Method for diagnosing internal fault of oil-immersed transformer through content ratios of dissolved gases

Patent metadata

Field	Value
Publication number	US-9535134-B2
Application number	US-201214368476-A
Country	US
Kind code	B2
Filing date	Dec 26, 2012
Priority date	Dec 26, 2011
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A method for accurately diagnosing an internal fault of an oil-immersed transformer by analyzing content ratios of dissolved gases generated when the internal fault occurs in the oil-immersed transformer is provided. The method diagnoses the internal fault by analyzing the dissolved gases contained in the insulating oil of the oil-immersed transformer for internal fault diagnosis, wherein the method comprises: a first step of extracting H2, CH4, C2H4, and C2H2 from the dissolved gases; a second step of calculating a content ratio (%) of each dissolved gas from the total content of the four dissolved gases selected from the extracted five dissolved gases; and a third step of determining the internal fault of the oil-immersed transformer for diagnosis corresponding to an internal fault region according to content ratio (%) values of the calculated four dissolved gases and predetermined content ratios (%) of the four dissolved gases.

First claim

The invention claimed is:

1. A method of diagnosing an internal fault of an oil-immersed transformer through a combination of content ratios of dissolved gases, which is capable of analyzing the dissolved gases contained in the insulation oil of the oil-immersed transformer of which the internal fault is able to be diagnosed, the method comprising:
a first step of extracting H2, CH4, C2H2, C2H4, and C2H6 from the dissolved gases;
a second step of selecting four dissolved gases, classified depending on each internal fault, from the five extracted and dissolved gases, so as to calculate a content ratio of each dissolved gas to a total content of the four selected and dissolved gases; and
a third step of determining a type of the internal fault of the immersed transformer for the diagnosis by enabling one to four combinations, which are selected from combinations of % H2 and % CH4, % H2 and % C2H2, % C2H4 and % C2H2, % C2H4 and % CH4, % H2 and % C2H6, and % C2H4 and % C2H6 which are calculated, to correspond to a predetermined internal fault region.

2. The method as claimed in claim 1 , wherein the third step comprises:
setting values of the content ratio of % H2 and % CH4 of each oil-immersed transformer, of which a type of the internal faults is known, depending on each of a partial discharge PD, a low energy discharge D1, a high energy discharge D2, a first thermal fault (t<300° C.) T1, a second thermal fault (300° C.<t<700° C.), and a third thermal fault (t>700° C.) T3; and
classifying half a region of the first xy-plane into a partial discharge (PD) fault region, a low energy discharge (D1) fault region, a high energy discharge (D2) fault region, a first thermal fault (t<300° C.) (T1) region, a second thermal fault (300° C.<t<700° C.) (T2) region, and a thermal fault (t>700° C.) region by using the plurality of set coordinates,
wherein the internal fault of the oil-immersed transformer for the diagnosis is determined by using a region corresponding to x and y coordinates for the values of % H2 and % CH4 calculated in the second step.

3. The method as claimed in claim 2 , wherein the values of % H2-% CH4, % H2-% C2H2, % C2H4-% C2H2, and % C2H4-% CH4 are in a range of 0˜100% on each x-y axis on the first to fourth xy-plane, and the fault region is located within a triangular shape defined by connecting points, at which the x axis and the y axis are 100%.

4. The method as claimed in claim 3 , wherein the content ratio of each dissolved gas, which is calculated in the second step, is included in the fault region within the triangular shape.

5. The method as claimed in claim 1 , wherein the third step comprises:
setting of the values of % H2 and % C2H2, which are content ratios indicated depending on each of a partial discharge (PD), a low energy discharge (D1), and a high energy discharge (D2) of a thermal fault and an electrical fault, as x and y coordinates for each of a plurality of oil-immersed transformers, of which a type of the internal fault is known, on a second xy-plane; and
classifying half a region of the second xy-plane into the partial discharge (PD) fault region, a low energy discharge (D1) fault region, and a high energy discharge (D2) fault region of a thermal fault region and an electrical region,
wherein the internal fault of the oil-immersed transformer used for diagnosis is determined by using a region corresponding to x and y coordinates for the values of % H2 and % C2H2 calculated in the second step.

