电动车组车顶复合绝缘子内部间隙电场分析

发布时间：2018-12-21 17:02

【摘要】：车顶复合绝缘子芯棒和护套的界面存在气体或液体间隙时,间隙周围的电场会发生畸变。电动车组频繁的过电压会诱发局部放电,加剧内绝缘的蚀损老化。为了准确评估间隙存在对电场分布的影响,针对车顶绝缘子某次内绝缘击穿事故,基于ANSOFT MAXWELL建立了电动车组母线支持绝缘子的多参数三维有限元模型。分析了存在气体、液体间隙时绝缘子内部电场,同时研究了间隙的尺寸、位置对电场分布的影响。结果表明:绝缘子内部出现气体间隙时,电场强度最大可能提升至无气隙时的2.65倍,进而引发强烈的局部放电;液体间隙内部导电离子浓度较大,电导率达到10-5 S/m时,间隙外部承受的电场强度可能达到49.3 kV/cm;间隙越长或离高压端金具的距离越短,绝缘子内绝缘受到的破坏越重,距离小于5 mm时更为明显。
[Abstract]:When the gas or liquid gap exists in the interface between the core rod and sheath of composite insulator on the roof, the electric field around the gap will be distorted. The frequent overvoltage of EMU will induce partial discharge and aggravate the corrosion and aging of internal insulation. In order to accurately evaluate the influence of gap on electric field distribution, a multi-parameter three-dimensional finite element model of EMU busbar supported insulator was established based on ANSOFT MAXWELL for an internal insulation breakdown accident of roof insulator. The internal electric field of insulator with gas and liquid gap is analyzed, and the influence of gap size and position on electric field distribution is studied. The results show that when gas gap occurs in the insulator, the maximum electric field intensity can be increased to 2.65 times of that in the absence of air gap, and then a strong partial discharge is induced. When the conductivity reaches 10-5 S / m, the electric field intensity outside the gap may reach 49.3 kV/cm;. The longer the gap or the shorter the distance from the high-voltage end fixture, the more serious the damage to the insulator's internal insulation is, especially when the distance is less than 5 mm.
【作者单位】：西南交通大学电气工程学院;
【基金】：国家自然科学基金(51107104)~~
【分类号】：TM216

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