硅脂对交联聚乙烯绝缘与硅橡胶界面电场的影响

在交联聚乙烯绝缘与硅橡胶界面涂抹硅脂是制作电缆中间接头的一个关键步骤,但实际制作电缆接头时,由于现场施工人员对硅脂认识不足,常有硅脂漏涂、涂抹不均匀的情况,而硅脂对界面电场的影响研究尚未见报道,为此建立10 kV电缆中间接头三维有限元模型,分析硅脂有、无;涂抹均匀和不均匀时的电场分布规律,同时还研究了硅脂对杂质缺陷电场的抑制作用。仿真结果表明,未涂抹硅脂时,界面最大场强比涂抹硅脂时增大了3.79倍;硅脂涂抹不均匀时,涂抹不均匀处最大场强比均匀涂抹硅脂时增加2.8倍。未涂抹硅脂、硅脂涂抹不均匀均会造成界面电场严重畸变。且硅脂涂抹不均匀时,空气隙处场强与其到外半导切断处轴向距离及空气隙厚度均成反比关系。此外界面存在杂质缺陷时,涂抹硅脂情况下电场强度远小于未涂抹硅脂时电场强度。说明涂抹硅脂对杂质缺陷的电场有很好的优化作用。规范涂抹硅脂是施工不可缺少的环节。

Effect on Electric Field of Silicone Grease on XLPE/Silicone Rubber Interface

The application of silicone grease at the interface of XLPE/silicone rubber is a key step in the production of cable intermediate joints. However, staff members are not sufficiently aware of the importance of application of silicone grease. It's often to find silicone grease not applied or unevenly smeared. The effect of silicone grease on the interface electric field has not been reported. Therefore, this paper established a three-dimensional finite element model of the 10 kV cable intermediate joint to analyze the electric field distribution under three working situations, that silicon grease is applied or not;silicon grease is distributed evenly and unevenly;and the focus on the inhibitory effect of silicone grease on other defects. The simulation results show that, when no grease is applied, the maximum field strength of the interface is 3.79 times larger than that of when silicon grease is applied, the maximum field strength under the situation that silicon grease is distributed unevenly is 2.8 times larger than that of when the silicon grease is unevenly applied. Absence of silicone grease and unevenly distributed silicon smearing both cause serious distortion of the interface electric field distribution. In addition, when there is a main insulation impurity in the silicone grease, the electric field strength of the coated silicone grease is much lower than that of the uncoated silicone grease. It shows that the application of silicone grease has optimizing function on electric field distribution under impurity defects situation. Applying silicone grease is an indispensable part of on construction.