Process for identifying abnormalities in power transformers
First Claim
1. A method for identifying a type of abnormality in an insulation system of a power transformer, comprising:
- measuring dielectric losses in a section of the insulation system;
calculating theoretical dielectric losses for the section based on the material properties, geometry, and temperature of the section;
generating a graphical representation of a percent difference between the measured and calculated dielectric losses; and
comparing a shape of the graphical representation with a shape of one or more graphical representations of a percent difference between measured and theoretical dielectric losses in one or more other sections of insulation each known to have a specific type of abnormality.
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Accused Products
Abstract
A preferred method for identifying a type of abnormality in an insulation system of a power transformer comprises measuring dielectric losses in a section of the insulation system, calculating theoretical dielectric losses for the section based on the material properties, geometry, and temperature of the section, and generating a graphical representation of a percent difference between the measured and calculated dielectric losses. The preferred method also comprises comparing a shape of the graphical representation with a shape of one or more graphical representations of a percent difference between measured and theoretical dielectric losses in one or more other sections of insulation each known to have a specific type of abnormality.
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Citations
26 Claims
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1. A method for identifying a type of abnormality in an insulation system of a power transformer, comprising:
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measuring dielectric losses in a section of the insulation system;
calculating theoretical dielectric losses for the section based on the material properties, geometry, and temperature of the section;
generating a graphical representation of a percent difference between the measured and calculated dielectric losses; and
comparing a shape of the graphical representation with a shape of one or more graphical representations of a percent difference between measured and theoretical dielectric losses in one or more other sections of insulation each known to have a specific type of abnormality. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method, comprising:
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measuring a dielectric frequency response of a section of insulation within a power transformer;
calculating a theoretical dielectric frequency response for the section;
generating a dielectric frequency response signature for the section; and
comparing the dielectric frequency response signature to the dielectric frequency response signature of other sections of the insulation known to have particular types of abnormalities. - View Dependent Claims (14, 15)
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16. A method for classifying a type of abnormality in a section of insulation in a power transformer, comprising:
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energizing a conductor insulated by the section of insulation with an alternating-current voltage;
varying a frequency of the alternating-current voltage between a plurality of discrete frequencies within a predetermined range;
measuring the dielectric loss in the section of insulation at each of the discrete frequencies;
calculating a theoretical dielectric loss for the section of insulation at each of the discrete frequencies;
calculating a percent difference between the measured dielectric loss and the theoretical dielectric loss at each of the discrete frequencies;
generating a substantially curvilinear representation of the percent differences between the measured dielectric loss and the calculated dielectric loss at each of the discrete frequencies; and
comparing a shape of the substantially curvilinear representation to a shape of one or more predetermined curvilinear representations of a percent difference between a measured dielectric loss and a calculated dielectric loss for a section of insulation known to have a particular type of abnormality. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A method, comprising:
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measuring a dielectric loss in a section of an insulation system of a power transformer in response to an alternating-current voltage varied over a predetermined range of frequencies;
calculating a theoretical dielectric loss for the section based on the material properties, geometry, and temperature of the section of insulation;
generating a representation of a percent difference between the measured and calculated dielectric losses; and
determining whether a shape of the representation substantially differs from a representation of a percent difference between measured and calculated dielectric losses in another section of the insulation previously identified as having a specific type of abnormality.
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24. A method for identifying a type of abnormality in an insulation system of a power transformer, comprising:
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measuring dielectric losses in a section of the insulation system;
calculating theoretical dielectric losses for the section;
identifying the section as having an abnormality by comparing the measured dielectric losses in the section to the theoretical dielectric losses for the section;
generating a graphical representation of a percent difference between the measured and calculated dielectric losses; and
comparing a shape of the graphical representation with a shape of one or more graphical representations of a percent difference between measured and theoretical dielectric losses in one or more other sections of the insulation each known to have a specific type of abnormality. - View Dependent Claims (25)
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26. A method, comprising:
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measuring a dielectric frequency response of a section of insulation within a power transformer;
calculating a theoretical dielectric frequency response for the section;
identifying the section as having an abnormality therein by comparing the measured dielectric response and the theoretical dielectric response;
generating a dielectric frequency response signature for the section; and
comparing the dielectric frequency response signature to a dielectric frequency response signature of other sections of the insulation known to have particular types of abnormalities.
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Specification