METHOD AND APPARATUS TO DIAGNOSE CURRENT SENSOR POLARITIES AND PHASE ASSOCIATIONS FOR A THREE-PHASE ELECTRIC POWER SYSTEM

• US 20150042311A1
• Filed: 05/01/2014
• Published: 02/12/2015
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: GAO, ZHI, ZAREMSKI, BRIAN ZACHARY, HAYASHI, ALAN KENJI
• Granted Patent: US 10,088,546 B2
• Time in Patent Office: Days
• US Class Current: 324/107
• 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, 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 structured to calculate from the corresponding digital values at least two phase angles between voltage and current for at least two of three phases of said three-phase electric power system, diagnose polarities and phase associations for at least two of said current sensors based on, for each of said at least two 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, and output corresponding diagnosis results.

2. The system of claim 1 wherein said processor is further structured to store the corresponding diagnosis results 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 structured to diagnose 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 the three phases of said three-phase electric power system.

10. The system of claim 1 wherein said output corresponding diagnosis results includes for each of said at least two of the three phases:

(a) the corresponding one of the 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 the three phases.

11. A method for a three-phase electric power system, 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 three phases of said three-phase electric power system; and

diagnosing with a processor polarities and phase associations for at least two of said current sensors based on, for each of said at least two 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, and outputting corresponding diagnosis results.

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 the three phases of said three-phase electric power system.

19. The method of claim 11 further comprising:

displaying said output corresponding diagnosis results including for each of said at least two of the three phases;

(a) the corresponding one of the 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 the three phases.

20. The method of claim 11 further comprising:

displaying said output corresponding diagnosis results including for each of said at least two of the three phases;

(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.