高压电缆接地电流的计算及其影响因素分析
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摘要
单芯高压电缆金属护套接地电流过大会导致其护套上产生大量附加损耗,降低电缆载流量,缩短电缆使用寿命。为分析电缆线路金属护套中的接地电流,建立了单芯电缆交叉互联接地方式下接地电流的数学计算模型,并编制了相应的计算程序,通过与实测值比较,验证了该计算程序能准确得到实际电流值。在此基础上,分析了单芯高压电缆金属护套接地电流与其接地电阻、护套参数以及大地电阻率等影响因素的关系。结果表明,电缆接地电阻对接地电流的影响较大;在工程实际范围内,金属护套参数对接地电流值影响不大;只有当大地电阻率很低时,接地电流值才对大地电阻率比较敏感。研究结果为高压电缆运行维护提供了理论依据。
Excessive grounding current on metal sheath of single-core high-voltage cable will bring massive additional loss to the cable, which reduces the cable′s current-carrying capacity and safe operation lifetime. In order to analyze the grounding current in metal sheath, a mathematical model of grounding current calculation and relevant program are established aiming at single-core high-voltage cables in cross-bonding grounding mode. The calculation results prove that the program is competent to reflect actual grounding current. Furthermore, the relationship between grounding current and its influencing factors such as grounding resistance, sheath parameters and earth resistivity is analyzed. The results of analysis indicate that the grounding resistance has a great influence on the grounding current, while in actual engineering the parameters of metal sheath do not. Grounding current is sensitive to earth resistivity only when the value of earth resistivity is low. The research conclusions provide a theoretical basis for the operation and maintenance of high-voltage cables.
Excessive grounding current on metal sheath of single-core high-voltage cable will bring massive additional loss to the cable, which reduces the cable′s current-carrying capacity and safe operation lifetime. In order to analyze the grounding current in metal sheath, a mathematical model of grounding current calculation and relevant program are established aiming at single-core high-voltage cables in cross-bonding grounding mode. The calculation results prove that the program is competent to reflect actual grounding current. Furthermore, the relationship between grounding current and its influencing factors such as grounding resistance, sheath parameters and earth resistivity is analyzed. The results of analysis indicate that the grounding resistance has a great influence on the grounding current, while in actual engineering the parameters of metal sheath do not. Grounding current is sensitive to earth resistivity only when the value of earth resistivity is low. The research conclusions provide a theoretical basis for the operation and maintenance of high-voltage cables.
引文
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[16]杜伯学,李忠磊,张锴,等.220 k V交联聚乙烯电力电缆接地电流的计算与应用[J].高电压技术,2013,39(5):1034-1039.DU Boxue,LI Zhonglei,ZHANG Kai,et al.Calculation and application of 220 k V crosslinked polyethylene power cable grounding current[J].High Voltage Engineering,2013,39(5):1034-1039.
[17]ZHENG Jiankang,SU Xiaoting,ZHENG Linzi,et al.Research and analysis of multi-loop high-voltage cable metallic sheath current circulation calculation[J].Power Electronics,2017.
[18]刘英,王磊,曹晓珑.双回路电缆护套环流计算及影响因素分析[J].高电压技术,2007,33(4):143-146.LIU Ying,WANG Lei,CAO Xiaolong.Calculation of circulating current in sheaths of two-circuit arranged cables and analyses of influencing factors[J].High Voltage Engineering,2007,33(4):143-146.
[19]贾欣,喻明,王瑛,等.三回路单芯电缆护套感应电势的计算[J].高电压技术,2000,26(5):61-62.JIA Xin,YU Ming,WANG Yin,et al.Calculation of induced voltage on single-core power cable metal sheath in tri-circuits[J].High Voltage Engineering,2000,26(5):61-62.
[20]陈根,唐焱,王新桥.基于ATP的高压电缆金属护套多点接地故障仿真[J].高压电器,2014(4):49-53.CHEN Gen,TANG Yan,WANG Xinqiao.Simulation of multipoint grounding faults in metal sheath of high-voltage cable based on ATP[J].High Voltage Apparatus,2014,50(4):49-53.
[2]KONG X P,WANG Y X,ZHANG Z,et al.Calculation of induced voltage in metal shield of single-core cable operated in parallel[C]∥International Conference on Power System Technology,IEEE,2010:1-8.
[3]樊友兵,赵健康,钱康,等.单芯电力电缆同相多根并联运行方式分析与优化[J].高电压技术,2010,36(10):2607-2612.FAN Youbing,ZHAO Jiankang,QIAN Kang,et al.Analysis and optimation for operation of the single-core power cables in parallel[J].High Voltage Engineering,2010,36(10):2607-2612.
[4]成健,胡力广,罗智奕,等.高压单芯电缆同相双回输电方式与运维分析[J].广东电力,2017,30(3):116-121.CHENG Jian,HU Liguang,LUO Zhiyi,et al.Same-phase and double-circuit transmission mode of high-voltage single-core cables and its operation and maintenance[J].Guangdong Electric Power,2017,30(3):116-121.
