Intelligent electronic device and method thereof

• US 8,620,608 B2
• Filed: 12/09/2011
• Issued: 12/31/2013
• Est. Priority Date: 01/27/2005
• Status: Active Grant

• Current Assignee: EI Electronics LLC (Hubbell, Inc.)
• Original Assignee: Electro Industries/Gaugetech
• Inventors: Banhegyesi, Tibor, Kagan, Erran, Banker, Patricia E.
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US13/315,521
• Publication Number:
  US 20120078555A1
• Time in Patent Office: 753 Days
• Field of Search: 702/62, 702/64, 702/66, 324/113, 324/142
• US Class Current: 702/64
• CPC Class Codes: G01D 4/004 Remote reading of utility meters to a fixed location
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 22/10 using digital techniques
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

An intelligent electronic device (IED) having a gain control unit adapted to selectively regulate operating ranges of output signals of a sensing circuit of the device is described. In one embodiment, the IED is a digital electric power and energy meter, which operating ranges for supply voltages and supply currents of electrical services may be adjusted to match pre-determined ranges for input signals of a data acquisition system or a data processing module of the meter.

Claims

1. An intelligent electronic device, comprising:

a metering module that measures at least one parameter of an AC electrical service; and

a processing module that processes the at least one parameter obtained using the metering module;

wherein the metering module samples supply voltages or supply currents of the AC electrical service at frequency-locked points to obtain frequency-locked samples, the frequency-locked points relating to zero-crossing points of the supply voltages or supply currents of the AC electrical service, the frequency-locked samples being obtained a predetermined number of times per cycle; and

wherein the metering module samples the supply voltages or supply currents of the AC electrical service at time-locked points to obtain time-locked samples, the time-locked points being independent of the frequency-locked points and corresponding to predetermined moments of time during a predetermined time interval.

2. The intelligent electronic device of claim 1, wherein the processing module further comprises

a first buffer that stores the frequency-locked samples;

and

a second buffer that stores the time-locked samples.

3. The intelligent electronic device of claim 2, wherein the processing module synchronizes the frequency-locked samples stored in the first buffer with the time-locked samples stored in the second buffer.

4. The intelligent electronic device of claim 1, wherein the processing module performs harmonic analysis on the frequency-locked samples.

5. The intelligent electronic device of claim 1, wherein the processing module performs energy calculations on the frequency-locked samples.

6. The intelligent electronic device of claim 1, wherein the processing module performs waveform analysis on the time-locked samples.

7. The intelligent electronic device of claim 1, wherein the zero-crossing points are moments of time when a polarity of the supply voltages or the supply currents changes from a negative polarity to a positive polarity or when a polarity of the supply voltages or the supply currents changes from a positive polarity to a negative polarity.

8. The intelligent electronic device of claim 1, further comprising a user interface unit that displays the at least one parameter, frequency-locked samples, time-locked samples, data processed by the processing module, or configuration settings of the intelligent electronic device.

9. The intelligent electronic device of claim 1, further comprising a communication module that transmits, to a remote terminal, the at least one parameter, frequency-locked samples, time-locked samples, data processed by the processing module, or configuration settings of the intelligent electronic device.

10. The intelligent electronic device of claim 1, wherein said intelligent electronic device is selected from the group consisting of a digital electrical power and energy meter, a Programmable Logic Controller (PLC), a Remote Terminal Unit, a protective relay, or a fault recorder.

11. The intelligent electronic device of claim 1, wherein said intelligent electronic device is a digital electrical power and energy meter.

12. The intelligent electronic device of claim 1, wherein the metering module comprises a voltage analog-to-digital converter and a current analog-to-digital converter, the voltage analog-to-digital converter and current analog-to-digital converter being synchronized with each other using the zero-crossing points.

13. The intelligent electronic device of claim 1, wherein the processing module comprises at least one voltage analog-to-digital converter and at least one current analog-to-digital converter, the at least one voltage analog-to-digital converter and at least one current analog-to-digital converter being synchronized with each other using the zero-crossing points.

14. A method of using an intelligent electronic device to measure and process at least one parameter of an AC electrical service, the method comprising the steps of:

sampling supply voltages or supply currents of the AC electrical service at frequency-locked points using a metering module to obtain frequency-locked samples, the frequency-locked points relating to zero-crossing points of the supply voltages or supply currents of the AC electrical service, the frequency-locked samples being obtained a predetermined number of times per cycle; and

sampling the supply voltages or supply currents of the AC electrical service at time-locked points using the metering module to obtain time-locked samples, the time-locked points being independent of the frequency-locked points and corresponding to predetermined moments of time during a predetermined time interval.

15. The method of claim 14, wherein the zero-crossing points are moments of time when a polarity of the supply voltages or the supply currents changes from a negative polarity to a positive polarity or when a polarity of the supply voltages or the supply currents changes from a positive polarity to a negative polarity.

16. The method of claim 14, wherein the at least one parameter is a total harmonic distortion or harmonics thereof.

17. The method of claim 14, wherein the at least one parameter is selected from the group consisting of a line voltage, a line current, a phase voltage, a phase current, a root mean square (RMS) value, energy, revenue, real power, reactive power, total power, and a power factor.

18. The method of claim 14, wherein the at least one parameter is selected from the group consisting of a waveform of a line voltage, a waveform of a line current, a waveform of a phase voltage, and a waveform of a phase current.

19. The method of claim 14, further comprising the step of synchronizing a voltage analog-to-digital converter of the metering and a current analog-to-digital converter of the metering module using the zero-crossing points.

20. The method of claim 14, further comprising the step of processing the at least one parameter, frequency-locked samples, and time-locked samples using a processing module.

21. The method of claim 20, further comprising the step of synchronizing at least one voltage analog-to-digital converter of the processing module and at least one current analog-to-digital converter of the processing module with each other using the zero-crossing points.