6. The method as claimed in claim 5 , wherein the values of % H2-% CH4, % H2-% C2H2, % C2H4-% C2H2, and % C2H4-% CH4 are in a range of 0˜100% on each x-y axis on the first to fourth xy-plane, and the fault region is located within a triangular shape defined by connecting points, at which the x axis and the y axis are 100%.

7. The method as claimed in claim 1 , wherein the third step comprises:
setting values of the content ratio of % C2H4 and % C2H2 of each oil-immersed transformer, of which a type of the internal fault is known, depending on each of a partial discharge PD, a low energy discharge D1, a high energy discharge D2, a first thermal fault (t<300° C.) T1, a second thermal fault (300° C.<t<700° C.) T2, and a third thermal fault (t>700° C.) T3, as x and y coordinates on a third xy-plane; and
classifying half a region of the first xy-plane into a partial discharge (PD) fault region, a low energy discharge (D1) fault region, a high energy discharge (D2) fault region, a first thermal fault (t<300° C.) (T1) region, a second thermal fault (300° C.<t<700° C.) (T2) region, and a thermal fault (t>700° C.) region by using the plurality of set coordinates,
wherein the internal fault of the oil-immersed transformer for the diagnosis is determined by using a region corresponding to x and y coordinates for the values of % C2H4 and % C2H2 calculated in the second step.

8. The method as claimed in claim 7 , wherein the values of % H2-% CH4, % H2-% C2H2, % C2H4-% C2H2, and % C2H4-% CH4 are in a range of 0˜100% on each x-y axis on the first to fourth xy-plane, and the fault region is located within a triangular shape defined by connecting points, at which the x axis and the y axis are 100%.

9. The method as claimed in claim 1 , wherein the third step comprises:
setting values of the content ratio of % C2H4 and % CH4 of each oil-immersed transformer, of which a type of the internal faults is known, depending on each of a partial discharge PD, a low energy discharge D1, a high energy discharge D2, a first thermal fault (t<300° C.) T1, a second thermal fault (300° C.<t<700° C.) T2, and a third thermal fault (t>700° C.) T3, as x and y coordinates on a four X-Y plane; and
classifying half a region of the fourth xy-plane into a partial discharge (PD) fault region, a low energy discharge (D1) fault region, a high energy discharge (D2) fault region, a first thermal fault (t<300° C.) (T1) region, a second thermal fault (300° C.<t<700° C.) (T2) region, and a thermal fault (t>700° C.) (T3) region by using the plurality of set coordinates,
wherein the internal fault of the oil-immersed transformer for the diagnosis is determined by using a region corresponding to x and y coordinates for the values of % C2H4 and % CH4 calculated in the second step.

10. The method as claimed in claim 9 , wherein the values of % H2-% CH4, % H2-% C2H2, % C2H4-% C2H2, and % C2H4-% CH4 are in a range of 0˜100% on each x-y axis on the first to fourth xy-plane, and the fault region is located within a triangular shape defined by connecting points, at which the x axis and the y axis are 100%.

11. A method of diagnosing an internal fault of an oil-immersed transformer through a combination of content ratios of dissolved gases, the method comprising:
a first step of extracting the dissolved gases of H2, CH4, C2H2, C2H4, and C2H6 from each oil-immersed transformer of which a type of the internal faults is known;
a second step of selecting four dissolved gases, classified depending on each internal fault, from the five extracted and dissolved gases, so as to calculate a content ratio of each dissolved gas to a total content of the four selected and dissolved gases;
a third step of classifying half a region of the first xy-plane into the internal fault region by using the plurality of the first x and y coordinates after setting the values of % H2 and % CH4, which are content ratios indicated by each internal fault, as the first x and y coordinates respectively on the first xy-plane;
a fourth step of classifying half a region of the second xy-plane into the internal fault region by using the plurality of the second x and y coordinates after setting the values of % H2 and % C2H2, which are content ratios indicated by each in

Assignees

• Hyosung Corp

Inventors

• Kim Young-Min
• Kim Sung-Jik
• Seo Hwang-Dong
• Lee Soo-Jin

Classifications

• G01R31/62

  Testing of transformers · CPC title

• H01F27/12

  Oil cooling · CPC title

• G01N33/0004

  Gaseous mixtures, e.g. polluted air · CPC title

• G01F1/72

  Devices for measuring pulsing fluid flows · CPC title

• H01F27/402

  Association of measuring or protective means · CPC title