配网小电阻接地系统过电压与人身安全性仿真研究  

Simulation Study on Overvoltage and Personal Safety of Neutral Low-Resistance Grounding System in Distribution Network

作　　者：龙国华 刘衍 彭军海 徐碧川 陈斌 周求宽 LONG Guohua;LIU Yan;PENG Junhai;XU Bichuan;CHEN Bin;ZHOU Qiukuan(Jiangxi Electric Power Testing&Research Institute,Nanchang 330096,China;Yingtan Power Supply Company,State Grid Jiangxi Electric Power Company,Yingtan 335000,China;Ganzhou Power Supply Company,State Grid Jiangxi Electric Power Company,Ganzhou 341000,China)

机构地区：[1]国网江西省电力有限公司电力科学研究院,南昌330096 [2]国网江西省电力有限公司鹰潭供电分公司,江西鹰潭335000 [3]国网江西省电力有限公司赣州供电分公司,江西赣州341000

出　　处：《电瓷避雷器》2019年第5期85-91,98,共8页Insulators and Surge Arresters

摘　　要：随着城市配网电容电流的骤增,小电流接地方式逐渐难以满足电容电流补偿需求,部分地区采用了小电阻接地方式,因此对改造后系统的过电压与人身安全研究很有必要。首先从理论角度总结了现有的几种中性点接地方式的优缺点;其次基于Mayr电弧模型,采用EMTP-ATP软件计算了各种接地方式下系统单相接地弧光过电压;最后结合ANSYS和CDEGS软件计算了小电阻接地系统发生单相接地时故障点的跨步电压并进行评估。研究表明:小电阻接地改造后,系统单相接地引发的过电压显著减小,数值不超过2.42 p.u.;站外单相接地发生时,导线直接接地短路的情况对人身安全威胁更大,可采用电缆线路及减小小电阻阻值来抑制。With the sudden increase of the capacitance current in urban distribution network,the traditional low-current grounding method gradually fails to meet the capacitive current compensation requirements.In some areas,the small-resistance grounding method is adopted.Therefore,it is necessary to study the overvoltage and personal safety of the modified system.Firstly,this paper theoretically summarizes the advantages and disadvantages of current neutral grounding methods.Secondly,based on the Mayr arc model,EMTP-ATP software is used to calculate the system single-phase ground arc overvoltage under various grounding methods.Finally,combining ANSYS and CDEGS software,the step-down voltage at the fault point in the single-phase grounding of the low-resistance grounding system was calculated and evaluated.Research results show that after the low-resistance grounding is adopted,the overvoltage caused by the single-phase grounding is significantly reduced and does not exceed 2.42 p.u.;Directly single-phase shorting to ground which occurs outside the station is more dangerous to personal safety,and can be relieved by using cable and reducing low-resistance.The research results of this paper can provide theoretical support and technical guidance for the application of low-resistance grounding methods.

关 键 词：配网 小电阻 电弧模型 弧光过电压 跨步电压 

分 类 号：TM8[电气工程—高电压与绝缘技术]