Effect of humidity on transmission lines' power frequency electric field measurements

The effect of power frequency electric field to human's living condition is being paid more attention; especially the abnormally large measurement data of power frequency electric field have caused public concern in high humidity conditions. To illustrate the abnormally large measurement data is caused by humidity which changed electrical performance of measurement equipment and its support, instead of changing space electric field distribution, this paper made theoretical analysis on power frequency electric field distribution under the transmission lines, discussed various reasons for changing measurement equipment performance caused by humidity. Then the experiment is carried out.The result of experimental verification shows that the distorted electric field nearby probe is the main reason of abnormally large measurement data, and different measurement equipment's sensitivity to humidity is also distinct. Therefore, to make sure of the accuracy of measurement data, the modification coefficient to different measurement equipment is required.