Temperature compensation of insulation monitoring for rotating machines

Patent metadata

Field	Value
Publication number	US-10539601-B2
Application number	US-201715714788-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Nov 6, 2013
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A system includes a monitoring and/or protection system that includes an insulation derivation circuit. The insulation derivation circuit is configured to derive a first temperature compensation curve based on a first temperature and a first current, and the monitoring and/or protection system is configured to communicatively couple to a first current sensor configured to sense the first current traversing a first phase of a stator winding of a motor, a generator, or a combination thereof. The insulation derivation circuit is also configured to communicatively couple to a first temperature sensor configured to sense the first temperature of the stator when the stator is energized, and the temperature compensation curve is configured to map a temperature to a leakage dissipation factor.

First claim

The invention claimed is:

1. A non-transitory computer readable medium comprising instructions configured to:
derive, via a monitoring and/or protection system comprising an insulation derivation circuit, an original current measurement based on a signal from a current sensor sensing a current traversing a stator winding of a motor, a generator, or a combination thereof by comparing a phase of the current sensed by the current sensor with a phase of a voltage associated with the current and sensed via a line voltage sensor;
derive, via the monitoring and/or protection system, an original temperature measurement based on a temperature signal from a temperature sensor disposed in a stator comprising the stator winding and configured to sense a temperature when the stator is energized; and
derive, via the monitoring and/or protection system, an original insulation condition based on the original current measurement and the original temperature measurement.

2. The non-transitory computer readable medium of claim 1 , wherein the instructions are configured to:
derive a present current measurement based on a second signal from the current sensor sensing a current traversing the stator winding of the motor, the generator, or the combination thereof;
derive a present temperature measurement based on a second temperature signal from the temperature sensor; and
derive a present insulation condition based on the present current measurement and the present temperature measurement; and
compare the present insulation condition to the original insulation condition to determine a degradation factor.

3. The non-transitory computer readable medium of claim 2 , wherein comparing the present insulation condition to the original insulation condition includes using a temperature compensation curve.

4. The non-transitory computer readable medium of claim 1 , wherein the instructions are configured to derive the original insulation condition using a neural network, a genetic algorithm, an expert system, or a combination thereof.

5. The non-transitory computer readable medium of claim 1 , wherein the instructions are configured to derive the original insulation condition using a polynomial function fit curve wherein the function is fit to a curve on a graph with a dissipation factor as an ordinate and a temperature as an abscissa.

6. The non-transitory computer readable medium of claim 1 , wherein the instructions are embodied on a rack-mountable card.

7. The non-transitory computer readable medium of claim 1 , wherein the instructions are configured to transfer the original insulation condition to an external storage location.

8. A method, comprising:
deriving, via a monitoring and/or protection system comprising an insulation derivation circuit, an original current measurement based on a signal from a current sensor sensing a current traversing a stator winding of a motor, a generator, or a combination thereof by comparing a phase of the current sensed by the current sensor with a phase of a voltage associated with the current and sensed via a line voltage sensor;
deriving, via the monitoring and/or protection system, an original temperature measurement based on a temperature signal from a temperature sensor disposed in a stator comprising the stator winding and configured to sense a temperature when the stator is energized; and
deriving, via the monitoring and/or protection system, an original insulation condition based on the original current measurement and the original temperature measurement.

9. The method of claim 8 , comprising:
deriving a present current measurement based on a second signal from the current sensor sensing a current traversing of the stator winding of the motor, the generator, or the combination thereof;
deriving a present temperature measurement based on a second temperature signal from the temperature sensor; and
deriving a present insulation condition based on the present current measurement and the present temperature measurement; and
comparing the present insulation condition to the original insulation condition to determine a degradation factor.

10. The method of claim 8 , wherein deriving an original current measurement, deriving an original temperature measurement, or any combination thereof comprises deriving for a learning period, wherein the learning period begins at a startup of the motor, the generator, or combination thereof within the stator, and ends after a user-defined time period.

11. A system, comprising:
a current sensor configured to sense a current traversing a stator winding of a motor, a generator, or a combination thereof;
a temperature sensor disposed in a stator comprising the stator winding and configured to sense a temperature when the stator is energized; and
an insulation derivation circuit comprising a processor communicatively coupled to the current sensor and the temperature sensor, and wherein the processor is configured to:
derive an original current measurement based on a signal from the current sensor by comparing a phase of the current sensed by the current sensor with a phase of a voltage associated with the current and sensed via a line voltage sensor;
derive an original temperature measurement based on a temperature signal from the temperature sensor; and
derive an original insulation condition of an insulation of the stator winding based on the original current measurement and the original temperature measurement.

12. The system of claim 11 , wherein the processor is configured to:
derive a present current measurement based on a second signal from the current sensor sensing a current traversing the first phase of the stator winding of the motor, the generator, or the combination thereof;
derive a present temperature measurement based on a second temperature signal from the temperature sensor; and
derive a present insulation condition for the insulation of the first phase of the stator winding based on the present current measurement and the present temperature measurement; and
compare the present insulation condition to the original insulation condition to determine a degradation factor for the insulation of the first phase of the stator winding.

13. The system of claim 12 , wherein the processor is configured to compare the present insulation condition to the original insulation condition using a temperature compensation curve.

14. The system of claim 11 , wherein the processor is configured to derive the original insulation condition using a neural network, a genetic algorithm, an expert system, or a combination thereof.

15. The system of claim 11 , wherein the processor is configured to derive the original insulation condition using a polynomial function fit curve wherein the function is fit to a curve on a graph with a dissipation factor as an ordinate and a temperature as an abscissa.

16. The system of claim 11 , wherein the insulation derivation circuit is configured to transfer the original insulation condition derived by the processor to an external storage location.

17. The system of claim 11 , comprising:
a second current sensor configured to sense a second current traversing a second stator winding of the motor, the generator, or the combination thereof and generate a second signal based upon the sensed second current; and
a second temperature sensor disposed in the stator comprising the second stator winding and configured to sense a second temperature when the stator is energized and generate a second temperature signal based upon the sensed second temperature, wherein the processor of the ins

Assignees

• Gen Electric

Inventors

• Lu Dan Tho
• Wilson Ronald W

Classifications

• G01R31/346

  Testing of armature or field windings · CPC title

• G01R19/32

  Compensating for temperature change · CPC title

• G01R35/00

  Testing or calibrating of apparatus covered by the other groups of this subclass · CPC title

• G01R31/024 Primary

  Physics · mapped topic

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title