Analysis on power line harmonic radiation in China space

A method was studied to detect power line harmonic radiation (PLHR) events using electromagnetic field data of DEMETER satellite and the characteristics of PLHR events in China space were discussed. All the satellite electric field strength data in China space during the 6 years between 2005 and 2010 were analyzed by time-frequency analysis and Welch spectrum estimation method, with 151 PLHR events detected. Statistical analysis and typical examples were presented. The results show that the frequencies of PLHR events in China space are distributed between 1 000 and 4 500 Hz. Most spectral lines of them are odd times of 50 Hz, with frequency spacing of 50/100 Hz. PLHR events have some closely connections with the change and development of power grid, but have no relations with geomagnetic activities, and they appear seasonal differences and differences between day and night. The possible factors that affect PLHR detecting were presented in the end.