[5]郑志豪,张煌,李茂,等.输电电缆外护层绝缘电阻偏低相关因素分析及建议[J].广东电力,2017,30(11):109-113.ZHENG Zhihao,ZHANG Huang,LI Mao,et al.Analysis on relevant factors for low insulating resistance of outer sheath of transmission cable and corresponding suggestions[J].Guangdong Electric Power,2017,30(11):109-113.
[6]叶冠豪,郭湘奇,王一磊,等.XLPE电缆交叉互联系统接地直流电流在线监测[J].电力工程技术,2016,35(3):39-41.YE Guanhao,GUO Xiangqi,WANG Yilei,et al.On-line monitoring of ground DC current for cross-linking XLPE cable system[J].Electric Power Engineering Technology,2016,35(3):39-41.
[7]徐欣,陈彦.单芯高压电力电缆金属护套感应电流的研究之一-感应电流的计算和预控[J].电线电缆,2010(5):42-46.XU Xin,CHEN Yan.Investigation of the induced current in the metallic sheath of single core HV power cables,part I[J].E-lectric Wire&Cable,2010(5):42-46.
[8]陈小林,成永红,王贤清,等.XLPE电缆地线电流分析与接地改造措施一例[J].高电压技术,2006,32(2):87-88.CHEN Xiaolin,CHENG Yonghong,WANG Xianqing,et al.A-nalysis of current flowing in the ground wire of XLPE cable and modification of grounding mode[J].High Voltage Engineering,2006,32(2):87-88.
[9]XING H Y,FU Dabing,HE Runhua.Research on eliminating of ground current in power cable fault location[J].International Electronic Elements,2008.
[10]CHEN J T.Calculation method of grounding capacitive current for MV cable system[J].Electric Power Survey&Design,2015.
[11]肖少非,顾在峰.浅谈高压交联电缆的选型[J].江苏电机工程,2009,28(2):50-52.XIAO Shaofei,GU Zaifeng.Discussion on the selection of high voltage XLPE cables[J].Jiangsu Electric Engineering,2009,28(2):50-52.
[12]YANG J,YI Z,PAN Y,et al.Research on the sheath grounding current in High-speed railway feeder cable[C]∥Lightning Protection,IEEE,2014:655-658.
[13]蔡成良.浅谈湖北电网高压电缆金属护套环流问题[J].湖北电力,2010,34(4):21-22.CAI Chengliang.Discussion on circulating current in sheath of high voltage power cable in Hubei Grid[J].Hubei Electric Power,2010,34(4):21-22.
[14]张畅生,刘龙春,陈隽.110 k V海底电缆接地方式对载流量和环流的影响[J].广东电力,2017,30(8):122-127.ZHANG Changsheng,LIU Longchun,CHEN Juan.Influence of grounding mode of 110 k V submarine cable on carrying capacity and circulation[J].Guangdong Electric Power,2017,30(8):122-127.
[15]牛海清,王晓兵,蚁泽沛,等.110 k V单芯电缆金属护套环流计算与试验研究[J].高电压技术,2005,31(8):15-17.NIU Haiqing,WANG Xiaobing,YI Zepei,et al.Study on circulating current of 110 k V single-core cable[J].High Voltage Engineering,2005,31(8):15-17.
[16]杜伯学,李忠磊,张锴,等.220 k V交联聚乙烯电力电缆接地电流的计算与应用[J].高电压技术,2013,39(5):1034-1039.DU Boxue,LI Zhonglei,ZHANG Kai,et al.Calculation and application of 220 k V crosslinked polyethylene power cable grounding current[J].High Voltage Engineering,2013,39(5):1034-1039.
[17]ZHENG Jiankang,SU Xiaoting,ZHENG Linzi,et al.Research and analysis of multi-loop high-voltage cable metallic sheath current circulation calculation[J].Power Electronics,2017.
[18]刘英,王磊,曹晓珑.双回路电缆护套环流计算及影响因素分析[J].高电压技术,2007,33(4):143-146.LIU Ying,WANG Lei,CAO Xiaolong.Calculation of circulating current in sheaths of two-circuit arranged cables and analyses of influencing factors[J].High Voltage Engineering,2007,33(4):143-146.
[19]贾欣,喻明,王瑛,等.三回路单芯电缆护套感应电势的计算[J].高电压技术,2000,26(5):61-62.JIA Xin,YU Ming,WANG Yin,et al.Calculation of induced voltage on single-core power cable metal sheath in tri-circuits[J].High Voltage Engineering,2000,26(5):61-62.
[20]陈根,唐焱,王新桥.基于ATP的高压电缆金属护套多点接地故障仿真[J].高压电器,2014(4):49-53.CHEN Gen,TANG Yan,WANG Xinqiao.Simulation of multipoint grounding faults in metal sheath of high-voltage cable based on ATP[J].High Voltage Apparatus,2014,50(4):49-53.