System and Method for Multi-Rate Concurrent Waveform Capture and Storage for Power Quality Metering

• US 20090012728A1
• Filed: 09/16/2008
• Published: 01/08/2009
• Est. Priority Date: 01/27/2005
• Status: Active Grant

• Current Assignee: EI Electronics LLC (Hubbell, Inc.)
• Original Assignee: Electro Industries/Gaugetech
• Inventors: Zhu, Hai, Spanier, Joseph, Slota, Frederick B.
• Granted Patent: US 8,121,801 B2
• Time in Patent Office: Days
• US Class Current: 702/61
• CPC Class Codes: G01R 19/04 Measuring peak values or amplitude or envelope of ac or of pulses
• CPC Class Codes: G01R 19/2509 Details concerning sampling, digitizing or waveform capturing
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: G01R 29/02 Measuring characteristics of individual pulses, e.g. deviation from pulse flatness, rise time or duration
• CPC Class Codes: G06F 17/40 Data acquisition and logging for input to computer G06F3/00
• CPC Class Codes: G06F 7/76 Arrangements for rearranging, permuting or selecting data according to predetermined rules, independently of the content of the data
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

Systems and methods are provided for use in an IED that perform high resolution waveform capture to generate multi-rate waveform data in real-time. In one embodiment, high-resolution sampled data is dynamically pre-ordered into separate high resolution and low resolution data streams for presentation and storage. This pre-ordering of data is optimized so as to minimize the amount of data manipulation required to prepare the sampled data for eventual presentation and storage in the IED. Pre-ordering of data facilitates minimum performance impact so that continuous real-time data capture can be achieved.

Claims

1. In an intelligent electronic device a method of performing high resolution waveform capture to generate multi-rate waveform data in real-time, the method comprising the steps of:

setting a desired first (low) sample rate; and

pre-ordering a processed digital stream in real-time to create multi-rate waveform data comprised of a low resolution data stream and a high resolution data stream.

2. Method according to claim 1, wherein the low resolution data stream is comprised of low resolution samples of the pre-ordered processed digital stream at the desired first (low) sample rate and wherein the high resolution data stream is comprised of high resolution samples of the pre-ordered processed digital stream at a second (high) sample rate.

3. In an intelligent electronic device a method of performing high resolution waveform capture to generate multi-rate waveform data in real-time, the method comprising the steps of:

setting a desired first sample rate; and

pre-ordering a processed digital stream in real-time to create multi-rate waveform data comprised of a first data stream at a first sampling rate and a second data stream at a second sampling rate.

4. Method according to claim 3, wherein the first data stream is comprised of samples of the pre-ordered processed digital stream at the desired first sample rate and wherein the second data stream is comprised of samples of the pre-ordered processed digital stream at a second sample rate.

5. In an intelligent electronic device a method of performing high resolution waveform capture to generate multi-rate waveform data in real-time, the method comprising the steps of:

a) setting a desired first sample rate;

b) reading an input digital stream of data comprised of a plurality of time-ordered samples sampled at a second sample rate;

c) processing the input digital stream to generate a processed digital stream; and

d) pre-ordering the processed digital stream in real-time as it is being written to the memory to create multi-rate waveform data comprised of a low resolution data stream comprised of low resolution samples from among samples of the input digital stream at said first sample rate and a high resolution data stream comprised of high resolution samples from among samples of the input digital stream at said second sample rate.

6. Method according to claim 5, wherein the high resolution samples of the high resolution data stream do not include the low resolution samples from among the input digital stream.

7. Method according to claim 5, wherein the high resolution samples of the high resolution data stream include the low resolution samples from among the input digital stream.

8. Method according to claim 5, where the second sample rate of the high resolution data stream is an integer multiple of the sample rate of the first sample rate of the low resolution data stream.

9. Method according to claim 5, wherein said pre-ordering step (e) further comprises:

remapping addresses for writing the processed digital stream to the memory device in a temporal sequential order with alternate addresses for writing the processed digital stream to the memory in a non-temporal non-sequential order.

10. Method according to claim 5, further comprising:

storing the low resolution samples in a first memory buffer as low-resolution multi-rate waveform data; and

storing the high resolution samples in a second memory buffer as high-resolution multi-rate waveform data.

11. Method according to claim 5, further comprising:

receiving a conditioned analog stream; and

converting the conditioned analog stream to the input digital stream.

