US5736847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power meter for determining parameters of muliphase power lines
Assignee: Power Measurement Ltd
•
Filing: 1994-12-30
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Granted: 1998-04-07
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Expires: 2014-12-30
Abstract
Abstract A power meter is disclosed for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment. The 3-phase voltage and current signals have a fundamental frequency. The power lines are connected to at least one transducer which generates analog signals representing the voltage and current signals. The power meter includes receiving circuitry which can be connected to the at least one transducer to receive the analog signals. An analog to digital converter receives the output signal from the receiving circuitry and converts the voltage and current signals to digital data representing the analog signals. A processor receives the digital data and includes logic for calculating the power parameters. The power meter compensates for errors caused by not sampling synchronous to the fundamental frequency of the signals.
Inventors
- 👤 Peter M. Van Doorn
- 👤 Simon H. Lightbody
- 👤 Chuen Shan Simon Ki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:22
CPC Classifications
G; G01; G01R; G01R21/00; G01R21/133; G01R21/1331; G01R19/00; G01R19/25
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
158 words
A power meter for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment, the 3-phase voltage and current signals having a fundamental frequency, the power lines having connected thereto at least one transducer generating analog signals representing the voltage and current signals, the power meter comprising: receiving circuitry, the receiving circuitry connectable to receive the analog signals from the at least one transducer and generate an output signal therefrom; an analog to digital converter operatively connected to receive the output signal from the receiving circuitry, sample said output signal at a sampling rate, and convert the voltage and current signals to digital data representing the analog signals; and a processor operatively connected to receive the digital data, the processor including logic means comprising: means for calculating the power parameters; and means for compensating for errors caused by not sampling synchronous to the fundamental frequency of the signals.
Claim 2
Dependent Claim
158 words
A power meter for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment, the 3-phase voltage and current signals having a fundamental frequency, the power lines having connected thereto at least one transducer generating analog signals representing the voltage and current signals, the power meter comprising: receiving circuitry, the receiving circuitry connectable to receive the analog signals from the at least one transducer and generate an output signal therefrom; an analog to digital converter operatively connected to receive the output signal from the receiving circuitry, sample said output signal at a sampling rate, and convert the voltage and current signals to digital data representing the analog signals; and a processor operatively connected to receive the digital data, the processor including logic means comprising: means for calculating the power parameters; and means for compensating for errors caused by not sampling synchronous to the fundamental frequency of the signals.
Claim 3
Dependent Claim
25 words
The power meter of claim 1 wherein said logic means further comprises: means for calculating at least one phasor of the voltage and current signals.
Claim 4
Dependent Claim
31 words
The power meter of claim 2 wherein said calculating means further comprises: means to compute the voltage and current phasors at each individual harmonic frequency of the voltage and current signals.
Claim 5
Dependent Claim
29 words
The power meter of claim 1 wherein said logic means further comprises: means to compute real and reactive power at each harmonic frequency of the voltage and current signals.
Claim 6
Dependent Claim
26 words
The power meter of claim 1 wherein said logic means further comprises: means for calculating at least one symmetrical component of the voltage and current signals.
Claim 7
Dependent Claim
54 words
The power meter of claim 1 including: conditioning circuitry to receive the voltage and current signals and simultaneously detect signals in a normal operating range and signals in an out of normal operating range; and wherein the logic means further comprises: means to calculate power parameters for the signals in the normal operating range.
Claim 8
Dependent Claim
24 words
The power meter of claim 6 wherein the logic means further comprises: means to calculate power parameters for the out of normal range signal.
Claim 9
Dependent Claim
28 words
The device of claim 1 wherein said logic means further comprises means for continuously adjusting the sampling rate to be near synchronous with the voltage and current signals.
Claim 10
Dependent Claim
40 words
The power meter of claim 1 wherein at least one of the receiving circuitry and the analog to digital converter introduces a phase shift error and wherein said logic means further comprises: means to compensate for the phase shift error.
Claim 11
Dependent Claim
21 words
The power meter of claim 1 wherein said logic means further comprises means for compensating for non-linearity in the receiving circuitry.
