Fault Detection Method and System Based on Dissolved Gases in Modified Ester Insulating Oil

Abstract

This invention discloses a fault diagnosis method and system based on dissolved gases in modified ester insulating oil. The method includes the following steps: S1, constructing a gas generation simulation system for overheating defects in modified ester paper insulation; S2, using the simulation system to simulate different types of overheating defects in paper insulation, performing DGA analysis, and collecting data on different types of overheating defects in modified ester paper insulation; S3, based on the DGA analysis data, finding boundary values ​​that distinguish different overheating defects, deriving a coding rule table and an overheating defect type judgment table based on the boundary values, and performing fault diagnosis based on the overheating defect type judgment table. This invention can achieve criterion correction for different types of modified esters, provide judgment intervals based on the characteristics of modified esters according to existing data, and improve the judgment accuracy of the three-ratio method for dissolved gas analysis in modified ester oil.

Description

Technical Field

[0001] This invention belongs to the field of power equipment fault diagnosis technology, specifically relating to a fault identification method and system based on dissolved gases in modified ester insulating oil. Background Technology

[0002] Currently available characteristic gas methods for various types of natural and synthetic ester insulating liquids include the IEC three-ratio method. The three-ratio method, as given in IEC 60599-2015, uses five gases selected from dissolved gases in mineral oil to form three ratios: C2H2 / C2H4, CH4 / H2, and C2H4 / C2H6. The fault type of the insulating liquid is determined by classifying the proportions of these three gases. If this method is directly applied to natural, synthetic, and modified ester insulating liquids, the IEC three-ratio method based on mineral oil may still be applicable to low-temperature thermal fault determination. However, for medium- and high-temperature thermal fault determination, substituting the dissolved gas values ​​from the thermal fault simulation into the IEC three-ratio method results in errors. This indicates that the three-ratio method has errors in determining thermal faults across the entire temperature range. Summary of the Invention

[0003] The main objective of this invention is to overcome the shortcomings and deficiencies of the prior art and propose a fault discrimination method and system based on dissolved gases in modified ester insulating oil. This method can correct the criteria for different types of modified esters, provide a judgment range based on the characteristics of modified esters according to existing data, and improve the judgment accuracy of the three-ratio method for dissolved gas analysis in modified ester oil.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The fault detection method based on dissolved gases in modified ester insulating oil includes the following steps:

[0006] S1. Construct a simulation system for gas generation due to overheating defects in modified ester-oil paper insulation;

[0007] S2. Simulation system is used to simulate different types of overheating defects in oil-paper insulation, DGA analysis is performed, and data on overheating defects of different types of modified ester oil-paper insulation are collected.

[0008] S3. Based on the DGA analysis data, find the boundary values ​​that distinguish different overheating defects. Based on the boundary values, derive the coding rule table and the overheating defect type judgment table. Based on the overheating defect type judgment table, perform fault identification.

[0009] Furthermore, in step S1, the modified ester paper insulation overheating defect gas generation simulation system includes a high-current heating module, a temperature monitoring module, a gas collection module, and a modified ester circulation module.

[0010] The high-current heating module is connected to the temperature monitoring module.

[0011] Furthermore, the high-current heating module, a large-area energized metal, is used to provide a heat source inside the modified ester oil paper insulation of the transformer winding coil, simulating the heating of the winding inside the transformer.

[0012] The temperature monitoring module uses a thermocouple inside the modified ester-oil paper insulation to monitor the temperature of the high-current heating module;

[0013] Gas collection module is used to collect gases generated by overheating defects in different types of oil-paper insulation.

[0014] The modified ester circulation module is used to provide the flow power inside the modified ester oil-paper insulation system, accelerating the heat exchange and gas dissolution within the system.

[0015] Furthermore, different types of overheating defects in oil-paper insulation specifically include low-temperature thermal failures, medium-temperature thermal failures, and high-temperature thermal failures.

[0016] Among them, the temperature range corresponding to low-temperature thermal failure is 150 to 300℃;

[0017] The temperature range corresponding to medium-temperature thermal failures is 300 to 700℃.

[0018] The temperature range corresponding to high-temperature thermal failure is greater than 700℃.

[0019] Furthermore, the high-current heating module provides an adjustable current range of 0-1000A, with a conductor current density of 2-4A / mm². 2 .

[0020] Furthermore, the temperature monitoring module has a detection range of at least 150 to 800°C.

[0021] Furthermore, after constructing different types of overheating defects in oil-paper insulation, the gas generation simulation system monitors whether gas is generated under different types of overheating defects through a gas collection module.

