Distributed current and voltage sampling function for an electric power monitoring unit
First Claim
1. A controller suitable for monitoring electrical power lines which transmit alternating current electric power including a periodic voltage component and a periodic current component, having a predetermined frequency, to a load circuit, said apparatus comprising:
- current sampling means for digitally sampling the current component of the power during a single period thereof, at a rate which produces a number of digital samples sufficient to resolve the current component to the Nth harmonic of said predetermined frequency during each period of said periodic current component, where N is an integer greater than 2; and
voltage sampling means for digitally sampling the voltage component of the power, during a sampling interval which includes multiple periods of the voltage component, at a rate less than the rate used to sample the current component to produce a number of digital samples sufficient to resolve the voltage component to the Mth harmonic of said predetermined frequency during the sampling interval, where M is an integer greater than 2.
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Accused Products
Abstract
A low voltage AC electric power monitoring system includes a processor which samples the current and circuit breaker system includes a processor which samples each of the current components at seventeen samples per cycle to obtain current samples representing a single period of the AC power signal. The processor samples the voltage component at different points in the voltage cycle over several cycles to obtain voltage samples representing a single period of the AC power signal.
141 Citations
6 Claims
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1. A controller suitable for monitoring electrical power lines which transmit alternating current electric power including a periodic voltage component and a periodic current component, having a predetermined frequency, to a load circuit, said apparatus comprising:
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current sampling means for digitally sampling the current component of the power during a single period thereof, at a rate which produces a number of digital samples sufficient to resolve the current component to the Nth harmonic of said predetermined frequency during each period of said periodic current component, where N is an integer greater than 2; and voltage sampling means for digitally sampling the voltage component of the power, during a sampling interval which includes multiple periods of the voltage component, at a rate less than the rate used to sample the current component to produce a number of digital samples sufficient to resolve the voltage component to the Mth harmonic of said predetermined frequency during the sampling interval, where M is an integer greater than 2. - View Dependent Claims (2, 3, 4)
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5. A controller suitable for monitoring electric power lines which transmit multi-phase alternating current electric power to a load circuit, wherein each power phase includes a periodic voltage component and a periodic current component, having a common frequency, said controller comprising:
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means for digitally sampling the current component of each phase of the power during a single period thereof, at a rate which produces a number of samples sufficient to resolve the current component of each power phase to the Nth harmonic of the common frequency during each period of said periodic current component, where N is an integer greater than 2; and means for digitally sampling the voltage component of each phase of the power, during a sampling interval which includes multiple periods of the voltage component, at a rate less than the rate used to sample the current component to produce, during each sampling interval, a number of digital samples sufficient to resolve the voltage component of each phase of the power to the Mth harmonic of the common frequency, where M is an integer greater than 2.
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6. A controller suitable for monitoring electrical power lines which transmit alternating current electric power including a periodic voltage component and a periodic current component, having a predetermined frequency, to a load circuit, said apparatus comprising:
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first sampling means for digitally sampling one of the respective current and voltage components of the power during a single period thereof, at a rate which produces a number of digital samples sufficient to resolve said one component to the Nth harmonic of said predetermined frequency during each period of said one periodic component, where N is an integer greater than 2; and second sampling means for digitally sampling the other component of the power, during a sampling interval which includes multiple periods of said other component, at a rate less than the rate used to sample said one component, to produce a number of digital samples sufficient to resolve said other component to the Mth harmonic of said predetermined frequency during the sampling interval, where M is an integer greater than 2.
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Specification