Partial discharge monitoring apparatus and partial discharge remote monitoring system for rotating electric machines
First Claim
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1. A partial discharge monitoring apparatus for a rotating electric machine, said partial discharge monitoring apparatus comprising:
- a partial discharge detecting circuit which measures each signal output from a partial discharge sensor located in the rotating electric machine simultaneously in a first frequency band and a second frequency band, wherein the first frequency band, having a bandwidth between 1 MHz and 3 MHz, is within a range of 5 MHz to 40 MHz, the second frequency band is band at least 5 MHz higher than the first frequency band, detection time for detecting each signal includes a peak hold time starting from a point of detection of a signal in the first frequency band and ending at a point of detection of a peak value of the signal, and a dead time, which occurs after the peak hold time, and a next-occurring signal is detected after the dead time has elapsed.
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Abstract
A partial discharge monitoring apparatus for a rotating electric machine includes a partial discharge detecting circuit which measures each signal output from a partial discharge sensor located in the rotating electric machine simultaneously in a first frequency band and a second frequency band. Detection time for detecting each signal includes a peak hold time and a dead time, which comes after the peak hold time. A next-occurring signal is detected after the dead time has elapsed.
20 Citations
15 Claims
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1. A partial discharge monitoring apparatus for a rotating electric machine, said partial discharge monitoring apparatus comprising:
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a partial discharge detecting circuit which measures each signal output from a partial discharge sensor located in the rotating electric machine simultaneously in a first frequency band and a second frequency band, wherein the first frequency band, having a bandwidth between 1 MHz and 3 MHz, is within a range of 5 MHz to 40 MHz, the second frequency band is band at least 5 MHz higher than the first frequency band, detection time for detecting each signal includes a peak hold time starting from a point of detection of a signal in the first frequency band and ending at a point of detection of a peak value of the signal, and a dead time, which occurs after the peak hold time, and a next-occurring signal is detected after the dead time has elapsed.
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2. A partial discharge monitoring apparatus for a rotating electric machine, said partial discharge monitoring apparatus comprising:
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a partial discharge detecting circuit including first and second frequency band detecting circuits which include first and second attenuators, first and second bandpass filters, and first and second peak hold circuits, respectively; and
a controller CPU, wherein the first and second frequency band detecting circuits simultaneously measure each signal output from a partial discharge sensor located in the rotating electric machine, the controller CPU controls measurement ranges of the first and second frequency band detecting circuits by controlling the first and second attenuators, the first and second bandpass filters allow signals which have passed through the first and second attenuators to pass if the signals fall within first and second frequency bands, respectively, the second frequency band of the second bandpass filter being higher than the first frequency band of the first bandpass filter, the first and second peak hold circuits detect a peak value of an input signal when the input signal, among the signals which have passed through the first and second bandpass filters, exceeds a signal detection level, the second peak hold circuit operating only when the first peak hold circuit has operated, detection time for detecting the signal input into each of the first and second peak hold circuits includes a peak hold time, a reset times and a dead time, and a next-occurring signal is detected after the dead time has elapsed. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9)
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10. A partial discharge remote monitoring system for a rotating electric machine, said partial discharge remote monitoring system comprising:
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a partial discharge sensor located in the rotating electric machine;
a partial discharge monitoring apparatus; and
a supervisory control center connected to the partial discharge monitoring apparatus via a communications network, wherein the partial discharge monitoring apparatus comprises;
a partial discharge detecting circuit including a comparator and first and second frequency band detecting circuits which include first and second attenuators, first and second bandpass filters, and first and second peak hold circuits, respectively; and
a controller CPU, wherein the first and second frequency band detecting circuits simultaneously measure each signal output from the partial discharge sensor located in the rotating electric machine, the controller CPU controls measurement ranges of the first and second frequency band detecting circuits by controlling the first and second attenuators, the first and second bandpass filters allow signals which have passed through the first and second attenuators to pass if the signals fall within first and second frequency bands, respectively, the second frequency band of the second bandpass filter being higher than the first frequency band of the first bandpass filter, the first and second peak hold circuits detect a peak value of an input signal when the input signal, among the signals which have passed through the first and second bandpass filters, exceeds a signal detection level, the second peak hold circuit operating only when the first peak hold circuit has operated, detection time for detecting the signal input into each of the first and second peak hold circuits includes a peak hold time, a reset time, and a dead time, a next-occurring signal is detected after the dead time has elapsed, and the comparator compares signal data on the signal detected with a preset reference value and immediately transmits the signal data to the supervisory control center if a partial discharge which has occurred in the rotating electric machine exceeds a permissible level. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification