Systematic investigation of power line harmonic radiation in near-Earth space above China based on observed satellite data

The environmental impact of power line emission and power line harmonic radiation (PLHR) in near-Earth space has become an increasing concern. In the years 2004–2010, based on the data of microsatellite DEMETER, 133 PLHR events are detected in near-Earth space above China. PLHR has a close correlation with the development of China's electric power network. Its central frequency appears to depend on the latitude. The geographic distribution of the events occurs in clusters. Several events take place continuously above specific regions. PLHR shows no significant dependence on geomagnetic activity. There are more events in daytime than in nighttime and more in winter than in summer. The differences of naturally generated whistlers and power consumption between day and night and the strong thunderstorms in local summer may lead to such diurnal and seasonal differences of PLHR.