固体绝缘环网柜涂屏蔽层对复合绝缘电场的影响研究

Influence of Solid Insulation Switchgear′s Shield Layer on Composite Insulation Electric Field

为研究固体绝缘表层涂屏蔽层对其内部电场分布的影响,利用有限元分析软件对固体绝缘在有无屏蔽层两种状态下分别进行静电场仿真。仿真结果表明,屏蔽层的引入能实现相间屏蔽,但也使得固体绝缘腔体内相同结构的相同区域电场强度增加,腔体内伞裙附近空气电场强度较大,极易击穿,进而影响附近环氧树脂电老化。依据电场复合绝缘理论,提出增加腔体内部导电体距离环氧内壁的距离,采用界面绝缘消除小间隙气隙,增大导体和环氧树脂的曲率半径和倒圆角半径等降低场强的办法。对优化后的模型重新进行电场分析,伞裙附近空气电场强度由3.81kV/mm降至2.87kV/mm,验证了优化方法理论上的可行性。

To study the influence of shield layer of solid insulation switchgear on internal electric field, the finite element analysis software was used to simulate the electrostatic field of solid insulation in two states with and without shielding layer. The simulation results show that the introduction of the shield can realize phase shield, but also increased the electric field intensity in the same area of solid insulation cavity. Electric field intensity of the air near the cavity increased after coating shield layer. It can easily breakdown the air and cause ageing of epoxy resin. Increasing the distance between electrical conductor and the lining of epoxy resin cavity based on the composite insulation theory was proposed. Series of ways to reduce the field strength were adopted, for example, eliminating the small gap by adopting Interface insulation. Increasing radius and chamfering of electrical conductor and epoxy resin. The electric field of optimized model was analyzed. The electric field intensity of air near umbrella decreased from 3.81kV/mm to 2.87kV/mm. It confirmed the feasibility of optimization measure in the theory.