不同电压等级变电站工频电磁场暴露状况调查
Exposure to Power Frequency Electromagnetic Field in Different Voltage Substations
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摘要:
目的 探讨电网企业不同类型变电站工频电磁场及个体磁场暴露状况。 方法 选取广东某供电局3座不同电压等级变电站及办公场所,对工作环境的电磁场强度进行检测,并对典型作业人员进行个体磁场暴露水平测量。 结果 500 kV变电站区域电场强度最高,其中隔刀母线下方电场强度达到11.573 kV/m。电抗器及大电流母线排附近磁感应强度最高,例如在500 kV变电站内的35 kV电抗器附近可测得磁感应强度达到767.79μT。办公室工频电磁场强度比变电站职业环境小得多。由于500、220 kV变电站内具有较多的大电流和高磁场源设备,因此随着变电站电压等级升高,个体磁场暴露水平逐渐升高,其中, 500 kV变电站个体磁场暴露水平分别为(1.50& #177;0.01)μT和(3.90& #177;1.32)μT,而办公室人员均值水平介于(0.02& #177;0.23)~(0.11& #177;0.10)μT。 结论 电网企业不同工作环境电磁场强度差异较大, 500 kV及220 kV运行人员有接触高强度电场和高水平工频磁场的风险。 Abstract:Objective To investigate the status of individual occupational exposure to power frequency electromagnetic field (EMF) in different substations. Methods The EMF density in the workplaces of three different voltage substations and the workers' individual exposure levels of power frequency magnetic field were gauged. Results The electric field densities recorded in the proximity of the 500 kV substation were higher than the other workplaces, of which the highest recorded electric field density was located under the disconnect switch bus bar (11.573 kV/m). The magnetic flux density values near high-current bus bar and reactors were the highest (767.79 μT). The value of EMF density reduced gradually with the voltage grade, and the lowest value was located in the office areas. The individual exposure levels of power frequency magnetic field were (1.50& #177;0.01)μT and (3.90& #177;1.32)μT in the 500 kV and the 220 kV substations respectively, and ranged from (0.02& #177;0.23)μT to (0.11& #177;0.10) μT in the office areas. Conclusion Significant differences of electromagnetic field density distribution are found in various work places. Potential health risk could be expected in workers exposed to high electric field density and high magnetic field exposure levels of 500 kV or 220 kV substations.
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