A method and device for evaluating the life of oil-paper insulation

Abstract

The application discloses an oil-paper insulation life evaluation method and device, which can place the to-be-evaluated oil-paper into first insulation oil, heat the first insulation oil to a preset accelerated thermal aging temperature, and keep the temperature for a predefined duration to perform accelerated thermal aging treatment on the to-be-evaluated oil-paper; obtain the sample after the accelerated thermal aging treatment, and place the sample into second insulation oil; heat the second insulation oil to a preset withstand voltage test temperature; perform a withstand voltage test on the sample after the accelerated thermal aging treatment in the heated second insulation oil according to a preset initial voltage, voltage duration and voltage increasing gradient; when the sample after the accelerated thermal aging treatment is broken down during the withstand voltage test, determine the withstand voltage duration of the sample after the accelerated thermal aging treatment; and evaluate the insulation life of the to-be-evaluated oil-paper based on the withstand voltage duration of the sample after the accelerated thermal aging treatment. The application can effectively evaluate the insulation life of the oil-paper, thereby determining the reliability of the insulation performance of the oil-paper.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power, and in particular to an oil-paper insulation life evaluation method and device. BACKGROUND

[0002] With the development of electric power technology, the operation control technology of the power system is continuously improved.

[0003] In the power system, the current transformer is an important component device, which undertakes the functions of current conversion, power transmission and electrical isolation in the power grid, and its safe and stable operation is very important to the power system.

[0004] At present, the current transformer in the power system can be an oil-immersed current transformer. The primary side and secondary side windings of the oil-immersed current transformer can be located in the oil tank at the upper part of the oil-immersed current transformer and are covered by insulating oil; the main insulation composed of oil paper at the upper part of the oil-immersed current transformer is a T-shaped structure and is completely immersed in the insulating oil.

[0005] Specifically, during the operation of the oil-immersed current transformer, the insulation performance of the oil paper will irreversibly age under the combined action of factors such as electricity, heat, mechanics and environment, causing the mechanical strength or insulation performance of the insulation system to decrease, resulting in insulation failure. Therefore, the remaining insulation life of the oil paper is of great significance to the safe and stable operation of the power system.

[0006] However, the prior art cannot effectively evaluate the insulation life of the oil paper. SUMMARY

[0007] In view of the above problems, the present application provides an oil-paper insulation life evaluation method and device which overcomes the above problems or at least partially solves the above problems, and the technical solution is as follows:

[0008] An oil-paper insulation life evaluation method, comprising:

[0009] obtaining oil paper to be evaluated;

[0010] placing the oil paper to be evaluated into first insulating oil, heating the first insulating oil to a preset accelerated thermal aging temperature, and maintaining the temperature of the first insulating oil at the accelerated thermal aging temperature for a predefined temperature duration, to perform accelerated thermal aging treatment on the oil paper to be evaluated, and obtain a sample after accelerated thermal aging treatment;

[0011] placing the sample after accelerated thermal aging treatment into second insulating oil, and heating the second insulating oil to a preset withstand voltage test temperature;

[0012] performing a withstand voltage test on the sample after accelerated thermal aging treatment in the heated second insulating oil according to a preset initial voltage, a voltage duration and a voltage rising gradient;

[0013] determining the voltage-withstanding duration of the accelerated heat-aging processed sample when the accelerated heat-aging processed sample is broken down during the voltage-withstanding test;

[0014] based on the voltage-withstanding duration of the accelerated heat-aging processed sample, evaluating the insulation life of the oil paper to be evaluated.

[0015] Optionally, the accelerated heat-aging processed sample in the heated second insulation oil is subjected to the voltage-withstanding test according to the preset initial voltage, voltage duration and voltage increasing gradient, including:

[0016] applying the initial voltage to the accelerated heat-aging processed sample in the heated second insulation oil, and maintaining the current applied voltage within the voltage duration;

[0017] increasing the voltage of the accelerated heat-aging processed sample within a unit duration based on the current applied voltage according to the voltage increasing gradient, and returning to the step of maintaining the current applied voltage within the voltage duration until the accelerated heat-aging processed sample is broken down.

[0018] Optionally, the oil paper to be evaluated is obtained, including:

[0019] obtaining a plurality of oil paper samples with the same size parameters;

[0020] placing the oil paper to be evaluated in the first insulation oil, including:

[0021] obtaining a plurality of beakers;

[0022] placing the first insulation oil in each beaker;

[0023] placing one oil paper sample in each beaker in which the first insulation oil has been placed;

[0024] The method further includes:

[0025] dividing each beaker in which the oil paper sample has been placed into four beaker groups; the number of beakers in the four beaker groups is the same;

[0026] in the four beaker groups, determining the first beaker group, the second beaker group and the third beaker group as the heat-aging test groups, and determining the fourth beaker group as the control group.

[0027] Optionally, the predefined temperature duration includes a first duration, a second duration and a third duration, the first duration is 5 consecutive days, the second duration is 10 consecutive days, and the third duration is 20 consecutive days; heating the first insulation oil to the preset accelerated heat-aging temperature, including:

[0028] heating the first insulation oil in each beaker in the first beaker group, the second beaker group and the third beaker group to the accelerated heat-aging temperature, respectively;

[0029] maintaining the temperature of the first insulating oil as the accelerated thermal aging temperature within a predefined temperature duration, to perform an accelerated thermal aging treatment on the oil paper to be evaluated, comprising:

[0030] maintaining the temperature of the first insulating oil in each beaker of the first beaker group, the second beaker group and the third beaker group as the accelerated thermal aging temperature within the first duration, the second duration and the third duration respectively;

[0031] obtaining the post-accelerated thermal aging treatment sample, comprising:

[0032] each oil paper sample in each beaker after the accelerated thermal aging treatment is determined as the post-accelerated thermal aging treatment sample.

[0033] Optionally, placing the post-accelerated thermal aging treatment sample in the second insulating oil for performing the AC breakdown, comprising:

[0034] placing the second insulating oil and one oil paper sample not subjected to the accelerated thermal aging treatment in each test container of the first test container group, the second test container group and the third test container group respectively;

[0035] placing the second insulating oil and one post-accelerated thermal aging treatment sample from the first beaker group in each test container of the fourth test container group, the fifth test container group and the sixth test container group respectively;

[0036] placing the second insulating oil and one post-accelerated thermal aging treatment sample from the second beaker group in each test container of the seventh test container group, the eighth test container group and the ninth test container group respectively;

[0037] placing the second insulating oil and one post-accelerated thermal aging treatment sample from the third beaker group in each test container of the tenth test container group, the eleventh test container group and the twelfth test container group respectively.

[0038] Optionally, the withstand voltage test temperature comprises: a first temperature, a second temperature and a third temperature; heating the second insulating oil to a preset withstand voltage test temperature, comprising:

[0039] heating the second insulating oil in the first test container group, the second test container group and the third test container group to the first temperature, the second temperature and the third temperature respectively;

[0040] heating the second insulating oil in the fourth test container group, the fifth test container group and the sixth test container group to the first temperature, the second temperature and the third temperature respectively;

[0041] heating the second insulating oil in the seventh test container group, the eighth test container group and the ninth test container group to the first temperature, the second temperature and the third temperature respectively;

[0042] The second insulating oil in the tenth test container group, the eleventh test container group and the twelfth test container group is heated to the first temperature, the second temperature and the third temperature respectively.

