Method and device for analysing the quality of the electrical energy in a three-phase electric network

Patent metadata

Field	Value
Publication number	US-9625503-B2
Application number	US-201214348736-A
Country	US
Kind code	B2
Filing date	Oct 16, 2012
Priority date	Oct 19, 2011
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A method for analyzing quality of electrical energy in a three-phase electric network, the method including: measuring a set of electrical magnitudes, the set including one electrical magnitude per phase; forming a space vector from an instantaneous three-dimensional transformation of the set of measured electrical magnitudes; and determining a set including at least one parameter representative of the quality of the electrical energy in the three-phase electric network, according to the space vector.

First claim

The invention claimed is:

1. A method for analyzing quality of electrical energy in a three-phase electric power system to determine absence or presence of disturbance in the three-phase electric power system, the method comprising:
measuring a set of electrical quantities, the set including one electrical quantity per phase;
generating, by processing circuitry of an analyzing device, a space vector, which is a time-dependent complex number, from an instantaneous three-dimensional transformation of the set of measured electrical quantities, the space vector being generated over a sliding window; and
determining, by the processing circuitry, according to the generated space vector, a set including at least one parameter representative of the quality of the electrical energy in the three-phase electric power system to determine the absence or the presence of disturbance in the three-phase electric power system, the at least one parameter including a parameter representative of voltage flicker.

2. The method for analyzing according to claim 1 , wherein the at least one parameter representative of the quality of the electrical energy in the three-phase electric power system further includes at least one of:
a parameter representative of a voltage or current unbalance in the three-phase power system,
a parameter representative of a voltage or current sag, and
a parameter representative of a voltage surge or of an overcurrent.

3. The method for analyzing according to claim 1 , further comprising generating a zero sequence component from the instantaneous three-dimensional transformation of the set of measured electrical quantities.

4. The method for analyzing according to claim 3 , wherein the determining the set including the at least one parameter representative of the quality of the electrical energy in the three-phase electric power system is further performed according to the zero sequence component, and the at least one parameter represents a harmonic voltage or current pollution.

5. The method for analyzing according to claim 3 , further comprising determining at least one energy parameter of the three-phase electric power system according to the space vector and the zero sequence component.

6. The method for analyzing according to claim 5 , wherein the at least one energy parameter includes at least one of:
a total rms current or voltage value,
a total three-phase active power,
a total three-phase apparent power, and
a total three-phase reactive power.

7. The method for analyzing according to claim 1 , further comprising displaying a shape followed by the space vector in the complex plane.

8. The method for analyzing according to claim 7 , further comprising:
analyzing, by processing circuitry of the analyzing device, a deviation in the shape followed by the space vector, a degree of deviation in the shape corresponding to a level of disturbance in the three-phase electric power system.

9. The method for analyzing according to claim 1 , wherein the sliding window has a time duration of 200 milliseconds.

10. A device for analyzing quality of electrical energy in a three-phase electric power system, the device comprising:
processing circuitry configured to
measure a set of electrical quantities, the set including one electrical quantity per phase,
generate a space vector, which is a time-dependent complex number, from an instantaneous three-dimensional transformation of the set of measured electrical quantities, the space vector being generated over a sliding window, and
determine, according to the generated space vector, a set including at least one parameter representative of the quality of the electrical energy in the three-phase electric power system, the at least one parameter including a parameter representative of voltage flicker.

11. The device for analyzing according to claim 10 , wherein the at least one parameter representative of the quality of the electrical energy in the three-phase electric power system further includes at least one of:
a parameter representative of a voltage or current unbalance in the three-phase power system,
a parameter representative of a voltage or current sag, and
a parameter representative of a voltage surge or an overcurrent.

12. The device for analyzing according to claim 10 , wherein the processing circuitry is further configured to generate a zero sequence component from the instantaneous three-dimensional transformation of the set of measured electrical quantities.

13. The device for analyzing according to claim 12 , wherein the processing circuitry that determines the set including the at least one parameter representative of the quality of the electrical energy in the three-phase electric power system is configured to further determine the set according to the zero sequence component and is further configured to determine a parameter representative of a harmonic voltage or current pollution.

14. The device for analyzing according to claim 12 , wherein the processing circuitry is further configured to determine at least one energy parameter of the three-phase electric power system according to the space vector and zero sequence component.

15. The device for analyzing according to claim 14 , wherein the at least one energy parameter includes at least one of:
a total rms current or voltage value,
a total three-phase active power,
a total three-phase apparent power, and
a total three-phase reactive power.

16. The device for analyzing according to claim 10 , wherein the processing circuitry is further configured to display a shape covered by the space vector in the complex plane.

17. A non-transitory recording medium including computer executable instructions, wherein the instructions, when executed by a computer, cause the computer to perform a method for analyzing quality of electrical energy in a three-phase electric power system to determine absence or presence of disturbance in the three-phase electric power system, the method comprising:
measuring a set of electrical quantities, the set including one electrical quantity per phase;
generating a space vector, which is a time-dependent complex number, from an instantaneous three-dimensional transformation of the set of measured electrical quantities, the space vector being generated over a sliding window; and
determining, according to the generated space vector, a set including at least one parameter representative of the quality of the electrical energy in the three-phase electric power system to determine the absence or the presence of disturbance in the three-phase electric power system, the at least one parameter including a parameter representative of voltage flicker.

Assignees

• Schneider Electric Ind Sas

Inventors

• Leprettre Benoit
• Craciun Octavian
• Bacha Seddik
• Granjon Pierre
• Radu Daniel

Classifications

• G01R23/20

  Measurement of non-linear distortion · CPC title

• G01R21/06 Primary

  by measuring current and voltage (G01R21/08 - G01R21/133 take precedence) · CPC title

• G01R11/19

  Compensating for errors caused by disturbing torque, e.g. rotating-field errors of polyphase meters · CPC title

• G01R29/16

  Measuring asymmetry of polyphase networks · CPC title

• G01R19/25 Primary

  using digital measurement techniques · CPC title