Claim 12
Dependent Claim
49 words
The power meter of claim 1 including a plugable circuit board including conditioning circuitry receiving said voltage and current signals and a memory containing calibration data such that the plugable circuit boards can be interchanged without loss of power meter accuracy, said conditioning circuitry connected to said receiving circuitry.
Claim 13
Dependent Claim
50 words
The power meter of claim 1 including a plugable circuit board including conditioning circuitry receiving said voltage and current signals and a memory containing configuration data such that the processor can detect the circuit configuration and adopt a correct mode of operation, said conditioning circuitry connected to said receiving circuitry.
Claim 14
Dependent Claim
155 words
A power meter for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment, the power lines having connected thereto at least one transducer generating analog signals representing the voltage and current signals, the power meter comprising: receiving circuitry, the receiving circuitry connectable to receive the analog signals from the at least one transducer and generate an output signal therefrom; an analog to digital converter operatively connected to receive the output signal from the receiving circuitry, sample the output signal at a sampling rate, and convert the voltage and current signals to digital data representing the analog signals; and a processor operatively connected to receive the digital data, the processor including logic means comprising: means for calculating at least one phasor of the voltage and current signals; and means for continuously adjusting the sampling rate to be near synchronous with the voltage and current signals.
Claim 15
Dependent Claim
155 words
A power meter for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment, the power lines having connected thereto at least one transducer generating analog signals representing the voltage and current signals, the power meter comprising: receiving circuitry, the receiving circuitry connectable to receive the analog signals from the at least one transducer and generate an output signal therefrom; an analog to digital converter operatively connected to receive the output signal from the receiving circuitry, sample the output signal at a sampling rate, and convert the voltage and current signals to digital data representing the analog signals; and a processor operatively connected to receive the digital data, the processor including logic means comprising: means for calculating at least one phasor of the voltage and current signals; and means for continuously adjusting the sampling rate to be near synchronous with the voltage and current signals.
Claim 16
Dependent Claim
31 words
The power meter of claim 13 wherein said calculating means further comprises means to compute the voltage and current phasors at each individual harmonic frequency of the voltage and current signals.
Claim 17
Dependent Claim
29 words
The power meter of claim 13 wherein said calculating means further comprises means to compute real and reactive power at each harmonic frequency of the voltage and current signals.
Claim 18
Dependent Claim
26 words
The power meter of claim 13 wherein said calculating means further comprises means for calculating at least one symmetrical component of the voltage and current signals.
Claim 19
Dependent Claim
54 words
The power meter of claim 13 including: conditioning circuitry to receive the voltage and current signals and simultaneously detect signals in a normal operating range and signals in an out of normal operating range; and wherein the logic means further comprises means to calculate power parameters for the signals in the normal operating range.
Claim 20
Dependent Claim
24 words
The power meter of claim 17 wherein the logic means further comprises means to calculate power parameters for the out of normal range signal.
Claim 21
Dependent Claim
40 words
The power meter of claim 13 wherein at least one of the receiving circuitry and the analog to digital converter introduces a phase shift error and wherein said logic means further comprises means to compensate for the phase shift error.
Claim 22
Dependent Claim
21 words
The power meter of claim 13 wherein said logic means further comprises means for compensating for non-linearity in the receiving circuitry.
Claim 23
Dependent Claim
49 words
The power meter of claim 13 including a plugable circuit board including conditioning circuitry receiving said voltage and current signals and a memory containing calibration data such that the plugable circuit boards can be interchanged without loss of power meter accuracy, said conditioning circuitry connected to said receiving circuitry.
Claim 24
Dependent Claim
47 words
The power meter of claim 13 including a plugable circuit board including conditioning circuitry receiving input signals and a memory containing configuration data such that the processor can detect the circuit configuration and adopt a correct mode of operation, said conditioning circuitry connected to said receiving circuitry.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-06 | 2001-10-06 | 2002-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-06 | 2005-10-06 | 2006-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-06 | 2009-10-06 | 2010-04-07 | $7700.00 | Window Closed / Lapsed |