Analysis of EM Environment inside Control Room of Lingbao HVDC Substation

When thyristor valves in Lingbao HVDC Substation run with full power,the image and characters on the CRT screen tremble seriously in the control room.In order to give the reason why the screen trembles and to find out the influence of the EM environment in the control room on the health of the staff,the paper analyses the harmonic current of the converter transformers and the valves,the result is analyzed.The location of the control room and valves is also analyzed.The low frequency magnetic field and radio frequency interference is measured in the control room.The conclusion is drawn according to the analysis and the measurement result that the low frequency magnetic fields(the power frequency magnetic field and harmonic magnetic field) causes the tremble,also the detected influence of EM environment in the control room on the health of the staff shows that it is not intolerable according to the guide of the ICNIRP.