铜与铜包铝接地线缆短路熔断特性理论计算与试验
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摘要
为研究用于高压电力系统的临时接地装置抗突然短路能力及短路火灾限制措施,通过铜导体Onderdonk公式的推广算法,得到铜包铝接地线缆熔断电流的理论计算方法,以6 300 kVA大容量变压器为电流源模拟实际工作中挂接地线时可能出现的短路熔断情况,对常用的铜材料接地线缆及轻质铜包铝材料接地线缆在10 kA以上短时大电流下的熔断过程进行了试验。结果表明:绝热过程下接地线缆熔断电流的理论计算结果偏严格,通过计算公式选取接地线缆截面积具有一定的安全裕度;理论等效截面下铜包铝线缆相比铜线缆更不容易发生熔断,12. 9 kA、16. 3 kA、21. 7 kA短路电流下60 mm~2铜层体积比为10%的铜包铝裸导线熔断时间比35 mm~2铜线分别增加32. 0%、30. 1%、24. 3%;外加阻燃护层可以增加铜线缆的熔断时间而对铜包铝线缆熔断时间的影响不明显,但外加护层可以显著减少铜包铝线缆迸溅熔珠的数量,降低熔珠的引燃能力,从而对短路火灾进行有效抑制。
The present paper is inclined to study the short-circuit resistant capability and fire-preventing measures of the temporary earthing device for the high-voltage power transmission systems from two aspects,i. e. the theoretical calculation and the simulation experiment. For this purpose,we would like to propose the generalized algorithm for the aluminum conductors on the basis of the Onderdonk's equation adaptable merely for the copper conductors so as to achieve the theoretical calculation formula of the fusing current for the copper-clad aluminum( CCA) cables. To be exact,for the CCA cable with a copper volume ratio of 10%( CCA-10),we have worked out the relationship among the fusing current I_m( kA),the cross-sectional area S_(CCA-10)( mm~2) and the fusing time t( s),as shown in the following equation: I_m=165. 8 SCCA-10/t~(1/2),whereas the 35 mm~2 copper cable and 60 mm~2 CCA-10 cable can likely enjoy the same flow capacity according to the formula. Therefore,the fusing feature tests have been done with the above-mentioned 35 mm~2 copper cable and 60 mm~2 CCA cable. We can also simulate the above tests for the shortcircuit fusing situation that may occur when the earthing cable is installed in the actual site with a 6 300 kV A large-capacity transformer as the power source. On the other hand, the fusing process can be recorded with a high-speed camera while the fusing time can be measured under different RMS of a testing current at least over 10 kA. The results of the above experiments have thus proven that the theoretical results of the fusing current in the adiabatic process tend to be conservative,while the cross section may still leave a certain safety margin as a result of the formula calculation. Besides,the copper cable is prone to be fused than CCA cable under the theoretical equivalent section. In addition,at the impact of the different short-circuit currents of12. 9 kA,16. 3 kA and 21. 7 kA,the fusing time of 60 mm~2 bare CCA-10 wire can be worked out at about 32. 0%,30. 1% and24. 3%,which are longer respectively than that with the 35 mm~2 copper wire. What is more,it is also possible to increase the fusing time of copper cable to add the flame-retardant sheath,which has no obvious influence on the CCA cable. Nevertheless,once the sheath is applied,it would be possible to reduce significantly the number of CCA splash beads,which can produce a nice protective effect against the short-circuit fires.
The present paper is inclined to study the short-circuit resistant capability and fire-preventing measures of the temporary earthing device for the high-voltage power transmission systems from two aspects,i. e. the theoretical calculation and the simulation experiment. For this purpose,we would like to propose the generalized algorithm for the aluminum conductors on the basis of the Onderdonk's equation adaptable merely for the copper conductors so as to achieve the theoretical calculation formula of the fusing current for the copper-clad aluminum( CCA) cables. To be exact,for the CCA cable with a copper volume ratio of 10%( CCA-10),we have worked out the relationship among the fusing current I_m( kA),the cross-sectional area S_(CCA-10)( mm~2) and the fusing time t( s),as shown in the following equation: I_m=165. 8 SCCA-10/t~(1/2),whereas the 35 mm~2 copper cable and 60 mm~2 CCA-10 cable can likely enjoy the same flow capacity according to the formula. Therefore,the fusing feature tests have been done with the above-mentioned 35 mm~2 copper cable and 60 mm~2 CCA cable. We can also simulate the above tests for the shortcircuit fusing situation that may occur when the earthing cable is installed in the actual site with a 6 300 kV A large-capacity transformer as the power source. On the other hand, the fusing process can be recorded with a high-speed camera while the fusing time can be measured under different RMS of a testing current at least over 10 kA. The results of the above experiments have thus proven that the theoretical results of the fusing current in the adiabatic process tend to be conservative,while the cross section may still leave a certain safety margin as a result of the formula calculation. Besides,the copper cable is prone to be fused than CCA cable under the theoretical equivalent section. In addition,at the impact of the different short-circuit currents of12. 9 kA,16. 3 kA and 21. 7 kA,the fusing time of 60 mm~2 bare CCA-10 wire can be worked out at about 32. 0%,30. 1% and24. 3%,which are longer respectively than that with the 35 mm~2 copper wire. What is more,it is also possible to increase the fusing time of copper cable to add the flame-retardant sheath,which has no obvious influence on the CCA cable. Nevertheless,once the sheath is applied,it would be possible to reduce significantly the number of CCA splash beads,which can produce a nice protective effect against the short-circuit fires.