[0043] Optionally, the voltage duration time includes: a fourth time length, a fifth time length and a sixth time length; and the accelerated thermal aging treated sample in the heated second insulating oil is subjected to a withstand voltage test according to the preset initial voltage, the voltage duration time and the voltage increasing gradient, including:

[0044] For any test container group: all the oil-paper samples or the accelerated thermal aging treated samples in the heated second insulating oil in the test container group are divided into a first part, a second part and a third part, and the first part, the second part and the third part are subjected to a withstand voltage test according to the fourth time length, the fifth time length and the sixth time length under the same initial voltage and voltage increasing gradient;

[0045] When the accelerated thermal aging treated sample is broken down during the withstand voltage test, the withstand voltage duration time of the accelerated thermal aging treated sample is determined, including:

[0046] The withstand voltage duration time of the oil-paper sample and the accelerated thermal aging treated sample is determined in each withstand voltage test respectively;

[0047] Optionally, the method further includes:

[0048] The AC breakdown field strength of the oil-paper sample and the accelerated thermal aging treated sample is determined in each withstand voltage test respectively;

[0049] Based on the test data of each withstand voltage test, all unknown coefficients in the predefined insulation life assessment model are fitted; the test data includes: the withstand voltage test temperature and the AC breakdown field strength;

[0050] The oil-paper insulation life is assessed by using the insulation life assessment model in which all unknown coefficients have been fitted.

[0051] An oil-paper insulation life assessment device includes: a first obtaining unit, a first placing unit, a first heating unit, a first holding unit, a second obtaining unit, a second placing unit, a second heating unit, a test unit, a first determining unit and an assessment unit; wherein:

[0052] The first obtaining unit is configured to obtain the oil-paper to be assessed.

[0053] The first placing unit is configured to place the oil-paper to be assessed in the first insulating oil.

[0054] The first heating unit is configured to heat the first insulating oil to a preset accelerated thermal aging temperature.

[0055] The first holding unit is configured to maintain the temperature of the first insulating oil as the accelerated thermal aging temperature for a predefined temperature maintaining duration, so as to perform the accelerated thermal aging treatment on the oil-paper to be evaluated.

[0056] The second obtaining unit is configured to obtain the sample after the accelerated thermal aging treatment.

[0057] The second placing unit is configured to place the sample after the accelerated thermal aging treatment into the second insulating oil.

[0058] The second heating unit is configured to heat the second insulating oil to a preset withstand voltage test temperature.

[0059] The test unit is configured to perform a withstand voltage test on the sample after the accelerated thermal aging treatment in the heated second insulating oil according to a preset initial voltage, a voltage maintaining duration and a voltage increasing gradient.

[0060] The first determining unit is configured to determine a withstand voltage duration of the sample after the accelerated thermal aging treatment when the sample after the accelerated thermal aging treatment is broken down during the withstand voltage test.

[0061] The evaluation unit is configured to evaluate the insulation life of the oil-paper to be evaluated based on the withstand voltage duration of the sample after the accelerated thermal aging treatment.

[0062] Optionally, the test unit comprises a first applying unit, a second holding unit and a voltage increasing unit, wherein:

[0063] The first applying unit is configured to apply an initial voltage to the sample after the accelerated thermal aging treatment in the heated second insulating oil.

[0064] The second holding unit is configured to maintain the current applied voltage for a voltage maintaining duration.

[0065] The voltage increasing unit is configured to increase the voltage of the sample after the accelerated thermal aging treatment according to the voltage increasing gradient in a unit duration based on the current applied voltage, trigger the second holding unit, and break down the sample after the accelerated thermal aging treatment.

[0066] The oil-paper insulation life evaluation method and device provided by the embodiment can obtain the oil paper to be evaluated, place the oil paper to be evaluated into the first insulating oil, heat the first insulating oil to a preset accelerated thermal aging temperature, and maintain the temperature of the first insulating oil as the accelerated thermal aging temperature for a predefined temperature duration, so as to perform accelerated thermal aging processing on the oil paper to be evaluated, obtain a sample after the accelerated thermal aging processing, place the sample after the accelerated thermal aging processing into the second insulating oil, and heat the second insulating oil to a preset withstand voltage test temperature. The sample after the accelerated thermal aging processing in the heated second insulating oil is subjected to a withstand voltage test according to a preset initial voltage, a voltage duration and a voltage rising gradient. When the sample after the accelerated thermal aging processing is broken down during the withstand voltage test, the duration of the withstand voltage of the sample after the accelerated thermal aging processing is determined, and the insulation life of the oil paper to be evaluated is evaluated based on the duration of the withstand voltage of the sample after the accelerated thermal aging processing. The oil-paper insulation life can be effectively evaluated, so that the reliability of the oil-paper insulation performance can be determined.

[0067] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0068] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without creating any creative labor.

[0069] Figure 1 A flow chart of a first oil-paper insulation life evaluation method provided by an embodiment of the present application is shown;

[0070] Figure 2 A principle diagram of a withstand voltage test provided by an embodiment of the present application is shown;

[0071] Figure 3 A life model diagram of a non-aged sample provided by an embodiment of the present application is shown;

[0072] Figure 4 A life model diagram of a 5-day aged sample provided by an embodiment of the present application is shown;

[0073] Figure 5 A life model diagram of a 10-day aged sample provided by an embodiment of the present application is shown;

[0074] Figure 6A life model diagram of a 20-day aging sample is shown;

[0075] Figure 7 A structure schematic diagram of an oil-paper insulation life evaluation device is shown. DETAILED DESCRIPTION

[0076] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be accurately conveyed to those skilled in the art.

[0077] As shown in Figure 1 , the present embodiment proposes a first oil-paper insulation life evaluation method, which can include the following steps.

[0078] S101, obtaining oil paper to be evaluated;

[0079] The oil paper to be evaluated can be oil paper whose remaining insulation life needs to be evaluated.

[0080] Optionally, step S101 can include:

[0081] obtaining oil paper;

[0082] drying the oil paper to obtain dried oil paper;

[0083] cutting the dried oil paper to obtain the oil paper to be evaluated with predefined size parameters.

[0084] Optionally, the present application can place the oil paper in a beaker, place the beaker with the oil paper in an oven, and control the temperature in the oven to be a drying temperature (such as 70 degrees Celsius) for a certain period of time (such as 24 consecutive hours) to dry the oil paper.

[0085] The predefined size parameters can be set by a technician according to actual conditions, and the present application does not limit this. For example, the length can be 40 mm and the width can be 25 mm.

[0086] S102, placing the oil paper to be evaluated into first insulation oil;

[0087] The first insulation oil can be insulation oil that immerses the oil paper in an oil-immersed current transformer.

[0088] S103, heating the first insulation oil to a preset accelerated thermal aging temperature;

[0089] Specifically, the application can heat the first insulating oil until the first insulating oil is heated to the accelerated thermal aging temperature after the oil paper to be evaluated is placed in the first insulating oil.

[0090] The accelerated thermal aging temperature can be a temperature for performing accelerated thermal aging treatment on the oil paper to be evaluated to evaluate the insulation aging characteristics of the oil paper to be evaluated. It should be noted that the accelerated thermal aging temperature can be formulated by a technician according to actual conditions, and the application does not limit this. Optionally, the accelerated thermal aging temperature can be 130 degrees Celsius.

[0091] It should be noted that the application can make the oil paper sample reach the expected effect of aging in a short time by applying the accelerated thermal aging temperature to the oil paper sample in the environment of immersing the first insulating oil, simulate the real running state, meet the requirements of subsequent insulation state evaluation work, and deepen the understanding of the thermal aging process of the current transformer oil paper insulation.

[0092] S104, maintaining the temperature of the first insulating oil as the accelerated thermal aging temperature for a predefined temperature duration to perform accelerated thermal aging treatment on the oil paper to be evaluated;

[0093] The temperature duration can be the duration for which the temperature of the first insulating oil is maintained at the accelerated thermal aging temperature after the temperature of the first insulating oil reaches the accelerated thermal aging temperature. It should be noted that the temperature duration can be set by a technician according to actual conditions, and the application does not limit this.

[0094] Optionally, the application can perform constant temperature treatment on the first insulating oil for the temperature duration after the first insulating oil is heated to the accelerated thermal aging temperature, so that the temperature of the first insulating oil can be maintained at the accelerated thermal aging temperature for the temperature duration.

