雷电灾害风险评估中Am 因子的选取方法研究

雷电击中建筑物附近的有效截收面积Am是雷电灾害风险评估的基础因子之一，目前广泛应用标准IEC62305－2规定的选取方法，计算中未考虑项目所在位置的雷电环境及项目特性，计算结果缺乏针对性。中本文从雷击建筑物附近可能产生的风险出发，分析附近雷击点的危害方式及危害程度，探讨根据工程实际确定参数Am值的一般方法，得出结论：参数Am值应在分析确定可能造成危险的雷击点的最远距离的基础上定量计算，以保证计算结果的针对性、科学性。建筑物附近的雷击点以雷电电磁脉冲的形式对内部电气电子设备造成危害，危害程度与该点雷电流强度、建筑物规模及防护措施等因素有关。

Research on the Selection Method of Factor Am in the Evaluation of Lightning Disaster Risk

The collection area of flashes striking near the structure(Am)is one of the basic factors in the lightning risk assessment.The selection methods provided by standard IEC62305-2 is widely used now,but this methods does not consider the lightning environment of the project position and the project characteristics,so that the calculation result lack specificity.This paper analyses the hazard mode and extent of the lightning strikes nearby,and investigates the general method to determine the values of the parameters Am according to engineering practice from the possible risks when lightning strike buildings,and draw a conclusion: Obtaining the parameters Am should be quantitative calculated based on the analyzing the maximum distance of the lightning possibly striking the structure in order to ensure the orientation and the scientific of the calculation results. The lightning strike point near the building damage the internal electrical equipment in the form of lightning electromagnetic pulse ,the extent of the injury relate to the thunderstorm current intensity the building scale and other protective measures.