引文
[1] LI Jinxiong(李金雄). Application of earthing and shortcircuiting devices(携带型短路接地线应用技术)[M].Beijing:China Electric Power Press,2008.
[2] DAI Keming(戴克铭). Correct use of portable earthing and short-circuiting wires[J]. Electric Safety Technology(电力安全技术),2011,13(11):20-24.
[3] ZHAO Zhijun(赵志军). Earthing and short-circuiting wires-the survive lines in electrical maintenance[J]. Heilongjiang Science and Technology Information(黑龙江科技信息),2008(14):30.
[4] LI Jinxiong(李金雄),LI Yincui(李茵翠). Be safety,anti-shock:case detailed earthing wire use(讲安全防触电:案例详解接地线使用)[M]. Beijing:China Electric Power Press,2013.
[5] WANG Changyou(王昌幼). Causes and preventive measures of “inductive electricity” in maintenance of transmission lines[J]. Electric Safety Technology(电力安全技术),2010,12(9):6-12.
[6] ASTM F855—2015 Standard specifications for temporary protective grounds to be used on de-energized electric power lines and equipment[S].
[7] DL/T 879—2004 Portable equipment for earthing and short-circuiting for live working(便携式接地和接地短路装置)[S].
[8] IEC 61230:2008 Live working—portable equipment for earthing and short-circuiting[S].
[9] ZHANG Jianyu(张建宇),YAO Jinjin(姚金金),ZENG Xiangyong(曾祥勇),et al. Research progress of copper cladding aluminium composites[J]. The Chinese Journal of Nonferrous Metals(中国有色金属学报),2014,24(5):1275-1284.
[10] ZHENG Chuantao(郑传涛),DAI Yakang(戴雅康).The characteristics of copper clad aluminium wire effect on the service performance of copper clad aluminium cable[J]. Electric Wire&Cable(电线电缆),2016(6):4-7.
[11] GB/T 3955—2009 Round aluminium wire for electrical purposes(电工圆铝线)[S].
[12] ZHU Zhongming(朱仲鸣). The discussion of rated short-circuit current for portable earthing and short-circuiting wires[J]. East China Electric Power(华东电力),1994(10):23-25.
[13] ONDERDONK J M. Short-time current required to melt copper conductors[J]. Electrical World,1944,121:26,98.
[14] SSD 332—89 Technical standard of portable earthing and short-circuiting wires(携带型短路接地线技术标准)[S].
[15] BABRAUSKAS V,WICHMAN I S. Fusing of wires by electrical current[C]//Proceedings of the 12th International Conference and Exhibition on Fire and Materials.Hampshire UK:Interscience Communications, 2011:769-778.
[16] CHOI C S,KIM H K,KIM D W. Analysis of dispersive characteristics and structures of copper wire melted by overcurrent[J]. IEEJ Trans, 2005, 125(12):1327-1331.
[17] WRIGHT A,NEWBERY P G. Electric fuses[M]. 3rd ed. Stevenage,UK:Institution of Electrical Engineers,2004:191-194.
[18] TANAKA T,YAMASAKI M. Modelling of fuses for melting time and fusing current analysis[C]//Proceedings of Telecommunications Energy Conference(INTLEC). New York USA:Institute of Electrical and Electronics Engineers,2004:671-675.
[19] HU Jianguo(胡建国),TIAN Gang(田罡),LI Yang(李阳). Studies on identification of melted marks of copper-clad aluminum conductor at fire from metallographic structures[J]. Fire Science and Technology(消防科学与技术),2014,33(11):1347-1350.
[20] LI Yang(李阳). Effects of the sparks spattered from the different energy short-circuit arcs on the ignitibility and microstructure of the copper-clad aluminum conductors[J]. Journal of Safety and Environment(安全与环境学报),2018,18(5):1816-1822.
[21] ZHAO Zhengshu(赵正树),DAI Yakang(戴雅康).Study of copper clad aluminium wire annealing technology[J]. Electric Wire&Cable(电线电缆),2011(6):6-8,23.
[22] LIU Shengxin(刘胜新). Practical metal materials handbook(实用金属材料手册)[M]. Beijing:Mechanical Industry Press,2011.
