Study On Insulation Coordination Of Line Metal-oxide Surge Arresters With Fixed Gap In Transmission Lines

With the increasing requirement on the reliability of transmission lines, the line arresters will get a wider range of applications in china, especially in the regions where the lightning is exceedingly active or the grounding resistances of towers are difficult to reduce due to the high soil resistivity.According to the design of the series gap, two different series gap structures are available: surge arrester with fixed gap and surge arrester with separated gap. The first is widely used in Japan and the other is adopted in China. As the surge arrester with separated gap has been running for several decades in Japan, the study is already very full. However, Study on the surge arrester with fixed gap is very small. In this paper, research on insulation coordination of the surge arrester with fixed gap for 110 k V transmission line has been conducted. The results and conclusion are followed:The measuring platform is constructed to get the waveforms of the surge arrester and the gap. What's more, the equivalent circuit model of the surge arrester with fixed gap is carried out and the relationship between the height of the surge arrester, the length and radius of the gap was analyzed.The lightning impulse 50% discharge voltage of experiments and volt-second characteristics of the surge arrester with fixed gap under different distance were carried out. Experience formulas of the surge arrester were discussed in accordance with the surge arrester with fixed gap. Furthermore, the author studies the characteristics of the arresters with fixed gap, the discharge characteristics of gap and the arresters with series gap to find the relationship between them by proportioning component test. The conclusion provides reference to determine parameters of the surge arrester with fixed gap.A new method is put forward about the insulation coordination: The simulation model of the transmission line was built to get the waveform of the surge arrester; afterwards, the impulse voltage generator was remolded to generate the non-standard lightning impulse(LDLI) voltage(0.5/11.2s). Finally, comparison of the insulation coordination between the standard and non-standard lightning impulse was made.