Theoretical analysis on affecting factors of power line harmonic radiation

Power line harmonic radiation (PLHR) is an artificial electromagnetic pollution source in the near-earth space environment. Up until now, there has been little quantitative research on its formation mechanism. This paper details a model and solver for electromagnetic waves propagation in a stratified anisotropic ionosphere. In our model, these electromagnetic waves are generated by an arbitrary electric dipole source above a nonideal conductive ground. The matrix-exponent method and a full-wave method are combined to analyze the model, avoiding the problem of numerical overflow and swamping in numerical calculations. The computing results obtained from the proposed method and the observed electric field data by using DEMETER satellite are compared and found to be in good agreement. Furthermore, this paper considers the effects on PLHR propagation in the ionosphere due to dipole source frequency, earth's conductivity, electron density, geographic latitude, and geomagnetic field orientation. Results show that when the frequency increases, the strength of PLHR penetrating into the ionosphere has an increasing tendency. If the harmonic current remains constant, lower ground conductivity and electron density of the ionosphere result in higher radiation power. PLHR propagates along the direction of the geomagnetic field in the ionosphere, and its strength decreases with the increasing geomagnetic inclination at the same height. In addition, the radiation power of less than 1 W may trigger PLHR.