[23] LU Qiupeng(卢秋朋),ZHANG Qingpeng(张清鹏),QIN Runjie(秦润杰). Introduction and simulation of skin effect of transmission line[J]. Electronic Measurement Technology(电子测量技术),2015,38(6):27-30.
[24] GB/T 12666. 1—2008 Test method on a single wire or cable under fire conditions—Part 1:Vertical specimen flame(单根电线电缆燃烧试验方法———第1部分:垂直燃烧试验)[S].
[2] DAI Keming(戴克铭). Correct use of portable earthing and short-circuiting wires[J]. Electric Safety Technology(电力安全技术),2011,13(11):20-24.
[3] ZHAO Zhijun(赵志军). Earthing and short-circuiting wires-the survive lines in electrical maintenance[J]. Heilongjiang Science and Technology Information(黑龙江科技信息),2008(14):30.
[4] LI Jinxiong(李金雄),LI Yincui(李茵翠). Be safety,anti-shock:case detailed earthing wire use(讲安全防触电:案例详解接地线使用)[M]. Beijing:China Electric Power Press,2013.
[5] WANG Changyou(王昌幼). Causes and preventive measures of “inductive electricity” in maintenance of transmission lines[J]. Electric Safety Technology(电力安全技术),2010,12(9):6-12.
[6] ASTM F855—2015 Standard specifications for temporary protective grounds to be used on de-energized electric power lines and equipment[S].
[7] DL/T 879—2004 Portable equipment for earthing and short-circuiting for live working(便携式接地和接地短路装置)[S].
[8] IEC 61230:2008 Live working—portable equipment for earthing and short-circuiting[S].
[9] ZHANG Jianyu(张建宇),YAO Jinjin(姚金金),ZENG Xiangyong(曾祥勇),et al. Research progress of copper cladding aluminium composites[J]. The Chinese Journal of Nonferrous Metals(中国有色金属学报),2014,24(5):1275-1284.
[10] ZHENG Chuantao(郑传涛),DAI Yakang(戴雅康).The characteristics of copper clad aluminium wire effect on the service performance of copper clad aluminium cable[J]. Electric Wire&Cable(电线电缆),2016(6):4-7.
[11] GB/T 3955—2009 Round aluminium wire for electrical purposes(电工圆铝线)[S].
[12] ZHU Zhongming(朱仲鸣). The discussion of rated short-circuit current for portable earthing and short-circuiting wires[J]. East China Electric Power(华东电力),1994(10):23-25.
[13] ONDERDONK J M. Short-time current required to melt copper conductors[J]. Electrical World,1944,121:26,98.
[14] SSD 332—89 Technical standard of portable earthing and short-circuiting wires(携带型短路接地线技术标准)[S].
[15] BABRAUSKAS V,WICHMAN I S. Fusing of wires by electrical current[C]//Proceedings of the 12th International Conference and Exhibition on Fire and Materials.Hampshire UK:Interscience Communications, 2011:769-778.
[16] CHOI C S,KIM H K,KIM D W. Analysis of dispersive characteristics and structures of copper wire melted by overcurrent[J]. IEEJ Trans, 2005, 125(12):1327-1331.
[17] WRIGHT A,NEWBERY P G. Electric fuses[M]. 3rd ed. Stevenage,UK:Institution of Electrical Engineers,2004:191-194.
[18] TANAKA T,YAMASAKI M. Modelling of fuses for melting time and fusing current analysis[C]//Proceedings of Telecommunications Energy Conference(INTLEC). New York USA:Institute of Electrical and Electronics Engineers,2004:671-675.
[19] HU Jianguo(胡建国),TIAN Gang(田罡),LI Yang(李阳). Studies on identification of melted marks of copper-clad aluminum conductor at fire from metallographic structures[J]. Fire Science and Technology(消防科学与技术),2014,33(11):1347-1350.
[20] LI Yang(李阳). Effects of the sparks spattered from the different energy short-circuit arcs on the ignitibility and microstructure of the copper-clad aluminum conductors[J]. Journal of Safety and Environment(安全与环境学报),2018,18(5):1816-1822.
[21] ZHAO Zhengshu(赵正树),DAI Yakang(戴雅康).Study of copper clad aluminium wire annealing technology[J]. Electric Wire&Cable(电线电缆),2011(6):6-8,23.
[22] LIU Shengxin(刘胜新). Practical metal materials handbook(实用金属材料手册)[M]. Beijing:Mechanical Industry Press,2011.
[23] LU Qiupeng(卢秋朋),ZHANG Qingpeng(张清鹏),QIN Runjie(秦润杰). Introduction and simulation of skin effect of transmission line[J]. Electronic Measurement Technology(电子测量技术),2015,38(6):27-30.
[24] GB/T 12666. 1—2008 Test method on a single wire or cable under fire conditions—Part 1:Vertical specimen flame(单根电线电缆燃烧试验方法———第1部分:垂直燃烧试验)[S].