| 摘要 |
The present invention relates to a method and a device for detecting partial discharges in cables and accessories, comprising the following steps of: interrupting the metal earth shield of the cable; connecting both sides of the interrupted sheath to a measuring instrument; arranging a connection between both sides of the interrupted sheath which is at least suitable for transferring the signals with the mains frequency; and displaying the signal, wherein only signal components with frequencies greater than 0.5 MHz are displayed. As a result of these steps, the interference associated with the first mentioned frequency range is avoided. It is noted here that the signal/noise ratio of the frequency range applied according to the invention is more favourable. In order to properly be able to examine the quality of a partial discharge, it is important to relate it to the voltage of the cable in which the partial discharge takes place. The present invention provides a method wherein prior to display the signal is combined with a signal representing the mains voltage. It is especially attractive when the signal representing the mains voltage is generated in contact-free manner, for example in capacitive manner. <IMAGE> |
