17家小型供变电场所电磁辐射测定与特征分析

Measurement and characteristics analysis of electromagnetic radiation in 17 small power supply and transformation sites

目的分析四川省17家小型供变电场所电磁辐射强度分布特征与类型特点,为小型供变电场所电磁辐射危害识别与防控提供依据。方法 2017年10—11月采用NBM550电磁辐射分析仪对17家供变电场所的工频电场和超高频辐射进行测定,分析各供变电场所电磁辐射强度分布特征与类型特点。结果 17家小型供变电场所电磁辐射测定点共计328个,工频电场测定点中平均强度为28.112 V/m,强度范围为0.350~4 698.667 V/m,各测定点均未超标。39个测定点(11.9%)电场强度超过1 000V/m,主要分布在变电区(12个点,占30.8%)与出线场升压区(27个点,占69.2%);328个超高频辐射测定点中,平均功率密度为0.000 1 mW/cm^(2),功率密度范围为<0.000 1~26.093 3 mW/cm^(2),7个测定点功率密度超过职业接触限值(0.1 mW/cm^(2)),超标率为2.13%,超标点主要位于变电站出线场。110和35 kV不同电压等级电磁辐射强度的非参数检验分析结果显示,供变电场所中出线场、发电机组和中控室的工频电场强度差异均有统计学意义(均P<0.05),其中110 kV出线场的工频电场强度>35 kV,发电机组和中控室的工频电场强度<35 kV。结论小型供变电场所电磁辐射类型存在工频电磁场与超高频辐射2种。工频电场强度较低,略高强度点主要分布在变电区和出线场升压区,而超高频辐射存在超标现象,超标区域位于变电站出线场。小型供变电场所的职业危害识别与危害防控应同时考虑工频电磁场与超高频辐射,且防护策略应根据电压等级类型和关键控制区进行制定。

Objective To analyze the characteristics and types of electromagnetic radiation intensity distribution in 17 small power supply and transformation sites in Sichuan Province,provide a basis for the identification and prevention of electromagnetic radiation hazards in small power supply and transformation sites. Methods From October to November 2017,NBM550 electromagnetic radiation analyzer was used to measure the power frequency electric field and ultra-high frequency radiation in17 small power supply and transformation sites. The characteristics and types of electromagnetic radiation intensity distribution in various power supply and transformation sites were analyzed. Results There were a total of 328 electromagnetic radiation measurement points in 17 small power supply and transformation sites.The average intensity of power frequency electric field measurement points was 28.112 V/m,with the range of 0.350-4 698.667 V/m,which all met the standard. The electric field intensity of 39(11.9%) measurement points exceeded 1 000 V/m,which mainly distributed in the substation area(12 points,30.8%)and the output field boosting area(27 points,69.2%).In 328 ultra-high frequency radiation measurement points,the average power density was 0.000 1 mW/cm^(2),the power density range was <0.000 1-26.093 3 mW/cm^(2),the power density in seven measurement points exceeded the occupational exposure limit(0.1 mW/cm^(2)),with the over-standard rate of 2.13%,and the over-standard points were mainly located in the outlet field of the substation. The non-parametric test and analysis results of the electromagnetic radiation intensities of different voltage levels of 110 kV and 35 kV showed that there was statistically significant difference in power frequency electric field strengths among the outlet field,generator set and central control room in the power supply substation,while the the power frequency electric field strength of the 110 kV outlet field was higher than that of the 35 kV,and the the power frequency electric field strengths of the 110 kV generator set and the central control room were lower than those of the 35 kV. Conclusion There are two types of electromagnetic radiation in small power supply and transformation sites:power frequency electromagnetic field and ultra-high frequency radiation. The power frequency electric field strength is low,and the points with the higher strength are mainly located in the substation area and the output field boosting area,while some of the ultrahigh frequency radiation strength exceeds the occupational exposure limit,and the over-standard points are mainly located in the outlet field of the substation. The occupational hazard identification and hazard prevention and control of small power supply and transformation sites should consider both power frequency electromagnetic fields and ultra-high frequency radiation,and the protection strategy should be formulated according to the type of voltage level and key control area.