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Luo L.,Tsinghua University | Zhang F.,China Electric Power Research Institute | Ren G.,Dalian Insulator Group Corporation Ltd | Liao Y.,China Electric Power Research Institute | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2014

In recent years, electrolytic corrosion appears on the porcelain insulators of HVDC transmission lines in China. Hence, we theoretically analyzed the effectiveness of using U-shaped zinc ring to restrain iron caps' electrolytic corrosion from the aspect of electrochemistry, which was also tested by simulative tests. Furthermore, to investigate the influences of zinc ring on mechanical and electrical characteristics of insulators under thermal expansion condition, some insulators with U-shaped zinc rings were placed in 80 ℃ environment for 50 hours and then tested. The test results indicated that, at an atmospheric pressure of 102.3 kPa, environmental temperature of 80℃, and relative humidity of 50%, absorption ratio of the tested porcelain insulators was higher than 1.8 and the impulse withstand voltage of outdoor insulation ranged from 398 kV to 434 kV, which was lower than that of inner insulation, from 486 kV to 509 kV. Hence the inner and outdoor insulation levels cooperate well and meet the operation requirements. Moreover, the installation of U-shaped zinc ring can actively restrain the electrolytic corrosion of iron caps, and it is not unfavorable for the mechanical and electrical characteristics and replacing of insulators.

Bo X.-W.,Dalian Insulator Group Co. | Bian X.-M.,Tsinghua University | Wang L.-M.,Tsinghua University | Gao D.-G.,Dalian Insulator Group Co. | Ren G.-Q.,Dalian Insulator Group Co.
Gaoya Dianqi/High Voltage Apparatus | Year: 2010

In this paper, the structural parameters of grading rings for 750 kV composite insulator were optimized by means of finite element numerical simulation based on the building of 750 kV line tower-conductors-insulators three-dimensional electric field simulation models. The effects of the grading rings were analyzed. The calculation results show that grading ring can significantly improve the distribution of electric field, the greatest electric field strength on surface of the line end grading ring less than 20 kV/cm. The corona and RIV tests show the corona inception voltage and radio interference level of the fittings and corona rings can well meet the national standards or specifications. The grading rings designed can meet the requirements of 750 kV transmission line. The result provides a useful reference for the external insulation design of 750 kV transmission.

Bo X.-W.,Dalian Insulator Group Co. | Wang L.-M.,Shenzhen University | Sun B.-Q.,Shenzhen University | Chen Y.-P.,Dalian Insulator Group Co. | Chen C.-L.,Shenzhen University
Gaoya Dianqi/High Voltage Apparatus | Year: 2011

The mechanical properties of phase-to-phase composite spacer on 500 kV compact line were studied by means of computer simulation and experimental methods in this paper. The results show that the theoretical calculation results are consistent with the experimental ones. The composite spacer has a stable post-buckling performance and the composite spacers with core diameter of 30 mm, are appropriate for the 500 kV compact transmission line. Steep front impulse voltage test was carried out on composite spacer after immersing in 0.1% NaCl solution for 48 h. The results show that the electrical insulation performance of composite spacer is reliable.

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