Method and apparatus to diagnose current sensor polarities and phase associations for a three-phase electric power system

• US 10,088,546 B2
• Filed: 05/01/2014
• Issued: 10/02/2018
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Inventors: Gao, Zhi, Zaremski, Brian Zachary, Hayashi, Alan Kenji
• Primary Examiner(s): Astacio-Oquendo, Giovanni
• Application Number:
  US14/267,451
• Publication Number:
  US 20150042311A1
• Time in Patent Office: 1,615 Days
• Field of Search: 324107, 324 7611, 324 7652, 324 7659, 324 7661, 324 7677, 702 57, 702 60
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 25/00 Arrangements for measuring phase angle between a voltage and a current or between voltages or currents
• CPC Class Codes: G01R 31/67 Testing the correctness of wire connections in electric apparatus or circuits
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence

Abstract

A system for a three-phase electric power system includes a plurality of voltage sensors sensing three-phase voltages of the three-phase electric power system; a plurality of current sensors sensing three-phase currents of the three-phase electric power system; and a number of analog-to-digital converters converting the sensed three-phase voltages and the sensed three-phase currents of the three-phase electric power system to corresponding digital values. A processor calculates from the corresponding digital values at least two phase angles between voltage and current for at least two of three phases of the three-phase electric power system, diagnoses polarities and phase associations for at least two of the current sensors based on, for each of the at least two current sensors, a predetermined wiring configuration of the three-phase electric power system and a corresponding one of the at least two phase angles being within a corresponding predetermined angular range, and outputs corresponding diagnosis results.

Claims

1. A system for a three-phase electric power system having three phases, said system comprising:

a plurality of voltage sensors structured to sense three-phase voltages of said three-phase electric power system;

a plurality of current sensors structured to sense three-phase currents of said three-phase electric power system;

a number of analog-to-digital converters structured to convert the sensed three-phase voltages and the sensed three-phase currents of said three-phase electric power system to corresponding digital values; and

a processor configured and programmed to calculate from the corresponding digital values at least two phase angles between voltage and current for at least two of said three phases of said three-phase electric power system, determine a configuration for at least two of said plurality of current sensors based on, for each of said at least two of said plurality of current sensors, a predetermined wiring configuration of said three-phase electric power system and a corresponding one of the at least two phase angles being within a corresponding predetermined angular range, wherein the configuration for each of the at least two of said plurality of current sensors indicates a polarity for each of the at least two of said plurality of current sensors and a phase of the three-phase electric power system with which each of the at least two of said plurality of current sensors is associated, and output the determined configuration for each of the at least two of said plurality of current sensors.

2. The system of claim 1 wherein said processor is further configured and programmed to store the configuration for each of the at least two of said plurality of current sensors for use in troubleshooting or diagnostics of said system.

3. The system of claim 1 wherein said predetermined wiring configuration is a 3-phase 4-wire wye configuration.

4. The system of claim 1 wherein said predetermined wiring configuration is a 3-phase 3-wire delta configuration.

5. The system of claim 1 wherein said predetermined wiring configuration is a 3-phase 3-wire inside delta configuration.

6. The system of claim 1 wherein said predetermined wiring configuration is a 3-phase 4-wire delta configuration.

7. The system of claim 1 wherein said predetermined wiring configuration is a 3-phase corner-grounded delta configuration.

8. The system of claim 1 wherein said processor is part of an electric power meter, an electric energy meter or a protective relay of said three-phase electric power system.

9. The system of claim 1 wherein said processor is further configured and programmed to diagnose for each of said plurality of current sensors whether a corresponding one of said plurality of current sensors has a correct polarity and is associated with a correct one of the three phases of said three-phase electric power system.

10. The system of claim 1 wherein said processor is configured and programmed to output the determined configuration for each of said at least two of said plurality of current sensors by outputting for each of said at least two of the three phases of said three-phase electric power system:

(a) the corresponding one of the at least two phase angles; and

(b) an indication of whether a corresponding one of the plurality of current sensors has a correct polarity and is operatively associated with a correct one of the three phases of said three-phase electric power system.

11. A method for a three-phase electric power system having three phases, said method comprising:

sensing three-phase voltages of said three-phase electric power system;

employing current sensors and sensing three-phase currents of said three-phase electric power system;

converting the sensed three-phase voltages and the sensed three-phase currents of said three-phase electric power system to corresponding digital values;

calculating from the corresponding digital values at least two phase angles between voltage and current for at least two of said three phases of said three-phase electric power system; and

determining with a processor a configuration for at least two of said current sensors based on, for each of said at least two of said current sensors, a predetermined wiring configuration of said three-phase electric power system and a corresponding one of the at least two phase angles being within a corresponding predetermined angular range, wherein the configuration for each of the at least two of said current sensors indicates a polarity for each of the at least two of said current sensors and a phase of the three-phase electric power system with which each of the at least two of said current sensors is associated, and outputting the determined configuration for each of the at least two of said current sensors.

12. The method of claim 11 further comprising:

employing a 3-phase 4-wire wye configuration as said predetermined wiring configuration.

13. The method of claim 11 further comprising:

employing a 3-phase 3-wire delta configuration as said predetermined wiring configuration.

14. The method of claim 11 further comprising:

employing a 3-phase 3-wire inside delta configuration as said predetermined wiring configuration.

15. The method of claim 11 further comprising:

employing a 3-phase 4-wire delta configuration as said predetermined wiring configuration.

16. The method of claim 11 further comprising:

employing a 3-phase corner-grounded delta configuration as said predetermined wiring configuration.

17. The method of claim 11 further comprising:

employing said processor as part of an electric power meter, an electric energy meter or a protective relay of said three-phase electric power system.

18. The method of claim 11 further comprising:

diagnosing for each of said current sensors whether a corresponding one of said current sensors has a correct polarity and is associated with a correct one of said three phases of said three-phase electric power system.

19. The method of claim 11 further comprising:

displaying said determined configuration for each of the at least two of said current sensors by including in the displaying;

(a) the corresponding one of the at least two phase angles; and

(b) an indication of whether a corresponding one of the current sensors has a correct polarity and is operatively associated with a correct one of said three phases of said three-phase electric power system.

20. The method of claim 11 further comprising:

displaying said determined configuration for each of the at least two of said current sensors by including in the displaying;

(a) an indication of whether a corresponding one of the current sensors has a correct polarity and is operatively associated with a correct one of the three phases;

or (b) a number of corrective actions for a corresponding number of the current sensors.

21. The method of claim 20 further comprising:

employing as the number of the corrective actions for the corresponding number of the current sensors at least one of;

(i) swapping two of the current sensors for two of the three phases; and

(ii) reversing one of the current sensors for one of the three phases.