[0095] Optionally, the application can heat the first insulating oil to the accelerated thermal aging temperature as soon as possible and maintain it at the accelerated thermal aging temperature for the temperature duration.

[0096] Optionally, the application can place the first insulating oil in a beaker, and then place the oil paper to be evaluated in the first insulating oil. The first insulating oil can be heated by heating the beaker, so that the oil paper to be evaluated can be heated in the environment of immersing the first insulating oil, that is, the oil paper to be evaluated can be subjected to accelerated thermal aging treatment in the simulated actual working environment.

[0097] Specifically, the application can place the beaker containing the first insulating oil and the oil paper to be evaluated into an oven, and set and maintain the temperature in the oven as the accelerated thermal aging temperature for the temperature duration to heat the first insulating oil and the oil paper to be evaluated.

[0098] S105, obtain the sample after the accelerated heat aging treatment;

[0099] The sample after the accelerated heat aging treatment can be the sample to be evaluated after the accelerated heat aging treatment.

[0100] It should be noted that the thickness of the sample after the accelerated heat aging treatment can be measured after the sample after the accelerated heat aging treatment is obtained.

[0101] Optionally, the thickness of the sample after the accelerated heat aging treatment can be measured at different positions of the sample after the accelerated heat aging treatment by using the thickness measuring device, and the average value of the thickness of the sample after the accelerated heat aging treatment at different positions measured is determined as the thickness of the sample after the accelerated heat aging treatment.

[0102] Specifically, the thickness measuring device with a thickness of 0.001 mm or higher precision can be used. Different positions of the sample after the accelerated heat aging treatment are selected for thickness measurement, the thickness measured at each position is recorded, and the average value of all the thicknesses measured is calculated, and the average value obtained is used as the thickness of the sample after the accelerated heat aging treatment.

[0103] S106, placing the sample after the accelerated heat aging treatment into the second insulating oil;

[0104] The second insulating oil can be an insulating oil used for immersing the sample after the accelerated heat aging treatment to perform a withstand voltage test on the sample after the accelerated heat aging treatment.

[0105] It should be noted that the withstand voltage test can be a test for evaluating the remaining insulation life of the sample after the accelerated heat aging treatment.

[0106] Specifically, the second insulating oil can be placed in a container used for the withstand voltage test, and then the sample after the accelerated heat aging treatment is placed in the second insulating oil in the container.

[0107] S107, heating the second insulating oil to a preset withstand voltage test temperature;

[0108] The withstand voltage test temperature can be a temperature used for the withstand voltage test on the sample after the accelerated heat aging treatment.

[0109] Specifically, the second insulating oil can be placed in a container used for the withstand voltage test, and the second insulating oil is heated by heating the container, thereby heating the sample after the accelerated heat aging treatment.

[0110] S108, performing a withstand voltage test on the sample after the accelerated heat aging treatment in the heated second insulating oil according to a preset initial voltage, voltage duration, and voltage rising gradient;

[0111] Specifically, the present application can start the withstand voltage test on the sample after accelerated heat aging treatment after the second insulating oil is heated to the withstand voltage test temperature.

[0112] Specifically, the schematic diagram of the withstand voltage test can be as shown in Figure 2 In Figure 2 , T1 is the primary side voltage winding, T2 is the secondary side voltage winding, D is a diode, R is a resistor, A is an ammeter, and V is a voltmeter. The second insulating oil is placed in the container, and the oil paper sample is immersed in the second insulating oil. One side of the oil paper sample can be connected to a high voltage electrode, and the other side can be connected to a ground electrode.

[0113] Specifically, the present application can perform the withstand voltage test on the sample after accelerated heat aging treatment by using the withstand voltage test device as shown in Figure 2 , and the voltage measurement value of the voltmeter V can be read and determined as the alternating voltage applied to the sample after accelerated heat aging treatment.

[0114] Optionally, step S108 can include:

[0115] applying an initial voltage to the sample after accelerated heat aging treatment in the heated second insulating oil, and maintaining the current applied voltage within the voltage duration;

[0116] increasing the voltage of the sample after accelerated heat aging treatment according to the voltage increasing gradient within the unit time based on the current applied voltage, returning to the step of maintaining the current applied voltage within the voltage duration, until the sample after accelerated heat aging treatment is broken down.

[0117] Specifically, an initial voltage is applied to the sample after accelerated heat aging treatment in the second insulating oil, and the current applied voltage, i.e. the initial voltage, is maintained within the voltage duration. Then, the voltage of the sample after accelerated heat aging treatment is increased according to the voltage increasing gradient within the unit time based on the current applied voltage. After the voltage increasing is completed, the current applied voltage is maintained within the voltage duration, and then the voltage of the sample after accelerated heat aging treatment is increased again according to the voltage increasing gradient within the unit time based on the current applied voltage. This process is repeated until the sample after accelerated heat aging treatment is broken down.

[0118] S109, when the sample after accelerated heat aging treatment is broken down during the withstand voltage test, determining the withstand voltage duration of the sample after accelerated heat aging treatment;

[0119] The withstand voltage duration can be the duration experienced from the start of the withstand voltage test on the sample after accelerated heat aging treatment to the breakdown of the sample after accelerated heat aging treatment during the withstand voltage test.

[0120] Specifically, the application can record the related test parameters in the test, such as thickness, AC breakdown voltage, AC breakdown field strength and pressure duration, during the pressure test of the sample after the accelerated heat aging treatment.

[0121] In S110, the insulation life of the oil paper to be evaluated is evaluated based on the pressure duration of the sample after the accelerated heat aging treatment.

[0122] Specifically, the application can evaluate the remaining insulation life of the oil paper to be evaluated based on the pressure duration of the sample after the accelerated heat aging treatment.

[0123] Optionally, the application can directly determine the pressure duration as the remaining insulation life of the oil paper to be evaluated.

[0124] Optionally, the application can multiply the pressure duration by a predefined coefficient after obtaining the pressure duration, and determine the multiplied value as the remaining insulation life of the oil paper to be evaluated.

[0125] Optionally, the application can determine the unknown coefficient in the model for predicting the remaining insulation life of the oil paper to be evaluated based on the pressure duration, and then use the model to evaluate the remaining insulation life of the oil paper.

[0126] Optionally, the application can perform repeated pressure tests on the sample after the accelerated heat aging treatment, record the pressure duration in each pressure test, and evaluate the remaining insulation life of the oil paper to be evaluated based on the pressure duration. Specifically, the application can obtain multiple samples after the accelerated heat aging treatment of the same type and size through the same drying, cutting and accelerated heat aging treatment process, and perform pressure tests on each sample after the accelerated heat aging treatment, respectively, record the pressure duration of each sample after the accelerated heat aging treatment, and evaluate the remaining insulation life of the oil paper to be evaluated through the pressure duration.

[0127] Optionally, the application can also perform pressure tests on the sample after the accelerated heat aging treatment under different test conditions, determine the pressure duration of the sample after the accelerated heat aging treatment under different test conditions and compare them, and analyze the insulation life of the sample after the accelerated heat aging treatment under different conditions.

[0128] It should be noted that when the evaluated insulation life of the oil paper is large, the application can determine that the current insulation performance of the oil paper has high reliability; and when the evaluated insulation life of the oil paper is small, the application can determine that the insulation performance of the sample after the accelerated heat aging treatment does not meet the requirements, at which time the oil paper can be replaced in time to ensure that the insulation performance of the oil paper in the current transformer meets the working requirements, effectively avoiding insulation failure of the current transformer.

[0129] The oil-paper insulation life evaluation method provided in the embodiment can obtain the oil-paper to be evaluated, place the oil-paper to be evaluated into the first insulating oil, heat the first insulating oil to a preset accelerated thermal aging temperature, and maintain the temperature of the first insulating oil as the accelerated thermal aging temperature for a predefined temperature duration, so as to perform accelerated thermal aging processing on the oil-paper to be evaluated, obtain a sample after the accelerated thermal aging processing, place the sample after the accelerated thermal aging processing into the second insulating oil, and heat the second insulating oil to a preset withstand voltage test temperature. The sample after the accelerated thermal aging processing in the heated second insulating oil is subjected to a withstand voltage test according to a preset initial voltage, a voltage duration and a voltage rising gradient. When the sample after the accelerated thermal aging processing is broken down during the withstand voltage test, the withstand voltage duration of the sample after the accelerated thermal aging processing is determined. The insulation life of the oil-paper to be evaluated is evaluated based on the withstand voltage duration of the sample after the accelerated thermal aging processing. The oil-paper insulation life can be effectively evaluated, so that the reliability of the oil-paper insulation performance can be determined.

[0130] Based on Figure 1 The second oil-paper insulation life evaluation method is provided in the embodiment. The method can include the following steps.

[0131] S201, obtaining a plurality of oil-paper samples with the same size parameters;

[0132] It should be noted that the step S201 can be an implementation process of the above step S101.

[0133] Specifically, the plurality of oil-paper samples with the same predefined size parameters can be obtained.

[0134] It should be noted that the insulating oil and the oil-paper samples can be placed in a plurality of beakers, and the oil-paper samples in the plurality of beakers can be subjected to accelerated thermal aging processing for different temperature durations. Then, the oil-paper samples after the accelerated thermal aging processing can be subjected to withstand voltage tests respectively, and the AC breakdown field strength and the withstand voltage duration can be recorded. The unknown coefficients in the insulation life evaluation model of the oil-paper can be determined based on the AC breakdown field strength and the withstand voltage duration, and the insulation life evaluation model with the known coefficients can be obtained. The insulation life evaluation model can be used to evaluate the insulation life of the oil-paper, and the insulation life of the oil-paper can be further effectively evaluated.

[0135] S202, obtaining a plurality of beakers;

[0136] It can be understood that, in addition to the duration of the accelerated thermal aging processing, the factors affecting the comparative evaluation can all be the same. The types, sizes and volumes of the beakers can all be the same.

[0137] S203, placing the first insulating oil in each beaker;

[0138] Specifically, the volume of the first insulating oil placed in each beaker can be the same.

[0139] S204, placing one oil-paper sample in each beaker in which the first insulating oil has been placed;

[0140] It should be noted that steps S202, S203 and S204 can be a specific implementation method of step S102.

[0141] S205, dividing the beakers in which the oil-paper samples have been placed into four beaker groups; the number of beakers in the four beaker groups is the same;

[0142] Optionally, the total number of beakers can be a multiple of 4. For example, the total number of beakers can be 48, and the number of beakers in each beaker group can be 12.

[0143] It should be noted that each beaker in a beaker group can be used to place insulating oil and an oil-paper sample, and the same duration of accelerated thermal aging treatment is performed, that is, the same repeated test is performed on multiple oil-paper samples under the same condition, the data obtained by the repeated test under the same condition is used for insulation performance evaluation, and the data accuracy and test reliability are improved.

[0144] S206, determining the first beaker group, the second beaker group and the third beaker group as the thermal aging test groups, and determining the fourth beaker group as the control group;

[0145] In the method, the predefined temperature duration can include a first duration, a second duration and a third duration, the first duration is 5 consecutive days, the second duration is 10 consecutive days, and the third duration is 20 consecutive days.

[0146] S207, heating the first insulating oil in each beaker in the first beaker group, the second beaker group and the third beaker group to an accelerated thermal aging temperature;

[0147] Specifically, the first insulating oil in each beaker of the first beaker group, the second beaker group and the third beaker group can be heated simultaneously by the same heating method.

[0148] It should be noted that step S207 can be an implementation process of the above step S103.

[0149] S208, maintaining the temperature of the first insulating oil in each beaker of the first beaker group, the second beaker group and the third beaker group at the accelerated thermal aging temperature for the first duration, the second duration and the third duration, respectively;

[0150] Specifically, the application can keep the temperature of the first insulating oil in each beaker in the first beaker group as the accelerated thermal aging temperature within a first time length; keep the temperature of the first insulating oil in each beaker in the second beaker group as the accelerated thermal aging temperature within a second time length; and keep the temperature of the first insulating oil in each beaker in the third beaker group as the accelerated thermal aging temperature within a third time length.

[0151] It should be noted that step S208 is an implementation process of step S104.

[0152] Optionally, the beakers in the same beaker group can be placed in the same oven for accelerated thermal aging treatment, and the beakers in different beaker groups can be placed in different ovens for accelerated thermal aging treatment. For example, the application can place the beakers in the first beaker group in the first oven for accelerated thermal aging treatment, place the beakers in the second beaker group in the second oven for accelerated thermal aging treatment, and place the beakers in the third beaker group in the third oven for accelerated thermal aging treatment.

[0153] Optionally, when the internal space of the oven is large, the application can also place the beakers in each beaker group in the same oven for accelerated thermal aging treatment. At this time, the application can place the beakers in different beaker groups in corresponding areas in the oven to facilitate the identification of the beaker groups and the operation of the beaker groups. For example, when the first temperature lasts for a certain time length, all the beakers in the first beaker group can be uniformly taken out from the corresponding area in the oven.

[0154] S209, each oil-paper sample after accelerated thermal aging treatment is determined as an accelerated thermal aging treatment sample.

[0155] It should be noted that step S209 can be an implementation process of step S105.

[0156] Specifically, the application can determine the oil-paper samples in the beakers of all beaker groups after accelerated thermal aging treatment as accelerated thermal aging treatment samples. For example, the application can determine the oil-paper sample in the first beaker of the first beaker group after accelerated thermal aging treatment as an accelerated thermal aging treatment sample, and determine the oil-paper sample in the second beaker of the second beaker group after accelerated thermal aging treatment as an accelerated thermal aging treatment sample.

[0157] S210, the thickness of each accelerated thermal aging treatment sample is measured respectively;

[0158] S211, the second insulating oil and an oil-paper sample not subjected to accelerated thermal aging treatment are placed in each test container of the first test container group, the second test container group and the third test container group respectively.

[0159] It should be noted that each test container group can include a certain number of test containers. Specifically, the number of test containers in each test container group can be the same or different. Each test container can be placed with the second insulating oil and an oil-paper sample.

[0160] The test container can be a beaker.

[0161] Specifically, the test containers in each test container group can be subjected to pressure test. The present application can set different test conditions, and the oil-paper samples in different test container groups are subjected to pressure test under different test conditions to obtain test results under different test conditions. The insulation life of the oil-paper sample is evaluated based on the test results.

[0162] The oil-paper samples in the first test container group, the second test container group and the third test container group can be from the oil-paper samples in the fourth beaker group, i.e. the oil-paper that has not been subjected to accelerated thermal aging treatment.

[0163] S212, respectively in the fourth test container group, the fifth test container group and the sixth test container group, placing the second insulating oil and an accelerated thermal aging treated sample from the first beaker group in each test container;

[0164] S213, respectively in the seventh test container group, the eighth test container group and the ninth test container group, placing the second insulating oil and an accelerated thermal aging treated sample from the second beaker group in each test container;

[0165] S214, respectively in the tenth test container group, the eleventh test container group and the twelfth test container group, placing the second insulating oil and an accelerated thermal aging treated sample from the third beaker group in each test container.

[0166] It can be understood that the fourth test container group, the fifth test container group, the sixth test container group, the seventh test container group, the eighth test container group, the ninth test container group, the tenth test container group, the eleventh test container group and the twelfth test container group can include a certain number of test containers. Optionally, the number of test containers in all test container groups can be the same.

