Abstract: An apparatus for detecting a partial discharge in a high voltage transformer comprising a live tank comprises a metal box detachably connected to the tank; a first acoustic sensor inside the box for converting acoustic waves in a first frequency band to a first electrical output signal; signal conditioning circuitry inside the box for amplifying and filtering the first electrical signal; an electrical to optical converter, inside the box, for converting the amplified and filtered electrical signal to an optical signal; a fiber optic link for carrying the optical signal to a location remote from the transformer; and an optical to electrical converter at the remote location for converting the optical signal to a second electrical signal, the second electrical signal being indicative of a partial discharge inside the tank. The second electrical signal may be fed to an oscilloscope or recording equipment for determination of the occurrence of a partial discharge.

Abstract: A system which measures direct current drift and noise in sensor signals from redundant sensors utilizing a parity-space algorithm. Parity vector signals produced by the parity-space algorithm are averaged to provide a direct current (DC) drift signal. An instantaneous noise signal is found by subtracting the direct current drift signal from a parity vector signal for one of the samples of the sensor signals. The RMS value of the instantaneous noise signals are averaged to provide sensors noise signals.