DEMETER was a low altitude satellite in operation between 2004 and 2010 in a circular polar orbit. One of its main scientific objectives was to study ionospheric perturbations related to man-made activity. This paper investigates electromagnetic emissions triggered by Power Line Harmonic Radiation (PLHR), the man-made waves emitted at harmonics of 50 or 60 Hz. They look like rising tones or hooks with a starting frequency associated to a parent line with the frequency equal to a multiple of 50 or 60 Hz. They occur preferentially during day time in a frequency band between 1 and 4 kHz. It is shown that these emissions are rather frequent at high latitudes (3 < L <6) above industrialized areas during periods of moderate magnetic activity. Their average intensity is of the order of 10 μV2 · m-2 Hz−1. PLHR propagates in the magnetosphere and triggers emissions due to wave-particle interactions in the equatorial region.