T&D World Magazine

Cable Fault Pinpointer Features Background Noise Reduction

The new digiPHONE+ cable fault pinpointer from Megger incorporates Background Noise Reduction (BNR) technology. The pinpointer is based on the familiar and well-proven technique of comparing acoustic and electromagnetic signals that are produced by flashovers at the fault when a surge voltage is applied to the cable.

In the past, the capabilities of pinpointers have been limited by the difficulty of distinguishing between the acoustic signal produced by the fault and background noise produced by, for example, passing road traffic and nearby pedestrians. In the digiPHONE+, Megger’s BNR technology solves this problem by comparing the acoustic signals produced by two successive flashovers, and eliminating all types of noise that are not present in both signals. The result is a clean acoustic signal that relates only to the fault and, therefore, allows its location to be accurately determined.

The new instrument also features a simplified easy-to-read display that continuously shows the user their distance from the fault and the direction to it. The display positively shows when the fault location is reached and, at this point, it indicates the approximate depth of the fault below ground.

Other key benefits of Megger’s new digiPHONE+ cable fault pinpointer include a volume limiter, which ensures that the user is not exposed to sounds louder than 84 dB(A) in the instrument’s headphones, and an Automatic Proximity Mute (APM) system, which mutes the headphones when the operator’s hand approaches the instrument. This ensure that no cracks and bangs are heard when the device is moved from place to place.



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