12. Method according to claim 11, wherein the conditioned analog stream is a three phase power source.

13. In an intelligent electronic device a method of performing high resolution waveform capture to generate multi-rate waveform data in real-time, the method comprising the steps of:

a) setting a desired first sample rate;

b) reading an input digital stream comprised of a plurality of time-ordered samples sampled at a second sample rate;

c) processing the digital stream of data to generate a processed digital stream of data comprised of a plurality of time ordered digital samples;

d) storing the processed digital stream of data in a memory;

e) pre-ordering the processed digital stream in real-time as it is being read from the memory to create multi-rate waveform data comprised of a low resolution data stream comprised of low resolution samples from among samples of the input digital stream at said first sample rate and a high resolution data stream comprised of high resolution samples from among samples of the input digital stream at said second sample rate.

14. Method according to claim 13, wherein the high resolution samples of the high resolution data stream do not include the low resolution samples from among the input digital stream.

15. Method according to claim 13, wherein the high resolution samples of the high resolution data stream include the low resolution samples from among the input digital stream.

16. Method according to claim 13, where the second (high) sample rate of the high resolution data stream is an integer multiple of the sample rate of the first (low) sample rate of the low resolution data stream.

17. Method according to claim 13, wherein said pre-ordering step (e) further comprises:

remapping addresses for reading the processed digital stream from the memory device in a temporal sequential order with alternate addresses for reading the processed digital stream from the memory in a non-temporal non-sequential order.

18. Method according to claim 13, further comprising:

storing the low resolution samples in a first memory buffer as low-resolution multi-rate waveform data; and

storing the high resolution samples in a second memory buffer as high-resolution multi-rate waveform data.

19. Method according to claim 13, further comprising:

receiving a conditioned analog stream; and

converting the conditioned analog stream to the input digital stream.

20. Method according to claim 19, wherein the conditioned analog stream is a three phase power source.

21. An intelligent electronic device comprising:

means for setting a desired first sample rate;

means for reading an input digital stream of data comprised of a plurality of time-ordered samples sampled at a second sample rate;

means for processing the input digital stream to generate a processed digital stream; and

means for pre-ordering the processed digital stream in real-time as it is being written to the memory to create multi-rate waveform data comprised of a low resolution data stream comprised of low resolution samples from among samples of the input digital stream at said first sample rate and a high resolution data stream comprised of high resolution samples from among samples of the input digital stream at said second sample rate.

22. Intelligent electronic device according to claim 21, wherein the high resolution samples of the high resolution data stream do not include the low resolution samples from among the input digital stream.

23. Intelligent electronic device according to claim 21, wherein the high resolution samples of the high resolution data stream include the low resolution samples from among the input digital stream.

24. Intelligent electronic device according to claim 21, where the second sample rate of the high resolution data stream is an integer multiple of the sample rate of the first sample rate of the low resolution data stream.

25. Intelligent electronic device according to claim 21, wherein said means for pre-ordering further comprises:

means for remapping addresses for writing the processed digital stream to the memory device in a temporal sequential order with alternate addresses for writing the processed digital stream to the memory in a non-temporal non-sequential order.

26. Intelligent electronic device according to claim 21, further comprising:

a first memory buffer for storing the low resolution samples as low-resolution multi-rate waveform data; and

a second memory buffer for storing the high resolution samples as high-resolution multi-rate waveform data.

27. Intelligent electronic device according to claim 21, further comprising:

receiving a conditioned analog stream; and

converting the conditioned analog stream to the input digital stream.

28. Intelligent electronic device according to claim 27, wherein the conditioned analog stream is a three phase power source.

29. An intelligent electronic device comprising:

at least one analog-to-digital converter for sampling waveform data;

a field programmable gate array (FPGA) for controlling the at least one analog-to-digital converter to sample the waveform data and for reading the sampled waveform data from the at least one analog-to-digital converter and for writing the sampled waveform data to a digital signal processor;

the digital signal processor for receiving the sampled waveform data from the FPGA, for processing the received sampled waveform data and for storing the processed sampled waveform data in a memory;

the memory for storing the processed sampled waveform data received from the digital signal processor; and

a processor for reading the processed data from the memory for further processing, presentation and storage.

30. The intelligent electronic device of claim 29, wherein the memory is divided into two zones by the FPGA, a first zone dedicated to storing high bandwidth data and a second zone dedicated to storing low bandwidth data.

31. The intelligent electronic device of claim 29, wherein the memory is a dual port memory.

32. The intelligent electronic device of claim 29, wherein the FPGA is further configured to remap the processed data as pre-ordered data as it writes the data to the digital signal processor.

33. The intelligent electronic device of claim 29, wherein the FPGA is further configured to remap the processed data as pre-ordered data as it writes the data to the digital signal processor.

34. The intelligent electronic device of claim 29, wherein the processor is configured to create pre-ordered data upon reading the processed data from the dual port memory.

35. The intelligent electronic device of claim 29, wherein the digital signal processor remaps the processed sampled waveform data as it writes the data to the memory.