500 kV双联耐张瓷绝缘子串的串间放电现象

Discharge Phenomenon of a 500 kV Double Tension Porcelain Insulator String

以某换流站500 kV出线双联耐张瓷绝缘子串为研究对象,研究了双联瓷绝缘子串串间放电现象的成因。开展了电阻测试、剖面染色等实验,建立了双联瓷绝缘子串电场与放电仿真模型,获得了双联绝缘子串空间电场分布规律。研究结果表明:水汽侵入水泥黏合剂缝隙导致多个绝缘子阻值下降形成大量零值绝缘子(西侧20片、东侧4片)。由于两侧零值绝缘子数量差距较大,产生122 kV串间电位差是串间放电的主要成因。

The mechanism of this phenomenon was studied with a double tension porcelain insulator strings in a 500 kV converter station.Experiments including resistance testing and cross-sectional staining were conducted,and a simulation model of double insulator strings was established to obtain the distribution pattern of the space electric field.The result shows that water vapor intrusion into the cement adhesive gap resulted in the resistance decrease of several insulators and the formation of 24 zero-value insulators(20 on the west side and 4 on the east side).The 122kV voltage difference between the strings was the main cause of the inter string discharge.