[0022] Insulating oil from different types of overheating defects in oil-paper insulation was extracted. Gas chromatography was used to analyze the types and contents of dissolved gases in the oil caused by local overheating of the oil-paper insulation winding, identify the gas generation patterns under different types of insulation overheating defects, and store the data in the DGA database.

[0023] Furthermore, step S2 specifically adjusts the winding current by regulating the high-current heating module of the gas generation simulation system, and monitors the temperature information inside the oil-paper insulation system through the temperature monitoring module to simulate different types of overheating defects in oil-paper insulation.

[0024] Further, step S3 specifically includes:

[0025] S31. Obtain the C2H4 / C2H6 ratio sequences {X1…X n} under T1 low-temperature faults and the C2H4 / C2H6 ratio sequences {Y1…Y m} under T2 medium-temperature faults in the modified ester insulating oil DGA database;

[0026] S32. Set the C2H4 / C2H6 ratio for distinguishing T1 and T2 temperature faults as S. That is, when the C2H4 / C2H6 ratio is less than S, it is determined as T1, and when it is greater than S, it is determined as T2;

[0027] S33. Initially set 0 < S ≤ 2 and step = 0.1. Use S = S + step and loop through all possible values of S;

[0028] S34. According to the S value set in step S33, perform temperature fault discrimination on the sequences {X1…X n} and {Y1…Y m} to obtain the positive discrimination rates of faults in the T1 and T2 intervals as T1% and T2%;

[0029] S35. Loop steps S33 to S34. When the values of T1% and T2% are both greater than 70%, and the S value that makes the value of T1% + T2% the largest is the boundary value for distinguishing the T1 and T2 intervals;

[0030] S36. According to the boundary value for distinguishing low-temperature faults and medium-temperature faults, organize and obtain a complete coding rule table and a fault type judgment table, and perform fault discrimination according to the fault type judgment table.

[0031] The present invention also includes a fault discrimination system based on dissolved gases in modified ester insulating oil, including a large current heating module, a temperature monitoring module, a gas collection module, a modified ester circulation module, and a temperature fault discrimination module;

[0032] The large current heating module, the temperature monitoring module, the gas collection module, and the modified ester circulation module constitute a modified ester oil-paper insulation overheating defect gas generation simulation system. The large current heating module is connected to the temperature monitoring module and transmits the collected data to the temperature fault discrimination module. The temperature fault discrimination module performs fault discrimination according to the transmitted data using the fault discrimination method provided by the present invention.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. This invention proposes a fault identification method based on dissolved gases in modified ester insulating oil. This method can correct the overheating fault identification method for different types of modified esters produced by different manufacturers and combined with insulating paper, and obtain accurate fault identification boundary values ​​and specific coding tables.

[0035] 2. The present invention includes a gas generation simulation system for overheating defects in modified ester-oil paper insulation. This system can simulate overheating faults in an oil-paper insulation system composed of modified ester insulating oil and cellulose paper by heating the conductor with a large current. After simulating the thermal fault, the dissolved gas value in the insulating liquid can be substituted into the fault discrimination method of the present invention for correction, thereby obtaining a more accurate overheating fault discrimination method.

[0036] 3. The existing IEC three-ratio method is designed for the dissolved gas characteristics in mineral oil faults and needs to be revised for ester-based insulating liquids. Current research mainly focuses on natural esters and synthetic esters, while research on modified esters is relatively limited. The fault identification method and system of this invention fills the gap in this field. Attached Figure Description

[0037] Figure 1 This is a flowchart of the method of the present invention;

[0038] Figure 2 This is a structural diagram of a system for simulating gas generation due to overheating defects in modified ester-coated paper insulation. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0040] Example

[0041] like Figure 1 As shown, the present invention provides a fault detection method based on dissolved gases in modified ester insulating oil, comprising the following steps:

[0042] S1. Construct a simulation system for gas generation due to overheating defects in modified ester-coated paper insulation; such as... Figure 2 As shown, the modified ester insulating oil overheating defect gas generation simulation system includes a high-current heating module, a temperature monitoring module, a gas collection module, and a modified ester circulation module; the high-current heating module is connected to the temperature monitoring module.

[0043] The high-current heating module is a large-area energized metal used to provide a heat source within the modified ester-oil paper insulation structure of a transformer winding, simulating the heating of the transformer windings. The provided current is adjustable within the range of 0-1000A, and the conductor current density is 2-4A / mm². 2 .

[0044] The temperature monitoring module uses thermocouples inside the modified ester-oil paper insulation to monitor the temperature of the high-current heating module. The temperature monitoring module has a detection range of at least 150 to 800°C.