[0167] It should be noted that steps S211, S212, S213 and S214 can be an implementation process of step 206.

[0168] Optionally, in the method, the pressure resistance test temperature comprises: a first temperature, a second temperature and a third temperature; it should be noted that the first temperature, the second temperature and the third temperature can be set by the skilled person according to the actual situation, and the present application does not limit this. For example, the first temperature can be 20 degrees Celsius, the second temperature can be 50 degrees Celsius, and the third temperature can be 80 degrees Celsius.

[0169] S215, respectively, the second insulating oil in the first test container group, the second test container group and the third test container group is heated to the first temperature, the second temperature and the third temperature;

[0170] Specifically, the present application can heat the second insulating oil in each test container in the first test container group to the first temperature; heat the second insulating oil in each test container in the second test container group to the second temperature; heat the second insulating oil in each test container in the third test container group to the third temperature.

[0171] S216, respectively, the second insulating oil in the fourth test container group, the fifth test container group and the sixth test container group is heated to the first temperature, the second temperature and the third temperature;

[0172] Specifically, the present application can heat the second insulating oil in each test container in the fourth test container group to the first temperature; heat the second insulating oil in each test container in the fifth test container group to the second temperature; heat the second insulating oil in each test container in the sixth test container group to the third temperature.

[0173] S217, respectively, the second insulating oil in the seventh test container group, the eighth test container group and the ninth test container group is heated to the first temperature, the second temperature and the third temperature;

[0174] Specifically, the present application can heat the second insulating oil in each test container in the seventh test container group to the first temperature; heat the second insulating oil in each test container in the eighth test container group to the second temperature; heat the second insulating oil in each test container in the ninth test container group to the third temperature.

[0175] S218, respectively, the second insulating oil in the tenth test container group, the eleventh test container group and the twelfth test container group is heated to the first temperature, the second temperature and the third temperature.

[0176] Specifically, the present application can heat the second insulating oil in each test container in the tenth test container group to the first temperature; heat the second insulating oil in each test container in the eleventh test container group to the second temperature; heat the second insulating oil in each test container in the twelfth test container group to the third temperature.

[0177] It should be noted that steps S215, S216, S217 and S218 can be an implementation process of the above step S207.

[0178] Optionally, in the method, the voltage duration includes a fourth duration, a fifth duration and a sixth duration; it should be noted that the fourth duration, the fifth duration and the sixth duration can be set by the technician according to the actual situation, and the present application does not limit this. For example, the fourth duration can be 20 seconds, the fifth duration can be 60 seconds, and the sixth duration can be 120 seconds.

[0179] S219, for any test container group: divide all the oil-paper samples or the samples after accelerated thermal aging treatment in the heated second insulating oil in the test container group into first part samples, second part samples and third part samples, and perform pressure resistance tests on the first part samples, the second part samples and the third part samples respectively under the same initial voltage and voltage rise gradient and for the fourth duration, the fifth duration and the sixth duration;

[0180] It can be understood that the test containers in the first test container group, the second test container group and the third test container group all contain oil-paper samples that have not been subjected to accelerated thermal aging treatment, and the test containers in the other test container groups all contain samples after accelerated thermal aging treatment.

[0181] Specifically, for a certain test container group, the present application can divide all the test containers in the test container group into three parts of test containers in total, i.e., a first part, a second part and a third part. At this time, in the test container group, the samples in the test containers of the first part are the first part samples, the samples in the test containers of the second part are the second part samples, and the samples in the test containers of the third part are the third part samples. The present application can perform pressure resistance tests on the samples in the test containers of the first part according to the initial voltage, the voltage rise gradient and the fourth duration; perform pressure resistance tests on the samples in the test containers of the second part according to the initial voltage, the voltage rise gradient and the fifth duration; and perform pressure resistance tests on the samples in the test containers of the third part according to the initial voltage, the voltage rise gradient and the sixth duration.

[0182] It should be noted that step S219 can be an implementation process of the above step S208.

[0183] S220, in each pressure resistance test, determine the pressure resistance duration of the oil-paper samples and the samples after accelerated thermal aging treatment;

[0184] It can be understood that the test conditions of the withstand voltage test performed by a certain part of the samples in a certain test container group are the same. For example, the test conditions of the withstand voltage test performed by the first part of the samples in the first test container group are the same. Specifically, the present application regards the withstand voltage test performed by the samples in a certain part of the samples as repeated tests on the same sample, and when evaluating the insulation life of the part of the samples, a representative value can be taken from the withstand voltage duration of the part of the samples, and the insulation life is evaluated according to the representative value.

[0185] In the present application, the withstand voltage duration of each sample in a certain part of the samples can be processed by using a weibull distribution model, and a representative value is determined as the withstand voltage duration of the part of the samples. It should be noted that in the process of processing by using the weibull distribution model, the shape parameter and the scale parameter of the weibull distribution can be obtained.

[0186] Specifically, the present application can obtain the withstand voltage duration of different parts of the samples in each sample container group.

[0187] It should be noted that step S220 can be an implementation process of step S109 described above.

[0188] S221, based on the withstand voltage duration of each oil-paper sample and each accelerated heat aging treated sample, evaluating the insulation life of the oil-paper to be evaluated.

[0189] Specifically, after obtaining the withstand voltage duration of different parts of the samples in each sample container group, the present application can analyze the insulation performance and the insulation life of the oil-paper sample under different accelerated heat aging treatment conditions and different withstand voltage test conditions according to the withstand voltage duration of different parts of the samples in each sample container group.

[0190] It should be noted that step S221 can be an implementation process of step S110 described above.

[0191] Optionally, the method can further comprise:

[0192] S222, respectively in each withstand voltage test, determining the AC breakdown field strength of the oil-paper sample and the accelerated heat aging treated sample;

[0193] S223, based on the test data of each withstand voltage test, fitting all unknown coefficients in the predefined insulation life evaluation model; the test data includes the withstand voltage test temperature and the AC breakdown field strength;

[0194] It should be noted that the inventors of the present application found through research experiments that the insulation life of oil paper is related to temperature and field strength, and the oil paper can be subjected to voltage withstand test at a certain voltage withstand test temperature, the AC breakdown field strength and voltage withstand duration of the oil paper are recorded, and the relationship between the insulation life of the oil paper and the AC breakdown field strength and voltage withstand duration is analyzed.

[0195] S224, using the insulation life evaluation model in which all unknown coefficients have been fitted, to evaluate the insulation life of the oil paper.

[0196] Specifically, during the voltage withstand test of the partial samples, the present application can record the AC breakdown voltage and thickness of the samples, and calculate the AC breakdown field strength of the samples according to the AC breakdown voltage and thickness.

[0197] The test data can include voltage withstand test temperature, voltage duration, AC breakdown field strength, voltage withstand duration, last duration, and shape parameter and scale parameter of weibull distribution obtained by using weibull distribution model processing method.

[0198] Specifically, the independent variable in the insulation life evaluation model can be voltage withstand test temperature and AC breakdown field strength, and the dependent variable can be insulation life. The insulation life evaluation model can include one or more unknown coefficients.

[0199] Alternatively, the insulation life evaluation model can be:

[0200]

[0201] Wherein, L can be insulation life, A1, A2, A3, A4 and A5 can all be unknown coefficients, T can be voltage withstand test temperature, and E can be AC breakdown field strength. It should be noted that the insulation life evaluation model is proposed by the inventors of the present application through research experiments.

[0202] Specifically, the present application can use the test data obtained by subjecting the partial samples to voltage withstand test to fit all unknown coefficients in the insulation life evaluation model, and solve all unknown coefficients. Then, the present application can use the insulation life evaluation model to evaluate the insulation life of the oil paper.

[0203] To better illustrate the above-mentioned second oil paper insulation performance evaluation method, this embodiment proposes and illustrates the following example 1.

