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电磁屏蔽体对电力系统二次设备的冲击电场防护作用明显,其屏蔽效能的实验研究对保护小室、机箱等屏蔽体设计有指导意义。为此,搭建了一套基于光电电场传感器的冲击电场作用下屏蔽体屏蔽效能实验研究系统;比较了不同材料屏蔽体的屏蔽效能,研究了网格尺寸对金属网格屏蔽体屏蔽效能的影响;对比了不同频率下金属网格屏蔽体的屏蔽效能差异,研究了接地电阻对金属网屏蔽体屏蔽效能的影响。研究表明:金属材料屏蔽体的屏蔽效能较好;金属网格尺寸<10 cm的屏蔽体可获得>20 dB的屏蔽性能;操作波和雷电波作用下的屏蔽效能基本相同,前者略大于后者;减小接地电阻可有效提高金属屏蔽体的屏蔽效能。
The shielding effect of the electromagnetic shielding body on the impact electric field of the secondary equipment of the power system is obvious. The experimental research on its shielding effectiveness is of guiding significance for the design of the shielding body for protecting the cab and the chassis. For this reason, a set of experimental research system of shielding effectiveness based on photoelectric field sensor is established. The shielding effectiveness of shielding materials with different materials is compared. The influence of grid size on shielding effectiveness of metal grid shielding is studied. The differences of shielding effectiveness between metal grid shields at different frequencies are compared and the influence of grounding resistance on shielding effectiveness of metal grid shields is studied. The results show that the shielding effectiveness of the metal shield is better than that of the metal shield, the shielding performance of> 20 dB can be obtained for shields with metal grid size <10 cm, and the shield efficiency is basically the same under operating and lightning waves, ; Reduce the grounding resistance can effectively improve the shielding effectiveness of the metal shield.