Measurement and Analysis of Shielding Effectiveness for Power Frequency Electromagnetic Field in HV Substation

With the development of ultra-high-voltage(UHV) power grid in China,people have paid more and more attention to electromagnetic pollution in transformer substations caused by power equipments.Therefore,evaluation of electromagnetic field of power equipments becomes increasingly important.According to the national standard,measurement of electromagnetic environment in a 500 kV transformer substation was conducted,and the shielding effectiveness was computed based on the measured data.Results indicate that the current shielding uniform can almost completely shield the electric field,however the uniform has weak shielding effectiveness against magnetic field.The shielding effectiveness(SE) against electric field is 39.4 dB and 12 dB respectively at head and chest of the model,and the SE against magnetic field is 0.09 dB and 0.15 dB respectively,which indicate that the design of UHV shielding uniform should consider shielding power frequency magnetic field.