[0204] Example 1, place the oil paper with a larger area and the first insulating oil in the same type of beaker respectively, then place the beaker in an oven, set the temperature in the oven to 70 degrees Celsius, dry and degas the oil paper and the first insulating oil; wherein the drying duration can be 24 hours.

[0205] After drying, the oil paper is cut into oil paper samples with a length of 40 mm and a width of 25 mm;

[0206] The 48 beakers are divided into four groups, each group including 12 beakers, and each beaker contains an oil paper sample and a certain volume of the first insulating oil. Three groups of beakers are determined as the first beaker group, the second beaker group, and the third beaker group (i.e., the thermal aging experiment group), and the remaining one group of beakers is the fourth beaker group (i.e., the control group).

[0207] It should be noted that the volume of the first insulating oil and the size parameters of the oil paper sample in each beaker can be the same, and the ratio of the first insulating oil to the oil paper sample can be 10:1.

[0208] After that, the first beaker group can be placed in the first oven for heating, the temperature in the first oven is set to 130 degrees Celsius, and the heating period is set to 5 consecutive days, so as to perform accelerated thermal aging treatment on each oil paper sample in the first beaker group. The second beaker group is placed in the second oven for heating, the temperature in the second oven is set to 130 degrees Celsius, and the heating period is set to 10 consecutive days, so as to perform accelerated thermal aging treatment on each oil paper sample in the second beaker group. The third beaker group is placed in the third oven for heating, the temperature in the third oven is set to 130 degrees Celsius, and the heating period is set to 20 consecutive days, so as to perform accelerated thermal aging treatment on each oil paper sample in the third beaker group. It should be noted that each oven can only contain oil paper samples and cannot mix other types of samples.

[0209] In each oven, the spacing between the beakers can be at least 20 mm.

[0210] At the end of the heating period, the beakers can be taken out of the corresponding oven, and the accelerated thermal aging treated samples are obtained. After cooling to room temperature, the accelerated thermal aging treated samples are sealed and stored.

[0211] After that, the thickness of each accelerated thermal aging treated sample from the first beaker group, the second beaker group, and the third beaker group, and the thickness of each oil paper sample from the fourth beaker group can be measured using a 0.001 mm thickness gauge or a thickness measuring device with higher precision. When measuring the thickness of a sample, the thickness of the sample can be measured at different positions multiple times, and the average thickness of the multiple measurements is taken as the thickness of the sample. The thickness of the measured sample can be recorded.

[0212] Afterwards, the application can obtain 432 test containers, and divide the 432 test containers into twelve test container groups, i.e., a first test container group, a second test container group, a third test container group, a fourth test container group, a fifth test container group, a sixth test container group, a seventh test container group, an eighth test container group, a ninth test container group, a tenth test container group, an eleventh test container group, and a twelfth test container group. Each test container group can include 36 test containers, and all the test containers in each test container group can be divided into a first part container, a second part container, and a third part container, and each part container can include 12 test containers.

[0213] Specifically, the application can first place a certain volume of second insulating oil in each test container of each test container group. Afterwards, a certain sample is placed in the second insulating oil of each test container of each test container group. Specifically, the application can place one oil-paper sample from the fourth beaker group that has not been subjected to accelerated thermal aging treatment in each second insulating oil of the first test container group, the second test container group, and the third test sample container group; place one sample from the first beaker group that has been subjected to accelerated thermal aging treatment in each second insulating oil of the fourth test sample container group, the fifth test sample container group, and the sixth test sample container group; place one sample from the second beaker group that has been subjected to accelerated thermal aging treatment in each second insulating oil of the seventh test sample container group, the eighth test sample container group, and the ninth test sample container group; and place one sample from the third beaker group that has been subjected to accelerated thermal aging treatment in each second insulating oil of the tenth test sample container group, the eleventh test sample container group, and the twelfth test sample container group.

[0214] Afterwards, the application can heat the second insulating oil in all test containers in the first test container group to 20 degrees Celsius, and perform a withstand voltage test on the oil-paper sample in each test container of the first part container in the first test container group according to the withstand voltage test conditions of 20 degrees Celsius, an initial voltage of 0.5 kV, a voltage rising gradient of 500 V / s, and a voltage duration time of 20 seconds; perform a withstand voltage test on the oil-paper sample in each test container of the second part container in the first test container group according to the withstand voltage test conditions of 20 degrees Celsius, an initial voltage of 0.5 kV, a voltage rising gradient of 500 V / s, and a voltage duration time of 60 seconds; and perform a withstand voltage test on the oil-paper sample in each test container of the third part container in the first test container group according to the withstand voltage test conditions of 20 degrees Celsius, an initial voltage of 0.5 kV, a voltage rising gradient of 500 V / s, and a voltage duration time of 120 seconds.

[0215] At this time, the present application can obtain the oil paper sample pressure test data of each part container in the first test container group. For the pressure test data of each oil paper sample in a certain part container, the present application can determine the representative value and record it by using the processing method of weibull distribution model. The pressure test record table is shown in Table 1 as follows.

[0216] Table 1 Pressure test record table of unaged sample at 20℃ environment

[0217]

[0218] Wherein, the last duration can be the duration of the last applied voltage when the sample is broken down.

[0219] Wherein, the three rows of data recorded in Table 1 are the pressure test data of the oil paper sample at the same pressure test temperature, i.e. 20℃, and different voltage duration.

[0220] Specifically, the present application can obtain the pressure test data of three part containers of the second test container group at the same pressure test temperature, i.e. 50℃, and different voltage duration, according to the above processing process. As shown in Table 2.

[0221] Table 2 Pressure test record table of unaged sample at 50℃ environment

[0222]

[0223] Specifically, the present application can obtain the pressure test data of three part containers of the third test container group at the same pressure test temperature, i.e. 80℃, and different voltage duration, according to the above processing process. As shown in Table 3.

[0224] Table 3 Pressure test record table of unaged sample at 80℃ environment

[0225]

[0226] Specifically, the present application can obtain the pressure test data of three part containers of the fourth test container group, the fifth test container group, the sixth test container group, the seventh test container group, the eighth test container group, the ninth test container group, the tenth test container group, the eleventh test container group and the twelfth test container group under different pressure test conditions, according to the above processing process. As shown in Table 4, Table 5, Table 6, Table 7, Table 8, Table 9, Table 10, Table 11 and Table 12.

[0227] Table 4 Pressure test record table of 5-day aged sample at 20℃ environment

[0228]

[0229] Table 5: 50°C environmental aging for 5 days sample withstand voltage test record table

[0230]

[0231] Table 6: 80°C environmental aging for 5 days sample withstand voltage test record table

[0232]

[0233] It should be noted that Table 4, Table 5 and Table 6 are respectively the AC breakdown field strength, voltage duration and the last duration of the voltage test data of the 5-day-old sample at 20s, 60s and 120s of voltage duration under 20°C, 50°C and 80°C environment.

[0234] Table 7: 20°C environmental aging for 10 days sample withstand voltage test record table

[0235]

[0236] Table 8: 50°C environmental aging for 10 days sample withstand voltage test record table

[0237]

[0238] Table 9: 80°C environmental aging for 10 days sample withstand voltage test record table

[0239]

[0240] It should be noted that Table 7, Table 8 and Table 9 are respectively the AC breakdown field strength, voltage duration and the last duration of the voltage test data of the 10-day-old sample at 20s, 60s and 120s of voltage duration under 20°C, 50°C and 80°C environment.

[0241] Table 10: 20°C environmental aging for 20 days sample withstand voltage test record table

[0242]

[0243] Table 11: 50°C environmental aging for 20 days sample withstand voltage test record table

[0244]

[0245] Table 12: 80°C environmental aging for 20 days sample withstand voltage test record table

[0246]

[0247] It should be noted that Table 10, Table 11 and Table 12 are the AC breakdown field strength, voltage duration and last duration voltage test data of the 20-day aged sample at the voltage duration of 20s, 60s and 120s respectively under the environment of 20℃, 50℃ and 80℃.

