Apparatus for waveform disturbance monitoring for an electric power system
First Claim
1. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
- sensing means for sensing said AC waveform;
sampling means for sampling said AC waveform sensed by said sensing means;
means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform;
means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles,trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold;
capture means for capturing said digital samples of said AC waveform in response to said trigger signal; and
wherein said sensing means includes means for sensing a voltage of said AC waveform; and
wherein said means for generating a value includes means for generating a dV/dt value as said value representing a change in magnitude with respect to time of said AC waveform.
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Abstract
A monitor/analyzer for an alternating current (AC) electrical system responds to power line disturbances by generating a trigger signal when a change in voltage with respect to time electrical parameter is greater than a programmed threshold. The monitor/analyzer includes a sensor for sensing an AC waveform in the electrical system, an analog-to-digital converter for sampling the AC waveform, and a microcomputer. Firmware of the microcomputer cooperates with the A/D converter and provides a plurality of digital samples of the AC waveform for each of some of its AC cycles. The firmware generates each of plural dV/dt parameters of the AC waveform from a corresponding adjacent pair of the digital samples within one of the waveform'"'"'s AC cycles. A trigger signal is generated when one of the dV/dt parameters is greater than the programmed threshold. The digital samples of the AC waveform before and after the power line disturbance are captured and output to a display in response to the trigger signal.
117 Citations
13 Claims
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1. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
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sensing means for sensing said AC waveform; sampling means for sampling said AC waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform; means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles, trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold; capture means for capturing said digital samples of said AC waveform in response to said trigger signal; and wherein said sensing means includes means for sensing a voltage of said AC waveform; and
wherein said means for generating a value includes means for generating a dV/dt value as said value representing a change in magnitude with respect to time of said AC waveform.
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2. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
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sensing means for sensing said AC waveform; sampling means for sampling said AC waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform; means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles; trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold; capture means for capturing said digital samples of said AC waveform in response to said trigger signal; and wherein said means cooperating with said sampling means includes means for providing said digital samples with a periodic time interval between an adjacent pair of said digital samples; and
wherein said means for generating a value includes means for comparing the adjacent pair of said digital samples to determine said value representing a change in magnitude with respect to time of said AC waveform. - View Dependent Claims (3)
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4. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
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sensing means for sensing said AC waveform; sampling means for sampling said AC waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform; means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles; trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold; capture means for capturing said digital samples of said AC waveform in response to said trigger signal; wherein said digital processing means includes means for selecting one of a plurality of predetermined thresholds as said predetermined threshold; and wherein said electric power system includes at least two voltages; and
wherein said trigger means includes a first predetermined threshold for a first voltage and a second predetermined threshold for a second voltage.
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5. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
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sensing means for sensing said AC waveform; sampling means for sampling said AC waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform; means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles, trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold; capture means for capturing said digital samples of said AC waveform in response to said trigger signal; and wherein said predetermined threshold is a first predetermined threshold; and
wherein said trigger means includes means for generating a first trigger signal when said value representing a change in magnitude with respect to time of said AC waveform is about greater than the first predetermined threshold, and means for generating a second trigger signal when both of the pair of said digital samples are about less than a second predetermined threshold. - View Dependent Claims (6, 7, 8, 9)
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10. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
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sensing means for sensing said AC waveform; sampling means for sampling said AC waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform; means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles, trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold; capture means for capturing said digital samples of said AC waveform in response to said trigger signal; and wherein said trigger means includes means for generating the trigger signal when said value representing a change in magnitude with respect to time of said AC waveform is greater than or equal to the predetermined threshold.
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11. An apparatus for monitoring an electric power system including an alternating current (AC) waveform having a plurality of AC cycles, said apparatus, comprising:
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sensing means for sensing said AC waveform; sampling means for sampling said AC waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said AC waveform for each of some of the AC cycles of said AC waveform; means for generating a value representing a change in magnitude with respect to time of said AC waveform from a pair of the digital samples of one of the AC cycles, trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said AC waveform and a predetermined threshold; capture means for capturing said digital samples of said AC waveform in response to said trigger signal; and wherein the digital samples of said means cooperating with said sampling means includes a plurality of the digital samples before said trigger signal and a plurality of the digital samples after said trigger signal. - View Dependent Claims (12)
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13. An apparatus for monitoring an electric power system including a waveform, said apparatus, comprising:
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sensing means for sensing said waveform; sampling means for sampling said waveform sensed by said sensing means; means cooperating with said sampling means for providing a plurality of digital samples of said waveform; means for generating a value representing a change in magnitude with respect to time of said waveform from an adjacent pair of the digital samples; trigger means for generating at least one trigger signal, with said trigger signal being a function of said value representing a change in magnitude with respect to time of said waveform and a predetermined threshold; capture means for capturing said digital samples of said waveform in response to said trigger signal; and wherein said waveform is an alternating current (AC) waveform having a plurality of AC cycles;
wherein said means cooperating with said sampling means includes means for providing said digital samples with a periodic time interval between the adjacent pair of said digital samples; and
wherein said means for generating a value includes means for comparing the adjacent pair of said digital samples to determine said value representing a change in magnitude with respect to time within one of the AC cycles of said AC waveform.
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Specification