超高层电梯机房防雷区磁场强度分析及防御技术

Magnetic Field Intensity Analysis in Lightning Protection Zone of Elevator Machine Room for High-Rise Buildings and Defense Technology

近年来,由雷击引起的电梯停运事件时有发生,雷电对电梯的损坏主要有闪电电涌侵入、地电位反击、辐射电磁场等3种主要途径。经过专业技术人员的现场鉴定调查发现,以雷电辐射电磁场诱发的控制板损坏引起的为最多。以一幢超高层建筑物为例,计算雷击建筑物以外附近218 m和雷电直接击在建筑物上防雷区LPZ1区、LPZ2区内磁场强度,分析雷击时辐射电磁场对电梯机房LPZ2区控制设备的损坏机理,并得出以下结论:确定点距LPZ1区屏蔽最短距离取最大值能尽可能减小磁场强度值;电梯机房LPZ1区屏蔽网格宽度w≤0.15m时,若建筑物电梯机房顶接闪器遭受小于等于150kA雷电流直接雷击,机房内控制设备一般不会受到辐射电磁场的干扰。

In recent years, lightning-induced elevator accidents often occur. The damage to the elevator is caused mainly through the approaches of surge intrusion, ground potential counterattack, and electromagnetic impulses. Through the on-site identification of the professional personnel, it is found that the accidents are mostly caused by the damaged control-board resulted from the lightning induced electromagnetic effect. The magnetic field intensities, for example, are calculated for the area of 218 m around the stroked building and the LPZ1, LPZ2 in the studied area in the case of lightning directly stroked on the buildings. The analysis is made of the damage mechanisms of lightning electromagnetic pulses to control equipment in the LPZ2 area of the elevator machine room, and it is concluded that to make the distance of dw as big as possible can reduce the magnetic field intensity values; if the shielding meshes for the LPZ1 area of the elevator machine room has a width of 0.15 m or less, when the lightning