不等高接闪杆保护范围计算公式的边界条件修正

On Revisions of Boundary Conditions for Formulae of Scope Protected by Lightning Rods with Unequal Height

滚球法是直接雷防护中最常用而又有效的方法,国内外现行的大部分规范标准均采用滚球法来确定接闪器保护范围.但在实际防雷工作中,按照规范给出的公式法和作图法确定两支不等高接闪杆保护范围的过程中却出现了辅助线CE线和HO′线移到两杆外侧的情形,造成保护范围确定过程异常.因此,以这两支不等高接闪杆为特定实例,通过对其出现的异常情况进行分析,结合理论研究,剖析出要使其保护范围在确定过程中保持稳定可靠、简单方便时应具备的边界条件.通过对边界条件修正后,两支不等高接闪杆保护范围在确定过程中与规范保持一致,不会出现异常情况.

Rolling sphere method is considered as the most common and effective method in the direct lightning flash protection.In most domestic and foreign codes and standards,this method is often adopted to determine the protection scope of the air-termination system.However,with this method of formula or graph of the code to calculate the protection scope of two lightning rods with unequal height will be that line CE and line HO′locate outside of the two rods,which means abnormal.Therefore,taking these two lightning rods with unequal height as a particular example,this paper gets the boundary conditions of stable,reliable,easy and convenient method to determine the proper scope through analyzing the exceptional theoretical conditions.Based on the revised boundary conditions,two lightning rods'scope of protection is consistent with the code during the whole process without any accident.