[0045] Gas collection module is used to collect gases generated by overheating defects in different types of oil-paper insulation.

[0046] The modified ester circulation module is used to provide the flow power inside the modified ester oil-paper insulation system, accelerating the heat exchange and gas dissolution within the system.

[0047] Different types of overheating defects in oil-paper insulation specifically include low-temperature thermal failures, medium-temperature thermal failures, and high-temperature thermal failures.

[0048] Among them, the temperature range corresponding to low-temperature thermal failure is 150 to 300℃;

[0049] The temperature range corresponding to medium-temperature thermal failures is 300 to 700℃.

[0050] The temperature range corresponding to high-temperature thermal failure is greater than 700℃.

[0051] In this embodiment, after constructing different types of overheating defects in oil-paper insulation, the gas generation simulation system monitors whether gas is generated under different types of defects through a gas collection module.

[0052] Insulating oil from different types of overheating defects in oil-paper insulation was extracted. Gas chromatography was used to analyze the types and contents of dissolved gases in the oil caused by local overheating of the oil-paper insulation winding, identify the gas generation patterns under different types of insulation overheating defects, and store the data in the DGA database.

[0053] S2. A gas generation simulation system is used to simulate different types of overheating defects in oil-paper insulation, and DGA analysis is performed to collect data on different types of overheating defects in modified ester oil-paper insulation. Specifically, the winding current is adjusted by regulating the high-current heating module of the gas generation simulation system, and the temperature information inside the oil-paper insulation system is monitored by the temperature monitoring module to simulate different types of overheating defects in oil-paper insulation.

[0054] S3. Based on DGA analysis data, identify boundary values ​​that distinguish different overheating defects. Based on these boundary values, derive a coding rule table and an overheating defect type judgment table. Then, use the overheating defect type judgment table to determine the fault. Specifically, this includes:

[0055] S31. Based on the C2H4 / C2H6 ratio sequence {X1…X1} under low-temperature fault T1 in the modified ester insulating oil DGA database. n} and the C2H4 / C2H6 ratio sequence {Y1…Y} under the T2 intermediate temperature fault. m};

[0056] S32. Set the C2H4 / C2H6 ratio for distinguishing T1 and T2 temperature faults as S. That is, when the C2H4 / C2H6 ratio is less than S, it is determined as T1, and when it is greater than S, it is determined as T2;

[0057] S33. Initially set 0 < S ≤ 2, step = 0.1, use S = S + step, and loop through all possible values of S;

[0058] S34. According to the S value set in step S33, perform temperature fault discrimination on the sequences {X1…X n} and {Y1…Y m}, and obtain the positive discrimination rates of faults in the T1 and T2 intervals as T1% and T2%;

[0059] S35. Loop steps S33 to S34. When the values of T1% and T2% are both greater than 70%, and the S value that makes the value of T1% + T2% the largest is the boundary value for distinguishing the T1 and T2 intervals;

[0060] S36. According to the boundary value for distinguishing low - temperature faults and medium - temperature faults, organize and obtain a complete coding rule table and a fault type judgment table, and perform fault discrimination according to the fault type judgment table.

[0061] In this embodiment, in the T1 interval, C2H4 / CH4 < 1; in the T2 interval, C2H4 / CH4 > 1, distinguish T1 and T2, and obtain a coding rule table and a fault type judgment table; the coding rule table is shown in Table 1 below, and the fault type judgment table is shown in Table 2 below.

[0062]

[0063]

[0064] Table 1

[0065]

[0066] Table 2

[0067] In another embodiment, a fault discrimination system based on dissolved gases in modified ester insulating oil is also provided. The system includes a large - current heating module, a temperature monitoring module, a gas collection module, a modified ester circulation module, and a temperature fault discrimination module;

[0068] The large - current heating module, the temperature monitoring module, the gas collection module, and the modified ester circulation module constitute a simulation system for generating gas due to overheating defects in modified ester oil - paper insulation. The large - current heating module is connected to the temperature monitoring module and transmits the collected data to the temperature fault discrimination module. The temperature fault discrimination module performs fault discrimination according to the transmitted data using the fault discrimination method described in the above - mentioned embodiment.

