不同等级变电站作业环境工频电磁场强度比较分析

目的通过对不同等级变电站作业环境工频电磁场强度比较分析,探讨其职业健康的风险。方法典型抽取110 kV和220 kV变电站各2个,500 kV变电站1个,按照DL/T 988-2005,采用德国PMM8053电磁场测量仪,EHP-50工频电磁场探头对各作业点进行布点测量。依据2010年国际非电离辐射防护委员会(ICNIRP)限值分析不同等级变电站超标情况。结果 192个被测作业点,16.15%(31个作业点)电场强度超过限值要求,磁场强度除500 kV变电站1个作业点磁场强度超过限值要求,其余测点均符合限值要求。110 kV变电站有52个作业点电场强度均符合限值要求;220 kV变电站8.3%(5个作业点)电场强度超过限值要求;550 kV变电站有32.5%(26个作业点)电场强度超过限值的要求。3组超标率有显著性差异(χ2=28.52,P<0.01),电压等级越高超标率越高,相关系数为0.38(P<0.01)。结论高压变电站工频电场广泛存在,电压等级越高健康风险越大,500 kV变电站超标情况较严重,作业人员健康风险大,需要采取相应的防控措施。

Measurement and assessment of occupational environment in different grade transformer substations

Objective To evaluate the risk of occupational health in different voltage level substations by comparing the strength of power frequency electromagnetic field （EMF） in working place. Methods Two 110 kV, two 220 kV and one 500 kV substations were typically sampled in this research. The measurement was carried out with EMF strength meters （PMM8053, Germany） and power frequency EMF detector （EHP- 50, Germany） in working sites, according to DL/T 988 - 2005. The results were assessed and analyzed according to the exposure limits of International Commission on Non - Ionizing Radiation Protection （ICNIRP） 2010 Guidelines. Results One hundred and Ninety -two sites were measured and the strength of electric field （EF） in 31 sites （16. 15% ） were beyond the limit value while the strength of magnetic field （MF） in only one site in 500kV substation was beyond the limit value;The strength of EF in 5 sites （8.3%） in 220 kV substations and 26 sites （32. 5% ） in 110 kV substations were beyond the limit value. The difference of over standard rate of three groups was statistically significant （X^2 = 28.52, P 〈 0. 01 ）. The higher voltage classes are with the higher over standard rate, and the correlation coefficient was 0. 38 （P 〈 0. 01 ）..Conclusion The exposure of power frequency EF ex- ists widely in the high voltage substations. The higher voltage classes were with the higher health risk. The over standard rate of the strength EMF in 500 kV substation is serious, therefore, it is necessary to adopt properly preventive and control measures to orotect the worker health.