Partial discharge synthesizer

Patent metadata

Field	Value
Publication number	US-11181570-B2
Application number	US-201816232194-A
Country	US
Kind code	B2
Filing date	Dec 26, 2018
Priority date	Jun 15, 2018
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

An apparatus for generating electrical discharge includes a component that generates an electrical discharge, a measurement circuit configured to measure a magnitude of the electrical discharge, and a controller configured to control the magnitudes of the electrical discharge. A method for controlling a reference partial discharge signal in an electric power system includes generating a partial discharge for built in self test, controlling an expected discharge magnitude of the partial discharge, and includes measuring an actual discharge magnitude of the partial discharge.

First claim

What is claimed is:

1. An apparatus for generating electrical discharge, comprising:
a component that generates an electrical discharge;
a measurement circuit configured to measure a magnitude of the electrical discharge;
a controller configured to control the magnitudes of the electrical discharge;
a first current mirror having an input coupled to a discharge path of the component that generates the electrical discharge; and
a sensor, the sensor coupled to an output path of the first current mirror, the sensor sensing a magnitude of the electrical discharge.

2. The apparatus of claim 1 , wherein the controller is further configured to correct a magnitude of a subsequent discharge based on a measured magnitude of at least one previous discharge.

3. The apparatus of claim 1 , wherein the component that generates an electrical discharge is a gas discharge tube.

4. The apparatus of claim 3 , and further comprising a switched inductance, wherein the electrical discharge is generated by the switched inductance applying a voltage impulse to the gas discharge tube.

5. The apparatus of claim 4 , and further comprising a resistance element coupled in series between the switched inductance and the gas discharge tube, wherein the magnitude of the electrical discharge is controlled by adjusting a resistance of the resistance element.

6. The apparatus of claim 4 , and further comprising a shunt capacitance element coupled in parallel with the gas discharge tube, wherein the magnitude of the discharge is controlled by adjusting a capacitance of the shunt capacitance element.

7. The apparatus of claim 4 , and further comprising a capacitance element coupled in series with the gas discharge tube, wherein the magnitude of the discharge is controlled by adjusting a capacitance of the capacitance element.

8. The apparatus of claim 3 , and further comprising:
a stepped DC voltage source; and
a resistance element coupled in series between the stepped DC voltage source and the gas discharge tube;
wherein the controller is further configured to generate the discharge by applying the stepped DC voltage through the resistance element to the gas discharge tube.

9. The apparatus of claim 8 , wherein the controller is further configured to control the magnitude of the discharge by varying the stepped DC voltage.

10. The apparatus of claim 8 , wherein the magnitude of the discharge is controlled by adjusting a resistance of the resistance element.

11. The apparatus of claim 8 , and further comprising a shunt capacitance element coupled in parallel with the gas discharge tube, wherein the magnitude of the discharge is controlled by adjusting a capacitance of the shunt capacitance element.

12. The apparatus of claim 8 , and further comprising a capacitance element coupled in series with the gas discharge tube, wherein the magnitude of the discharge is controlled by adjusting a capacitance of the capacitance element.

13. The apparatus of claim 1 , wherein the measurement circuit comprises a sense resistor in a discharge path of the electrical discharge.

14. The apparatus of claim 1 , wherein the measurement circuit comprises a Hall sensor in a discharge path of the electrical discharge.

15. The apparatus of claim 1 , wherein the measurement circuit comprises a sense resistor coupled to the discharge path.

16. The apparatus of claim 1 , wherein the measurement circuit comprises a Hall sensor measuring electrical discharge in the discharge path.

17. The apparatus of claim 1 , wherein the measurement circuit comprises an integrating capacitance in a discharge path of the electrical discharge.

18. The apparatus of claim 1 , and further comprising:
a second current mirror having an input coupled to a reference capacitance matching a capacitance of the component that generates the electrical discharge; and
a reference sensor, the reference sensor coupled to an output path of the second current mirror, the reference sensor sensing a magnitude of the electrical current in said reference capacitor without electrical discharge; and
a meter coupled to said sensor and said reference sensor, the meter generating a difference between a magnitude at the output path of the first current mirror and the output path of the second current mirror.

19. A system, comprising:
an electric power system comprising a partial discharge measurement component; and
a component that generates an electrical discharge;
a measurement circuit configured to measure a magnitude of the electrical discharge;
a controller configured to control the magnitude of the electrical discharge;

wherein the controller is further configured to perform a built-in self-test calibration process of measurement instruments integral to the system by:
sequentially instructing the system to perform a self-test of the system and its measurement instruments by generating and internally measuring an electrical discharge at a predetermined level in a predetermined pattern;
internally measuring a response to the self-test electrical discharge with the measurement circuit;
externally measuring a system response to the internally measured discharge;

determining a calibration state of the measurement circuit; and
using the calibration state to adjust the measurement circuit.

20. A method for controlling a reference partial discharge signal in an electric power system using a component that generates an electrical discharge, a measurement circuit configured to measure a magnitude of the electrical discharge, and a controller configured to control the magnitudes of the electrical discharge, the method, comprising:
generating a partial discharge for built in self test;
controlling an expected discharge magnitude of the partial discharge; and
measuring an actual discharge magnitude of the partial discharge.

21. The method of claim 20 , and further comprising adjusting the actual discharge magnitude by adjusting the expected discharge magnitude in response to measured actual discharge magnitude.

22. The method of claim 20 , and further comprising correcting a magnitude of a subsequent discharge based on a measured magnitude of one or more previous discharges.

23. The method of claim 20 , wherein generating a partial discharge comprises generating with a gas discharge tube.

24. The method of claim 23 , wherein controlling the expected discharge magnitude comprises generating the partial discharge with a switched inductance applying a pulse to the gas discharge tube.

25. The method of claim 24 , wherein controlling an expected discharge magnitude comprises adjusting a resistance of a resistance element coupled in series between the switched inductance and the gas discharge tube.

26. The method of claim 23 , wherein controlling the expected discharge magnitude comprises coupling a shunt capacitance element in parallel with the gas discharge tube and adjusting a capacitance of the shunt capacitance element.

27. The method of claim 23 , wherein controlling an expected discharge magnitude comprises coupling a capacitance element in series with the gas discharge tube and controlling the magnitude of the discharge by adjusting a capacitance of the capacitance element.

28. The method of claim 23 , wherein controlling the expected discharge magnitude comprises:
providing a stepped DC voltage source;
providing a resistance element coupled

Assignees

• Rosemount Inc

Inventors

• Andle Jeffrey C
• Lane David
• Chap Maly

Classifications

• G01R31/12 Primary

  Testing dielectric strength or breakdown voltage {; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing (G01R31/08, G01R31/327 and G01R31/72 take precedence; measuring in plasmas G01R19/0061; measuring dielectric constants G01R27/2617; ESD, EMC or EMP testing of circuits G01R31/002)} · CPC title

• G01R31/1227

  of components, parts or materials (G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16) · CPC title

• G01R31/245

  Testing of gas discharge tubes · CPC title

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01R31/1272

  of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083) · CPC title