[0069] It should also be noted that, in this specification, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fault detection method based on dissolved gases in modified ester insulating oil, characterized in that, It includes the following steps: S1. Construct a gas generation simulation system for overheating defects of modified ester oil-paper insulation; S2. Use the simulation system to simulate different types of overheating defects of oil-paper insulation, conduct DGA analysis, and collect data on different types of overheating defects of modified ester oil-paper insulation; the different types of overheating defects of oil-paper insulation specifically include low-temperature thermal faults, medium-temperature thermal faults, and high-temperature thermal faults; Among them, the low-temperature thermal fault corresponds to a temperature range of 150 to 300 °C; The medium-temperature thermal fault corresponds to a temperature range of 300 to 700 °C; The high-temperature thermal fault corresponds to a temperature range greater than 700 °C; After constructing different types of overheating defects of oil-paper insulation, the gas generation simulation system monitors whether gas is generated under different types of overheating defects through the gas collection module; Extract the insulating oil of different types of overheating defects of oil-paper insulation, use gas chromatography analysis method to analyze the types and gas contents of dissolved gases in oil generated by local overheating of oil-paper insulation windings, identify the gas generation rules under different types of insulating overheating defects, and store the data in the DGA database; S3. According to the DGA analysis data, find the boundary values for distinguishing different overheating defects, obtain the coding rule table and overheating defect type judgment table based on the boundary values, and conduct fault discrimination according to the overheating defect type judgment table; specifically including: S31. Obtain the C2H4 / C2H6 ratio sequence {X1…X1} under low-temperature fault T1 from the modified ester insulating oil DGA database. n } and the C2H4 / C2H6 ratio sequence {Y1…Y} under the T2 intermediate temperature fault. m }; S32. Let the C2H4 / C2H6 ratio for distinguishing T1 and T2 temperature faults be S, that is, when the C2H4 / C2H6 ratio is less than S, it is determined as T1, and when it is greater than S, it is determined as T2; S33. Initially set 0 < S ≤ 2, step = 0.1, and use S = S + step to loop through all possible values of S; S34. Based on the S value set in step S33, process the sequence {X1…X...} n } and {Y1…Y m Temperature fault identification was performed, and the positive identification rates for faults in the T1 and T2 intervals were T1% and T2%, respectively. S35. Loop steps S33 to S34. When the values of T1% and T2% both exceed 70% and make the value of T1% + T2% the largest, the S is the boundary value for distinguishing the T1 and T2 intervals; S36. Based on the boundary values for distinguishing low-temperature faults and medium-temperature faults, organize and obtain the complete coding rule table and fault type judgment table, and conduct fault discrimination according to the fault type judgment table.

2. The fault diagnosis method based on dissolved gases in modified ester insulating oil according to claim 1, characterized in that, In step S1, the gas generation simulation system for overheating defects of modified ester oil-paper insulation includes a large current heating module, a temperature monitoring module, a gas collection module, and a modified ester circulation module; The large current heating module is connected to the temperature monitoring module.

3. The fault diagnosis method based on dissolved gases in modified ester insulating oil according to claim 2, characterized in that, The large current heating module is a large-area energized metal, used to simulate the winding cake of a transformer, provide a heat source inside the modified ester oil-paper insulation, and simulate the winding heating inside the transformer; The temperature monitoring module uses thermocouples to monitor the temperature of the large current heating module inside the modified ester oil-paper insulation; The gas collection module is used to collect the gases generated by different types of overheating defects of oil-paper insulation; The modified ester circulation module is used to provide the flow power inside the modified ester oil-paper insulation system, and accelerate the heat exchange and gas dissolution inside the modified ester oil-paper insulation system.

4. The fault diagnosis method based on dissolved gases in modified ester insulating oil according to claim 3, characterized in that, The high-current heating module provides an adjustable current range of 0-1000A, with a conductor current density of 2-4A / mm². 2 .

5. The fault diagnosis method based on dissolved gases in modified ester insulating oil according to claim 3, characterized in that, The detection range of the temperature monitoring module includes at least 150 to 800 °C.

6. The fault diagnosis method based on dissolved gases in modified ester insulating oil according to claim 3, characterized in that, Step S2 specifically adjusts the winding current by controlling the large current heating module of the gas generation simulation system, and monitors the temperature information inside the oil-paper insulation system through the temperature monitoring module to simulate different types of overheating defects of oil-paper insulation.

7. A fault detection system based on dissolved gases in modified ester insulating oil, characterized in that, It includes a high-current heating module, a temperature monitoring module, a gas collection module, a modified ester circulation module, and a temperature fault detection module; A high-current heating module, a temperature monitoring module, a gas collection module, and a modified ester circulation module constitute a gas generation simulation system for overheating defects in modified ester oil-paper insulation. The high-current heating module is connected to the temperature monitoring module and transmits the collected data to the temperature fault discrimination module. The temperature fault discrimination module performs fault discrimination based on the transmitted data using the fault discrimination method described in any one of claims 1-6.

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