复合绝缘子芯棒界面微裂纹对场强电位分布性影响

Influence of Composite Insulator Core with Interface Micro-crack on Field Strength and Potential Distribution

因复合绝缘子芯棒的生产工艺或材料热胀冷缩效应等客观因素均可能造成芯棒界面的微裂纹存在。从场强电位分布角度出发,对存在局部芯棒微裂纹建模,并且对裂纹中充斥的不同微杂质进行仿真计算,结果表明:界面微裂纹的存在会导致金具处最大场强数值进一步增大,局部场强会发生明显畸变,并抬升了高压端前3片伞裙的电压承担值;水分渗入微裂纹内比较于酸液杂质对场强与电位分布均匀性影响更为明显;场强的畸变与电位的分布不均匀与界面微裂纹的深度有一定性的关系。场强畸变与伞裙电压承担差异会诱导放电通道的形成,进一步促进局部微裂纹的"膨胀",如此反复使裂纹内驻存更多微杂质(水分、酸液)等,使芯棒处于更恶劣的运行环境中,久之可能导致脆断的可能。

The processing technology of composite insulator core or the thermal expansion and cold contraction effect of material may cause the micro crack on the interface of composite insulator core.In this paper the existence of local micro crack is modeled and the crack filled with different micro-impurities is simulated and calculated for analyzing the field strength and potential distribution.As the results show,the existence of interface micro-cracks will lead to the maximum field strength value of the hardware;local field strength will be significantly distorted;the three sheds voltage can be raised.The effect of water infiltration on the uniformity of field strength and potential distribution is much obvious compared with that of acid infiltration.The distortion of field strength and the distribution of uniform potential have some links to the depth of the interface micro-crack.The electric field intensity distortion and the discharge voltage of the umbrella skirt will induce the formation of the discharge channel,further promote the"expansion"of the local micro-crack,so that the crack is filled with more micro-impurities(water,acid),thus the core is in a worse operating environment,and may lead to the possibility of brittle fracture.