Coil FS Black Spots - Feasibility Study: Investigation of "black spots" on air inductors for high DC voltages (HVDC)

In the transmission of electric energy by means of DC voltage (HVDC) air choke coils are used for power smoothing. On the surface of these coils and impurities unacceptable perforations of the winding surface can after some time of operation is often the appearance of, referred to in the technical literature as the so-called "black spots", can be observed. Therefore, negative effects on the lifetime of the coil can not be excluded. The cause of this phenomena is believed in the electrical properties of the insulating materials used or associated with electrical charges which accumulate on the surface of the coil, in connection. The aim of this feasibility study is to develop a suitable test set to simulate these "black spots" in order to analyze their origin can cause scientifically. In particular, studies of the electrostatic behavior of test coils to be produced to be carried out.