institute, No. 143, Luoyu Road, Hongshan District, Wuhan City, Hubei Province, China^1

School of Electrical Engineering, Wuhan University, No.299, Bayi Road, Wuchan District, Wuhan City, Hubei Province, China^2

关键词: Calculation process;    Circuit resistance;    Current amplitude;    Dc current distributions;    Evaluation parameters;    Field-circuit coupling;    Grounding current;    Tower grounding resistances;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/486/1/012141/pdf
DOI  :  10.1088/1757-899X/486/1/012141

来源: IOP

【 摘 要 】

The ground current of HVDC transmission will cause DC bias of transformer in AC system. In order to master the influence of typical AC grid parameters on DC current distribution, a direct field-circuit coupling model of AC and DC power grid is established, and the evaluation parameters of DC current distribution are proposed. The influence of various factors such as the grid density, transformer and transmission line branch resistance, tower-ground wire system on DC current distribution in AC grid are quantitatively analyzed by grid examples. The results show that the denser the grid of a certain voltage level, and the smaller the circuit resistance of transformer and transmission line branch of a voltage level, the larger the DC current of the voltage level and the total DC current of the AC grid. When considering the tower-ground wire system, the DC current entering the AC power grid increases, and the smaller the wire DC resistance and the tower grounding resistance, the more DC current increases. In a line, the tower with the largest grounding current generally appears in the tower 1-4# near the substation with the larger current amplitude. In the calculation process of DC current distribution in large AC grid, ignoring the mutual resistance effect between substations will make the DC current of the AC grid larger, so it is not advisable to neglect the mutual resistance between substations in calculation.