Automated precision alignment of data in a utility monitoring system
First Claim
1. A method of aligning data measured by monitoring devices coupled to a power monitoring system, comprising:
- receiving reference signal data from a reference monitoring device, said reference signal data representing at least frequency variations measured by said reference monitoring device for a predetermined number of cycles;
receiving second signal data from at least a second monitoring device, said second signal data representing at least frequency variations measured by said second monitoring device for a predetermined number of cycles; and
automatically aligning said reference signal data with said second signal data.
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Abstract
A data alignment algorithm that automatically aligns data from multiple monitoring devices to the same zero-crossings at the same point in time. Cycle-by-cycle frequency data is received from each monitoring device and a cross-correlation algorithm is performed to determine a correlation coefficient between a reference monitoring device and another monitoring device. The data of the other monitoring device is shifted by one cycle and another correlation coefficient is calculated by the cross-correlation algorithm. The data of the two monitoring devices is aligned at the point at which the maximum correlation coefficient is calculated or the point at which the correlation coefficient exceeds a threshold value. The clocks of the monitoring devices can also be synchronized at the same point of alignment.
59 Citations
25 Claims
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1. A method of aligning data measured by monitoring devices coupled to a power monitoring system, comprising:
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receiving reference signal data from a reference monitoring device, said reference signal data representing at least frequency variations measured by said reference monitoring device for a predetermined number of cycles;
receiving second signal data from at least a second monitoring device, said second signal data representing at least frequency variations measured by said second monitoring device for a predetermined number of cycles; and
automatically aligning said reference signal data with said second signal data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of aligning data in a power monitoring system, comprising:
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receiving from a first of at least two monitoring devices first signal data corresponding to signal data stored by said first monitoring device, said first signal data representing frequency or amplitude variations;
receiving from a second of said at least two monitoring devices second signal data corresponding to signal data stored by said second monitoring device, said second signal data representing frequency or amplitude variations; and
aligning said first signal data with said second signal data by shifting in increments said second signal data relative to said first signal data until a maximum cross-correlation coefficient is computed by a cross-correlation function that calculates a cross-correlation coefficient at each of said increments. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A power monitoring system for aligning data, comprising:
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a system controller;
a first monitoring device having a communications interface coupled to said system controller, a memory, and a controller; and
a second monitoring device having a communications interface coupled to said system controller, a memory, and a controller, wherein said system controller is programmed to communicate an instruction to said first monitoring device and said second monitoring device via their respective communications interfaces to store in their respective memories data representing one or both of frequency variations and amplitude variations on a cycle-by-cycle basis for a predetermined number of cycles, receive from said first monitoring device first data corresponding to said data stored by said first monitoring device in its memory, receive from said second monitoring device second data corresponding to said data stored by said second monitoring device in its memory, and align said first data with said second data by shifting in cycle increments said second data relative to said first data until a maximum cross-correlation coefficient is computed by a cross-correlation function that computes a cross-correlation coefficient at each of said cycle increments, and wherein said controller of said first monitoring device is programmed to receive said instruction via said communication interface of said first monitoring device, store said first data in said memory of said first monitoring device for said predetermined number of cycles, communicate said first data to said system controller via said communication interface. - View Dependent Claims (25)
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Specification