Methods and apparatus for detecting and locating corona discharge in high-voltage, fluid-filled electrical inductive apparatus

Claim 3

The method of claim 1 including the step of providing overlays for the oscilloscope means corresponding to the electrical apparatus, with the centers of each of the beams being positioned on the overlays to correspond to the position of its associated transducer relative to the electrical apparatus.

Claim 4

The method of claim 1 wherein first and second cathode-ray oscilloscopes are provided, each having first and second beams, and first, second nd third transducers are provided, with the third transducer controlling a beam of each of the first and second cathode-ray oscilloscopes, and the first and second transducers controlling the remaining beams of the first and second cathode-ray oscilloscopes, respectively.

Claim 5

Apparatus for detecting and locating the source of a corona discharge in electrical apparatus having a casing containing electrical windings disposed in a fluid, comprising: cathode-ray oscilloscope means having at least first and second beams, and first and second deflection terminals for controlling each of the beams, first and second ramp voltage means for providing first and second triggered ramp voltages, respectively, means providing signal substantially simultaneously with the occurrence of a corona discharge in the electrical apparatus, connected to said first and second ramp voltage means, with said signal triggering the first and second ramp voltages, respectively, at least first and second mechanical to electrical transducers adapted to be disposed in vibration responsive association with the electrical apparatus, connected to said first and second ramp voltage means, respectively, said first and second transducers terminating the increase of said first and second ramp voltages, respectively when each detects the corona discharge, first and second oscillator means connected to said first and second ramp voltage means, respectively, providing first and second alternating-current sine wave output voltages having an amplitude which increases in response to the increasing magnitudes of the first and second ramp voltages, respectively, first and second phase shift means, means connecting the first alternating-current output voltage to the first terminal of the first beam, and through said first phase shift means to the second terminal of the first beam, and means connecting the second alternating-current output voltage to the first terminal of the second beam, and through said second phase shift means to the second terminal of the second beam, said first and second alternating current voltages providing first and second circles on said cathode-ray oscilloscope means, whose radii are responsive to the distances from the source of corona to said first and second transducers, respectively.

Claim 6

Apparatus for detecting and locating the source of a corona discharge in electrical apparatus having a casing containing electrical windings disposed in a fluid, comprising: cathode-ray oscilloscope means having at least first and second beams, and first and second deflection terminals for controlling each of the beams, first and second ramp voltage means for providing first and second triggered ramp voltages, respectively, means providing signal substantially simultaneously with the occurrence of a corona discharge in the electrical apparatus, connected to said first and second ramp voltage means, with said signal triggering the first and second ramp voltages, respectively, at least first and second mechanical to electrical transducers adapted to be disposed in vibration responsive association with the electrical apparatus, connected to said first and second ramp voltage means, respectively, said first and second transducers terminating the increase of said first and second ramp voltages, respectively when each detects the corona discharge, first and second oscillator means connected to said first and second ramp voltage means, respectively, providing first and second alternating-current sine wave output voltages having an amplitude which increases in response to the increasing magnitudes of the first and second ramp voltages, respectively, first and second phase shift means, means connecting the first alternating-current output voltage to the first terminal of the first beam, and through said first phase shift means to the second terminal of the first beam, and means connecting the second alternating-current output voltage to the first terminal of the second beam, and through said second phase shift means to the second terminal of the second beam, said first and second alternating current voltages providing first and second circles on said cathode-ray oscilloscope means, whose radii are responsive to the distances from the source of corona to said first and second transducers, respectively.

Claim 7

The apparatus of claim 4 including an overlay having an outline configuration of the electrical apparatus, said overlay being disposed on the cathode-ray oscilloscope means with the centers of the first and second circles being disposed on the overlay corresponding to the positions of their associated transducers relative to the electrical apparatus.

Claim 8

The apparatus of claim 4 wherein the cathode-ray oscilloscope means includes first and second cathode-ray oscilloscopes each having first and second beams, and first and second deflection terminals associated with each beam, and including a third mechanical to electrical transducer adapted to be disposed in vibration responsive association with the electrical apparatus, third ramp voltage means providing a third ramp voltage, third oscillator means providing a third alternating current output voltage, and third phase shift means, the first and second alternating-current output voltages being connected to terminals associated with beams of said first and second cathode-ray oscilloscopes, respectively, said third ramp voltage means being connected to the means which provides the signal substantially simultaneously with the occurrence of the corona discharge, to the third transducer, and to the third oscillator means, providing a third alternating-current output voltage responsive to the third ramp voltage, means connecting said third alternating-current output voltage to the first terminal of the remaining beams of each of said first and second cathode-ray oscilloscopes, and through said third phase shift means to the second terminal of the remaining beams of each of said first and second cathode-ray oscilloscopes.

