高压直流输电接地极溢流特性  

Current Overflow Characteristics of Earth Electrodes for HVDC Transmission System

作　　者：黄渤[1] 吴广宁[1] 曹晓斌[1] 任志超[1] 张龙伟[1] 

机构地区：[1]西南交通大学电气工程学院,四川省成都市610031

出　　处：《电网技术》2013年第4期1174-1179,共6页Power System Technology

基　　金：国家电网公司科技项目(2011-WG-4);铁道部重大专项课题(2011T008);中央高校基本科研业务费专项资金(SWJTU11CX035)~~

摘　　要：为研究接地极型式参数和土壤结构对溢流特性及接地性能的影响规律,考虑电极自阻及多点并联注流方式,建立了基于线电流法的场路耦合模型,对圆环形直流接地极地电流溢流进行计算,并对地电位进行求解,然后通过与实测数据及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:外环半径一定时,极环数增加,接地极的溢流能力降低,接地电阻下降程度趋缓;分流比与环径比近似成正比,内环半径增大时,外环对内环的屏蔽作用先增强后减弱;上层土壤电阻率小于下层土壤电阻率时,上层土壤厚度增大,内外环分流比先减小后增大,上层土壤电阻率大于下层土壤电阻率时,分流比的变化趋势相反;同时,随着上层土壤厚度的增加,上层土壤电阻率对接地性能的影响增强,而下层土壤电阻率产生的影响减弱。To research the influencing regularity of types and parameters of earth electrodes and soil structure on current overflow characteristics and grounding performance of earth electrodes, considering self-resistance of earth electrode and parallel-connected multi-point current-injecting mode, a line-current method-based field-circuit coupled model is built. Using the built model, the ground current overflow of DC circular ring earth electrodes is calculated and the earth potential is solved; then through the comparison of measured data with simulation results, the accuracy and feasibility of the proposed model are verified. Research results show that under constant radius of the outer ring the current overflow ability of earth electrodes decrease while the number of circular ring earth electrodes increases and the decreasing extent of grounding resistance alleviates; the current-shunting ratio is approximately proportional to the ratio of inner ring radius to outer ring radius, and with the increase of inner ring radius the shielding effect of outer ring on inner ring intensifies at first and then weakens; when the resistivity of upper layer of soil is less than that of lower layer of soil, along with the increase of the thickness of upper layer of soil the ratio of current-shunting effect of inner ring to that of outer ring decreases at first and then increases, and when the resistivity of upper layer of soil is higher than that of lower layer of soil, along with the increase of the thickness of upper layer of soil the variation trend of the ratio of current-shunting effect of inner ring to that of outer ring is just the opposite; in addition, with the increase of the thickness of upper layer of soil the influence of the resistivity of upper layer of soil on grounding performance intensifies and the influence of the resistivity of lower layer of soil on grounding performance weakens.

关 键 词：高压直流输电 接地极 溢流特性 分流比 

分 类 号：TM86[电气工程—高电压与绝缘技术]