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Monitoring Device for Recording Power Line Transients

IP.com Disclosure Number: IPCOM000095630D
Original Publication Date: 1964-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Dervan, JT: AUTHOR

Abstract

This apparatus monitors and photographically records transient defects occurring in a symmetrical time varying wave-shape, e.g., one on a power line. The circuitry derives a reference signal identical in shape and phase to that which normally exists on the line being monitored. The reference signal is combined with the actual line signal in a differential amplifier to give a difference signal. Any transients on the line appear at the output of the differential amplifier. The output of the differential amplifier is used to trigger an oscilloscope and a camera which photographs the actual power line wave-shape at the time of the transient.

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Monitoring Device for Recording Power Line Transients

This apparatus monitors and photographically records transient defects occurring in a symmetrical time varying wave-shape, e.g., one on a power line. The circuitry derives a reference signal identical in shape and phase to that which normally exists on the line being monitored. The reference signal is combined with the actual line signal in a differential amplifier to give a difference signal. Any transients on the line appear at the output of the differential amplifier. The output of the differential amplifier is used to trigger an oscilloscope and a camera which photographs the actual power line wave-shape at the time of the transient.

Power line signal A is applied to input 10 of pulse generator 12. Generator 12 may comprise a Schmitt trigger or any other suitable device which produces a wave-shape similar to that shown at B which is rectangular in shape and has the same period as wave-shape A. Output 14 of generator 12 feeds band-pass filter 16 which filters out only the fundamental frequency (wave-shape C) of the wave- shape B. The output 18 of filter 16 is amplified and phase shifted by amplifier and phase shifter 20 producing wave-shape D which is 180 degrees out of phase with wave-shape A. Output 22 of amplifier 20 and the input wave form 10 are combined in differential amplifier 24, the output 26 of which has the shape shown by curve E, coinciding with the defective portion of wave-shape A.

In order t...