Claim 9

The apparatus of claim 4 including first and second overlays for said first and second cathode ray oscilloscopes, respectively, having the configuration of first and second adjacent sidewall portions of the electrical apparatus, respectively, with each cathode-ray oscilloscope having first and second circles, the centers of which are disposed on the first and second overlays to correspond to the positions of the first and third, and third and second transducers, respectively, relative to the electrical apparatus.

Claim 12

The method of claim 8 wherein the step of providing signals r1, r2, r3 and r0 includes the steps of initiating first, second, third and fourth ramp voltages substantially simultaneously with the occurrence of the corona discharge, terminating the increase in the first, second, third and fourth ramp voltages when the first, second, third and fourth transducers detect the corona discharge, respectively, and measuring the maximum magnitude of the first, second, third and fourth ramp voltages.

Claim 13

Apparatus for locating the source of a corona discharge, comprising: electrical apparatus having a casing containing electrical windings disposed in a fluid, first, second, third and fourth mechanical to electrical transducers disposed in vibration responsive association with said electrical apparatus, with the distances from the fourth to the first, second, and third transducers being d1, d2 and d3, respectively, and with the transducers being arranged such that a line drawn from the fourth transducer to any of the other transducers is perpendicular to lines drawn from the fourth transducer to each of the remaining transducers, corona detecting means providing a signal substantially simultaneously with the occurrence of a corona discharge in the electrical apparatus, first, second, third and fourth triggered means connected to said first, second, third and fourth transducers, respectively, and to said corona detecting means, providing signals r1, r2, r3 and ro, respectively, having magnitudes responsive to the distances from the first, second, third and fourth transducers to the source of corona discharge, first, second, third and fourth squaring amplifiers connected to said first, second, third and fourth triggered signal means, respectively, providing signals r12, r22, r32 and ro2, respectively, first, second, and third summing amplifiers having gains of d1/2, d212, and d3/2 respectively, connected to said first, second and third squaring amplifiers, respectively, and to said fourth squaring amplifier, providing signals respectively, first, second and third signal means providing signals having amplitudes proportional to d12, d2/2, and d3/2, respectively, fourth, fifth and sixth summing amplifiers connected to said first, second and third signals means, respectively, and to said first, second and third summing amplifiers, respectively, providing first, second and third signals having a magnitude proportional to which signals are the Cartesian coordinates of the source of the corona discharge.

Claim 14

Apparatus for locating the source of a corona discharge, comprising: electrical apparatus having a casing containing electrical windings disposed in a fluid, first, second, third and fourth mechanical to electrical transducers disposed in vibration responsive association with said electrical apparatus, with the distances from the fourth to the first, second, and third transducers being d1, d2 and d3, respectively, and with the transducers being arranged such that a line drawn from the fourth transducer to any of the other transducers is perpendicular to lines drawn from the fourth transducer to each of the remaining transducers, corona detecting means providing a signal substantially simultaneously with the occurrence of a corona discharge in the electrical apparatus, first, second, third and fourth triggered means connected to said first, second, third and fourth transducers, respectively, and to said corona detecting means, providing signals r1, r2, r3 and ro, respectively, having magnitudes responsive to the distances from the first, second, third and fourth transducers to the source of corona discharge, first, second, third and fourth squaring amplifiers connected to said first, second, third and fourth triggered signal means, respectively, providing signals r12, r22, r32 and ro2, respectively, first, second, and third summing amplifiers having gains of d1/2, d212, and d3/2 respectively, connected to said first, second and third squaring amplifiers, respectively, and to said fourth squaring amplifier, providing signals respectively, first, second and third signal means providing signals having amplitudes proportional to d12, d2/2, and d3/2, respectively, fourth, fifth and sixth summing amplifiers connected to said first, second and third signals means, respectively, and to said first, second and third summing amplifiers, respectively, providing first, second and third signals having a magnitude proportional to which signals are the Cartesian coordinates of the source of the corona discharge.

Claim 15

The apparatus of claim 10 wherein the fourth, fifth and sixth amplifiers each have a gain of one.

Claim 16

The apparatus of claim 10 wherein the fiRst, second, third and fourth signal means each include a flip-flop circuit and an integrating circuit, with the signals r1, r2, r3 and r0 being initiated by the corona detecting means when it detects a corona discharge, and with the maximum magnitude being responsive to the time delay before its associated transducer detects the corona discharge.