[0248] Specifically, based on the voltage test data of the unaged oil paper sample, the accelerated heat aging treated sample aged for 5 days, 10 days and 20 days, the life model diagram as shown in Figure 3 、 Figure 4 、 Figure 5 and Figure 6 can be obtained. In Figure 3 、 Figure 4 、 Figure 5 and Figure 6 , the voltage duration can be the voltage duration, and the unit of temperature is K, i.e., Kelvin.

[0249] Among them, the present application can determine the AC breakdown field strength and voltage duration of the sample under different heat aging states and different voltage test temperatures according to the scale parameter of the Weibull distribution model.

[0250] Specifically, after obtaining the voltage test data of each voltage test, the present application can use the voltage test data to fit all unknown coefficients in the insulation life evaluation model, determine all unknown coefficients, and obtain the insulation life evaluation model with all known coefficients. Then, the present application can use the insulation life evaluation model to evaluate the insulation life of the oil paper sample and the accelerated heat aging treated sample, and further realize effective evaluation of the insulation life of the oil paper.

[0251] It should be noted that the present application can achieve the expected effect of aging in a shorter time by performing accelerated heat aging treatment on the oil paper sample, and use a multi-factor life model with the best fitting effect to fit the relationship between the insulation life of the oil paper and the voltage test temperature and the AC breakdown field strength, thereby predicting the life of the current transformer oil paper insulation under different operating conditions, helping the workers to understand the aging trend and law of the transformer internal cable paper, laying the foundation for the diagnosis of the operating state of the transformer equipment, and providing a reliable basis for stable operation of the equipment. The present application has the advantages of simple test method, convenient operation, strong universality and wide application range.

[0252] The oil paper insulation life evaluation method proposed in this embodiment can perform voltage test on the sample under different voltage test temperatures and voltage duration test conditions, obtain voltage test data, use the voltage test data to fit the unknown coefficients in the insulation life evaluation model, determine the insulation life evaluation model, and use the insulation life evaluation model to evaluate the insulation life of the oil paper, thereby further realizing effective evaluation of the insulation life of the oil paper.

[0253] With Figure 1 corresponding to the method shown in Figure 7 The embodiment provides an oil-paper insulation life evaluation device. The device can include: a first obtaining unit 101, a first placing unit 102, a first heating unit 103, a first holding unit 104, a second obtaining unit 105, a second placing unit 106, a second heating unit 107, a test unit 108, a first determining unit 109 and an evaluation unit 110; wherein:

[0254] The first obtaining unit 101 is configured to obtain oil paper to be evaluated.

[0255] The first placing unit 102 is configured to place the oil paper to be evaluated into first insulation oil.

[0256] The first heating unit 103 is configured to heat the first insulation oil to a preset accelerated thermal aging temperature.

[0257] The first holding unit 104 is configured to maintain the temperature of the first insulation oil at the accelerated thermal aging temperature for a predefined temperature duration, so as to perform accelerated thermal aging treatment on the oil paper to be evaluated.

[0258] The second obtaining unit 105 is configured to obtain a test sample after the accelerated thermal aging treatment.

[0259] The second placing unit 106 is configured to place the test sample after the accelerated thermal aging treatment into second insulation oil.

[0260] The second heating unit 107 is configured to heat the second insulation oil to a preset withstand voltage test temperature.

[0261] The test unit 108 is configured to perform a withstand voltage test on the test sample after the accelerated thermal aging treatment in the heated second insulation oil according to a preset initial voltage, a voltage duration and a voltage rising gradient.

[0262] The first determining unit 109 is configured to determine a withstand voltage duration of the test sample after the accelerated thermal aging treatment when the test sample after the accelerated thermal aging treatment is broken down during the withstand voltage test.

[0263] The evaluation unit 110 is configured to evaluate the insulation life of the oil paper to be evaluated based on the withstand voltage duration of the test sample after the accelerated thermal aging treatment.

[0264] It should be noted that the specific processing procedures of the first obtaining unit 101, the first placing unit 102, the first heating unit 103, the first holding unit 104, the second obtaining unit 105, the second placing unit 106, the second heating unit 107, the test unit 108, the first determining unit 109 and the evaluation unit 110 and the technical effects brought by the specific processing procedures can be referred to the description of the method shown in Figure 1The steps S101, S102, S103, S104, S105, S106, S107, S108, S109 and S110 in the method are not described herein again.

[0265] Optionally, the test unit 108 comprises a first application unit, a second holding unit and a voltage boosting unit, wherein:

[0266] The first application unit is configured to apply an initial voltage to the heated sample after the accelerated thermal aging treatment in the second insulating oil.

[0267] The second holding unit is configured to maintain the current applied voltage for a voltage duration.

[0268] The voltage boosting unit is configured to boost the voltage of the sample after the accelerated thermal aging treatment in the unit time according to the voltage boosting gradient on the basis of the current applied voltage, trigger the second holding unit, and until the sample after the accelerated thermal aging treatment is broken down.

[0269] The oil-paper insulation life evaluation device can place the oil-paper to be evaluated into the first insulating oil, heat the first insulating oil to a preset accelerated thermal aging temperature, maintain the temperature of the first insulating oil at the accelerated thermal aging temperature for a predefined temperature duration, perform accelerated thermal aging treatment on the oil-paper to be evaluated, obtain a sample after the accelerated thermal aging treatment, place the sample after the accelerated thermal aging treatment into the second insulating oil, heat the second insulating oil to a preset withstand voltage test temperature, perform a withstand voltage test on the sample after the accelerated thermal aging treatment in the heated second insulating oil according to a preset initial voltage, voltage duration and voltage boosting gradient, determine the withstand voltage duration of the sample after the accelerated thermal aging treatment when the sample after the accelerated thermal aging treatment is broken down during the withstand voltage test, and evaluate the insulation life of the oil-paper to be evaluated based on the withstand voltage duration of the sample after the accelerated thermal aging treatment. The oil-paper insulation life evaluation device can effectively evaluate the insulation life of the oil-paper, thereby determining the reliability of the insulation performance of the oil-paper.

[0270] It should be further understood that the terms "comprise", "comprising", or any other variant thereof are intended to cover non-exclusive inclusions, such that processes, methods, articles, or apparatuses that comprise a list of elements do not only include those elements, but can also include other elements not expressly listed, or can also include elements inherent in such processes, methods, articles, or apparatuses. Without more limitations, the element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0271] The above merely provides an example of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall fall into the scope of claims of the present application.

Claims

1. An oil-paper insulation life assessment method, characterized by, The method comprises the following steps: obtaining oil paper to be evaluated; placing the oil paper to be evaluated into first insulating oil, heating the first insulating oil to a preset accelerated thermal aging temperature, and keeping the temperature of the first insulating oil at the accelerated thermal aging temperature for a predefined temperature duration, so as to perform accelerated thermal aging treatment on the oil paper to be evaluated, and obtain a sample after accelerated thermal aging treatment; placing the sample after accelerated thermal aging treatment into second insulating oil, and heating the second insulating oil to a preset withstand voltage test temperature; wherein the second insulating oil is used to perform a withstand voltage test on the sample after accelerated thermal aging treatment; performing a withstand voltage test on the sample after accelerated thermal aging treatment in the heated second insulating oil according to a preset initial voltage, a voltage duration and a voltage increasing gradient; when the sample after accelerated thermal aging treatment is broken down during the withstand voltage test, determining the withstand voltage duration of the sample after accelerated thermal aging treatment; based on the withstand voltage duration of the sample after accelerated thermal aging treatment, evaluating the insulation life of the oil paper to be evaluated; wherein the step of performing a withstand voltage test on the sample after accelerated thermal aging treatment in the heated second insulating oil according to a preset initial voltage, a voltage duration and a voltage increasing gradient comprises: applying the initial voltage to the sample after accelerated thermal aging treatment in the heated second insulating oil, and keeping the current applied voltage for the voltage duration; increasing the voltage of the sample after accelerated thermal aging treatment according to the voltage increasing gradient in a unit time based on the current applied voltage, and returning to the step of keeping the current applied voltage for the voltage duration until the sample after accelerated thermal aging treatment is broken down; wherein the withstand voltage test temperature comprises a plurality of different temperatures; the voltage duration comprises a plurality of different durations; the method further comprises: respectively determining the AC breakdown field strength of the oil paper sample and the sample after accelerated thermal aging treatment in each withstand voltage test; based on the test data of each withstand voltage test, fitting all unknown coefficients in a predefined insulation life evaluation model; the test data comprises the withstand voltage test temperature and the AC breakdown field strength; using the insulation life evaluation model with all the fitted unknown coefficients to evaluate the insulation life of the oil paper.

