Sound Analysis and PD Measurement of HV Transmission Lines

Due to the high electric fields at the surface of conductors of high voltage transmission lines effects appear, which will be called corona discharges. In the context of a research work at the University of Technology in Graz the electrical and acoustic emissions of dry and moistened high voltage transmission line conductors have been examined and evaluated in an improved way.
Instead of usual acoustic octave and one-third octave analyses the acoustic spectrum of dry and wet conductors have been evaluated with a narrowband analysis method. With this method it can be shown that the in radiated spectrum beside of the broadband noise a whole numbered multiple of the basic frequency of the applied electric field exists.