确定工频磁场公众曝露限值的分析

Analysis on Determination of Public Exposure Limit of Power Frequency Magnetic Field

工频磁场公众曝露限值的确定是我国工频电场、磁场曝露限值国家标准制定的关键因素。为此结合各国工频磁场限值采用情况以及电磁场人体健康影响的医学评估结果,分析了我国典型输电线路以及特殊线路情况下的工程磁感应强度状况。通过世界卫生组织(WHO)"国际电磁场计划"的调查统计可以看出,采用WHO推荐的国际标准已成为国际主流趋势,中国需要引起重视;目前国内输变电线路正常运行时周围环境中的磁场水平确实不高,但并不表明可将磁场限值降低到某个任意的水平,相反还需考虑到线路运行状况、采用新的导线技术和电缆运行等因素,这些均会使工频磁场水平显著增高。

The determination of public exposure limit of power frequency magnetic field is the key factor to establish national standards on power frequency electric and magnetic fields exposure limits in our country. Combined with the power frequency magnetic field limits adopted in countries and medical assessment results for the effects of electro- magnetic field on human health, magnetic induction levels for typical transmission line and special line projects were analyzed. It could be found by the investigation and statistics in World Health Organization （WHO）＇s International Electromagnetic Fields Project that the adoption of the international standards recommended by WHO has become the international main trend and it should be paid enough attention in China. Now the magnetic field levels are indeed not high enough in the surround environment with transmission lines in normal operation in China, but it cannot predicate that arbitrary low magnetic field exposure limit is chosen. And some factors, such as operational mode of power network and the states of buried cables in operation, need to be taken into account, which will remarkably increase the power frequency magnetic field level.