2. The oil-paper insulation life assessment method according to claim 1, characterized in that, The step of obtaining the oil paper to be evaluated comprises: obtaining a plurality of oil paper samples with the same size parameters; the step of placing the oil paper to be evaluated into the first insulating oil comprises: obtaining a plurality of beakers; placing the first insulating oil in each of the beakers; placing one oil paper sample in each of the beakers in which the first insulating oil has been placed; the method further comprises: dividing the beakers in which the oil paper samples have been placed into four beaker groups; the number of beakers in the four beaker groups is the same; determining the first beaker group, the second beaker group and the third beaker group as the thermal aging test groups, and determining the fourth beaker group as the control group in the four beaker groups.

3. The oil-paper insulation life assessment method according to claim 2, characterized in that, The predefined temperature duration includes: a first duration, a second duration and a third duration, the first duration is 5 consecutive days, the second duration is 10 consecutive days, and the third duration is 20 consecutive days; the heating of the first insulating oil to a preset accelerated thermal aging temperature includes: Respectively heating the first insulating oil in each beaker in the first beaker group, the second beaker group and the third beaker group to the accelerated thermal aging temperature; The maintaining of the temperature of the first insulating oil at the accelerated thermal aging temperature within the predefined temperature duration to perform accelerated thermal aging treatment on the oil paper to be evaluated includes: Respectively maintaining the temperature of the first insulating oil in each beaker of the first beaker group, the second beaker group and the third beaker group at the accelerated thermal aging temperature within the first duration, the second duration and the third duration; The obtaining of the accelerated thermal aging treatment sample includes: Each oil paper sample in each beaker after the accelerated thermal aging treatment is determined as the accelerated thermal aging treatment sample.

4. The oil-paper insulation life assessment method according to claim 3, characterized in that, The placing of the accelerated thermal aging treatment sample in the second insulating oil for performing AC breakdown includes: Respectively placing the second insulating oil and one oil paper sample not subjected to accelerated thermal aging treatment in each test container of a first test container group, a second test container group and a third test container group; Respectively placing the second insulating oil and one accelerated thermal aging treatment sample from the first beaker group in each test container of a fourth test container group, a fifth test container group and a sixth test container group; Respectively placing the second insulating oil and one accelerated thermal aging treatment sample from the second beaker group in each test container of a seventh test container group, an eighth test container group and a ninth test container group; Respectively placing the second insulating oil and one accelerated thermal aging treatment sample from the third beaker group in each test container of a tenth test container group, an eleventh test container group and a twelfth test container group.

5. The oil-paper insulation life assessment method according to claim 4, characterized in that, The withstand voltage test temperature includes: a first temperature, a second temperature and a third temperature; the heating of the second insulating oil to a preset withstand voltage test temperature includes: Respectively heating the second insulating oil in the first test container group, the second test container group and the third test container group to the first temperature, the second temperature and the third temperature; Respectively heating the second insulating oil in the fourth test container group, the fifth test container group and the sixth test container group to the first temperature, the second temperature and the third temperature; Respectively heating the second insulating oil in the seventh test container group, the eighth test container group and the ninth test container group to the first temperature, the second temperature and the third temperature; Respectively heating the second insulating oil in the tenth test container group, the eleventh test container group and the twelfth test container group to the first temperature, the second temperature and the third temperature.

6. The oil-paper insulation life assessment method according to claim 5, characterized in that, The voltage duration includes a fourth duration, a fifth duration and a sixth duration; the withstand voltage test on the accelerated thermal aging processed sample in the heated second insulating oil according to the preset initial voltage, voltage duration and voltage increasing gradient includes: For any test container group, all the oil-paper samples or accelerated thermal aging processed samples in the heated second insulating oil in the test container group are divided into a first part sample, a second part sample and a third part sample, and the first part sample, the second part sample and the third part sample are respectively subjected to the withstand voltage test according to the fourth duration, the fifth duration and the sixth duration under the same initial voltage and voltage increasing gradient; When the accelerated thermal aging processed sample is broken down in the withstand voltage test, the voltage duration of the accelerated thermal aging processed sample is determined. The voltage duration of the oil-paper sample and the accelerated thermal aging processed sample is respectively determined in each withstand voltage test.

7. An oil-paper insulation life assessment device, characterized by, It includes: A first obtaining unit, a first placing unit, a first heating unit, a first holding unit, a second obtaining unit, a second placing unit, a second heating unit, a test unit, a first determining unit and an evaluation unit; wherein: The first obtaining unit is configured to obtain a to-be-evaluated oil-paper. The first placing unit is configured to place the to-be-evaluated oil-paper in a first insulating oil. The first heating unit is configured to heat the first insulating oil to a preset accelerated thermal aging temperature; wherein a second insulating oil is used to perform a withstand voltage test on an accelerated thermal aging processed sample. The first holding unit is configured to maintain the temperature of the first insulating oil at the accelerated thermal aging temperature for a predefined temperature duration, so as to perform accelerated thermal aging processing on the to-be-evaluated oil-paper. The second obtaining unit is configured to obtain an accelerated thermal aging processed sample. The second placing unit is configured to place the accelerated thermal aging processed sample in a second insulating oil. The second heating unit is configured to heat the second insulating oil to a preset withstand voltage test temperature. The test unit is configured to perform a withstand voltage test on the accelerated thermal aging processed sample in the heated second insulating oil according to a preset initial voltage, voltage duration and voltage increasing gradient. The first determining unit is configured to determine the voltage duration of the accelerated thermal aging processed sample when the accelerated thermal aging processed sample is broken down in the withstand voltage test. The evaluation unit is configured to evaluate the insulation life of the to-be-evaluated oil-paper based on the voltage duration of the accelerated thermal aging processed sample. The test unit includes a first applying unit, a second holding unit and a voltage increasing unit; wherein: The first applying unit is configured to apply the initial voltage to the accelerated thermal aging processed sample in the heated second insulating oil. The second holding unit is configured to maintain the current applied voltage for the voltage duration. The voltage boosting unit is configured to boost the accelerated thermal aging processed sample according to the voltage boosting gradient in a unit time length on the basis of a current applied voltage, trigger the second holding unit, and break down the accelerated thermal aging processed sample. The voltage endurance test temperature includes a plurality of different temperatures, and the voltage endurance test duration includes a plurality of different durations. The evaluation unit is further configured to: Determine the AC breakdown field strength of the oil-paper sample and the accelerated thermal aging processed sample in each voltage endurance test, respectively. Based on the test data of each voltage endurance test, fit all unknown coefficients in the predefined insulation life evaluation model. The test data includes the voltage endurance test temperature and the AC breakdown field strength. Use the insulation life evaluation model with all unknown coefficients fitted to evaluate the oil-paper insulation life.

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