Electric Power Research Institute Incorporated

Ontario Hydro

Iris Power Engineering Inc.

Howard G Sedding

Blake A Lloyd

Frank Y Chu

Steven R Campbell

Robert M Cilic

James Penman

A method and device for distinguishing between partial discharge and electrical noise in high voltage conductors such as in motor and generator stators, power cables, gas insulated switchgear and other equipment where high voltage insulation is subject to deterioration. A series of comparators sets a trigger threshold and a voltage range, set by a computer, whereby pulses falling within the voltage range are sampled at four short intervals and then four longer intervals to produce a general pulse width profile. The voltage range is varied by the computer so that a number of voltage ranges are sampled during each selected portion of an ac cycle. The pulse width of pulses falling within each voltage range is recorded by the computer, and displayed graphically. In a preferred embodiment the device is provided with two channels, for receiving a signal from each end of a partial discharge detector described in U.S. Pat. No. 4,949,001. In a preferred embodiment the method and device provide information concerning the polarity, arrival time and width of the measured pulses, which thus enables the operator to distinguish between partial discharge and noise and to detect the general location from which the pulse originated.

Method and device for distinguishing between partial discharge and

An electronic rotor temperature sensor which is encased in a plug or housing which can be removably mounted in the rotor of a generator or motor and transmit r.f. signals encoded with temperature information.

Electronic rotor temperature sensor

In order to determine the occurrence of a stator fault in an induction motor during operation of the motor, the axial leakage flux is monitored during operation of the motor. The occurrence of a stator fault is detected by observing a change in selected harmonic components of the axial leakage. The angular position of the fault with respect to a datum position is determined by noting and recording changes in the axial leakage flux at a plurality of positions distributed symmetrically around the axis of the motor and computing the angular position by triangulation. The axial leakage flux is detected by individual search coils located at said plurality of positions.

Method and apparatus for detecting stator faults in rotary

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Toronto, Canada

Howard G Sedding