高压直流输电圆环接地极屏蔽特性

为研究圆环直流接地极的环间屏蔽特性，考虑电极自阻及实际工程中采用的多点注流方式，基于线电流法，建立了接地极的场路耦合模型，对圆环形直流接地极的地电流溢流进行计算，并对地电位进行求解，然后通过与软件建模仿真结果进行对比，验证了该方法的准确性和可行性。研究结果表明：当双圆环接地极的内环半径增大时，外环对内环的屏蔽作用先增强后减弱，环径比为0．40左右时外环对内环的屏蔽作用最强；相同环径比下，外环半径越大内外环溢流密度比也就越大，外环对内环的屏蔽作用减弱。

Shielding Characteristic of Annular Grounding Electrodes in HVDC Transmission System

To research the shielding characteristic of annular grounding electrodes in HVDC transmission system. Considering the self-resistance and multi current injection points,the field and circuit coupling model based on the line-current method is established. The current overflowing of annular electrodes and the potential distribution on the surface of earth are calculated. Then,the correctness and feasibility of the method are verified by the software simulation. The results illustrate that,When the radius of the inner ring increases,the shielding effect of the outer on the inner first reinforces and then weakens. When the radius ratio is about 0.4, the shielding effect of the outer on the inner first is strongest. At the same radius ratio,when the radius of the outer increases,the current density ratio increases, the shielding effect of the outer on the inner weakens.