External partial discharges at high-voltage electrodes (corona) possess an acoustic spectrum, which extends to the ultrasonic region. Because of the strong directivity of highfrequency sound waves, ultrasonic detectors do not only allow detection, but also the localization of corona discharges, for instance, in switch yards, high-voltage test set-ups or transmission lines. The ultrasonic detector USD 38O1/38O2 operates at a frequency of approx. 33 kHz that is particularly suitable for external partial discharge detection. The combination of a highly directional ultrasonic microphone and a parabolic reflector system allows an exceptional directivity of the acoustic sensitivity. The microphone output signal is picked up by a selective amplifier and transformed into an audible signal. This allows a simple evaluation of the partial discharge intensity by headphones.
USD 3801 / 3802
|||with optical sight|