Intelligent electronic device with constant calibration capabilities for high accuracy measurements
First Claim
1. An intelligent electronic device (IED) comprising:
- at least one sensor configured to measure at least one parameter of an electrical distribution system and output a signal indicative of the measured at least one parameter;
a reference source configured to provide at least three reference voltage signals, each of the at least three reference voltage signals having a different predetermined value;
at least one switch configured to receive the output signal of the at least one sensor and the at least three reference voltage signals and to selectively output the received signals, sequentially and repeatedly;
at least one analog-to-digital converter configured to receive the selectively outputted signals, sequentially sample each of the selectively outputted signals, and convert each sample to a digital sample; and
at least one processing device configured to determine a gain and an offset based on the samples of the at least three reference voltage signals, wherein the offset is a middle value of the at least three reference voltage values and the gain is calculated using the following formula;
gain=(a range of a highest reference signal value to the lowest reference signal value)/(highest measured reference signal value−
lowest measured reference signal value), andthe at least one processing device is further configured to calibrate each of the samples of the outputted signal of the at least one sensor with the gain and offset based on the samples of the at least three reference voltage signals.
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Accused Products
Abstract
An intelligent electronic device with constant calibration capabilities for high accuracy measurements and method thereof are provided. The intelligent electronic device presented herein constantly samples the output of at least one signal from a sensor and at least three reference signals, where the reference signals include a high reference signal, a low reference signal, and a medium reference signal. Using the constant calibration implementations provided, the intelligent electronic device can calibrate and compensate a signal from a sensor in real time. The constant calibration implementations provided are independent of time and temperature, and are advantageous in a rapidly changing environment. Furthermore, the constant calibration implementations provided enable the intelligent electronic device to track changes in an applied correction factor for traceability in the error correction process. The intelligent electronic device can determine, when the correction factor is applied, how often, and temporary drifts in accuracy.
352 Citations
28 Claims
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1. An intelligent electronic device (IED) comprising:
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at least one sensor configured to measure at least one parameter of an electrical distribution system and output a signal indicative of the measured at least one parameter; a reference source configured to provide at least three reference voltage signals, each of the at least three reference voltage signals having a different predetermined value; at least one switch configured to receive the output signal of the at least one sensor and the at least three reference voltage signals and to selectively output the received signals, sequentially and repeatedly; at least one analog-to-digital converter configured to receive the selectively outputted signals, sequentially sample each of the selectively outputted signals, and convert each sample to a digital sample; and at least one processing device configured to determine a gain and an offset based on the samples of the at least three reference voltage signals, wherein the offset is a middle value of the at least three reference voltage values and the gain is calculated using the following formula;
gain=(a range of a highest reference signal value to the lowest reference signal value)/(highest measured reference signal value−
lowest measured reference signal value), andthe at least one processing device is further configured to calibrate each of the samples of the outputted signal of the at least one sensor with the gain and offset based on the samples of the at least three reference voltage signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An intelligent electronic device (IED) comprising:
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at least one sensor configured to measure at least one parameter of an electrical distribution system and output a signal indicative of the measured at least one parameter; a reference source configured to provide at least three reference voltage signals, each of the at least three reference voltage signals having a different predetermined value; at least one switch configured to receive the output signal of the at least one sensor and the at least three reference voltage signals and to selectively output the received signals, sequentially and repeatedly; at least one analog-to-digital converter configured to receive the selectively outputted signals, sequentially sample each of the selectively outputted signals according to a sampling rate, wherein the sampling rate equals; (a predetermined sampling rate of the IED) x (1 +the number of reference voltage signals), and the at least one analog-to-digital converter is further configured to convert each sample to a digital sample; and at least one processing device configured to calibrate each of the samples of the outputted signal of the at least one sensor based on the samples of the at least three reference voltage signals. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. An intelligent electronic device (IED) comprising:
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at least one sensor configured to measure at least one parameter of an electrical distribution system and output a signal indicative of the measured at least one parameter; a reference source configured to provide at least two reference voltage signals, each of the at least two reference voltage signals having a different predetermined value; at least one switch configured to receive the output signal of the at least one sensor and the at least two reference voltage signals and to selectively output the received signals, sequentially and repeatedly; at least one analog-to-digital converter configured to receive the selectively outputted signals, sequentially sample each of the selectively outputted signals, and convert each sample to a digital sample; and at least one processing device configured to determine a gain based on the samples of the at least two reference voltage signals, wherein the gain is calculated using the following formula;
gain=(a range of a highest reference signal value to the lowest reference signal value)/(highest measured reference signal value−
lowest measured reference signal value), andthe at least one processing device is further configured to calibrate each of the samples of the outputted signal of the at least one sensor with the gain based on the samples of the at least two reference voltage signals. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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Specification