Method for detecting mineral oil content in insulating liquid

Abstract

The invention discloses a method for detecting mineral oil content in insulating liquid, which comprises the following steps: S1, acquiring infrared spectrum data information of the insulating liquid with known mineral oil content, establishing a standard curve by using the peak height of a characteristic peak at 2359 + / -2cm <-1 >, and fitting to obtain a linear regression equation; and S2, acquiring infrared spectrum data information of the insulating liquid test sample, and substituting peak height data of a characteristic peak of the insulating liquid test sample at 2359 + / -2cm <-1 > into the linear regression equation for calculation to obtain the mineral oil content in the insulating liquid test sample. The method for detecting the content of the mineral oil in the insulating liquid, which is established by utilizing an infrared spectrometer, particularly a Fourier transform infrared spectrometer (FTIR), has the advantages of simplicity, convenience and rapidness in operation, high accuracy, high precision, high resolution and the like, and can be used for rapidly and nondestructively detecting the content of the mineral oil in the insulating liquid.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment detection, and more specifically, to a method for detecting the content of mineral oil in insulating liquid. Background Art

[0002] Liquid-immersed transformers, also known as oil-immersed transformers, are a common type of power transformers, whose core components such as iron cores and windings are immersed in insulating liquid. Mineral oil, as a commonly used insulating liquid for liquid-immersed transformers, has the advantages of excellent dielectric properties, low price, and high cooling performance. However, its low ignition point leads to poor fire resistance. It is not only non-renewable, but also difficult to biodegrade, especially after leakage, it will cause harm to the environment. Synthetic esters generated by esterification reaction of polyols and acids not only have good insulation and cooling properties, but also have the advantages of high ignition point, moisture resistance, environmental protection and easy degradation, non-toxic and harmless, and long replacement cycle. They can be used as insulating liquids for immersed transformers. Therefore, in order to improve some of its own characteristics including fire resistance, liquid-immersed transformers will replace mineral oil with synthetic esters. However, in the process of replacing mineral oil with synthetic esters, it is inevitable that a certain amount of original mineral oil will remain in the insulating liquid of the liquid-immersed transformer, and detecting the content of residual mineral oil in the insulating liquid is crucial to ensure the effectiveness of the newly filled insulating liquid and evaluate the overall condition of the liquid-immersed transformer. There is currently no good method for detecting the mineral oil content in the insulating fluid of liquid-immersed transformers.

[0003] Therefore, it is of great significance to develop a new method for detecting the mineral oil content in insulating fluid. Summary of the invention

[0004] The purpose of the present invention is to provide a method for detecting the mineral oil content in insulating liquid.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a method for detecting the content of mineral oil in an insulating liquid, comprising:

[0007] S1. Collect infrared spectrum data of insulating liquid with known mineral oil content, using 2359±2cm -1 A standard curve was established based on the peak height of the characteristic peak at , and a linear regression equation was obtained by fitting;

[0008] S2. Collect infrared spectrum data of the insulating liquid test sample and measure the insulating liquid test sample at 2359±2cm -1 The peak height data of the characteristic peak at is substituted into the linear regression equation for calculation to obtain the mineral oil content in the insulating liquid test sample.

[0009] The invention discloses a method for detecting the content of mineral oil in insulating liquid by using an infrared spectrometer, particularly a Fourier transform infrared spectrometer (FTIR), which has the advantages of simple and fast operation, high accuracy, high precision and high resolution, and can detect the content of mineral oil in insulating liquid quickly and non-destructively.

[0010] The present invention selects the infrared spectrum at 2359±2cm -1 The peak height of the characteristic peak at 2359±2cm is used as the quantitative basis for the mineral oil content in the insulating liquid because as the mineral oil content in the insulating liquid increases, -1 The peak height of the characteristic peak at 2359±2cm -1 The R value of the linear regression equation obtained by fitting the standard curve established based on the peak height of the characteristic peak at 2 The value is very close to 1, and the accuracy and precision of the established detection method are high.

[0011] The method for detecting the mineral oil content in the insulating liquid of the present invention can provide an effective tool for power companies to monitor the content of mineral oil in the insulating liquid inside the liquid-immersed transformer after the mineral oil is replaced with synthetic ester in the liquid-immersed transformer, which can help the power companies to adjust the maintenance strategy in time and ensure the safe and stable operation of the power grid.

[0012] Preferably, the infrared spectrum data information includes an infrared spectrum graph, wherein the infrared spectrum graph is expressed in wave numbers (cm -1 ) is the horizontal axis and absorbance is the vertical axis.

[0013] In the present invention, the instrument for collecting the infrared spectrum data information of the insulating liquid includes but is not limited to an infrared spectrometer such as a Fourier transform infrared spectrometer (FTIR); the Fourier transform infrared spectrometer (FTIR) adopts an attenuated total reflection method; the measurement band of the Fourier transform infrared spectrometer (FTIR) is a mid-infrared band, and the wave number range is 400cm -1 -4000cm -1 ; The resolution of the Fourier transform infrared spectrometer (FTIR) is ≤8cm -1 , specifically 4cm -1 ; The scanning number of the Fourier transform infrared spectrometer (FTIR) is ≥16 times, specifically 32 times.

[0014] Preferably, in step S1, the horizontal coordinate of the standard curve is the mass percentage of mineral oil in the insulating liquid, and the vertical coordinate is 2359±2cm -1 The height of the characteristic peak at.

[0015] In the present invention, the mineral oil content in the insulating liquid refers to the mass percentage of the mineral oil in the insulating liquid.

[0016] Preferably, the insulating liquid includes at least one of synthetic ester and mineral oil.

[0017] More preferably, the insulating liquid comprises synthetic ester and mineral oil, and the mass percentage of the mineral oil in the insulating liquid is 0-20%, specifically 0-10%.

[0018] More preferably, the synthetic ester is KI50EX, which is a transformer oil produced by the Lubricant Branch of PetroChina Co., Ltd.

[0019] More preferably, the mineral oil is KI25X, which is KI25X transformer oil produced by the Lubricant Branch of PetroChina Co., Ltd., also known as 25# transformer oil.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention discloses a method for detecting the content of mineral oil in insulating liquid by using an infrared spectrometer, particularly a Fourier transform infrared spectrometer (FTIR), which has the advantages of simple and fast operation, high accuracy, high precision and high resolution, and can detect the content of mineral oil in insulating liquid quickly and non-destructively.

[0022] The present invention selects the infrared spectrum at 2359±2cm -1 The peak height of the characteristic peak at 2359±2cm is used as the quantitative basis for the mineral oil content in the insulating liquid because as the mineral oil content in the insulating liquid increases, -1 The peak height of the characteristic peak at 2359±2cm -1 The R value of the linear regression equation obtained by fitting the standard curve established based on the peak height of the characteristic peak at 2 The value is very close to 1, and the accuracy and precision of the established detection method are high.

[0023] The method for detecting the mineral oil content in the insulating liquid of the present invention can provide an effective tool for power companies to monitor the content of mineral oil in the insulating liquid inside the liquid-immersed transformer after the mineral oil is replaced with synthetic ester in the liquid-immersed transformer, which can help the power companies to adjust the maintenance strategy in time and ensure the safe and stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the infrared spectra of the insulating liquid with different mineral oil mass percentages in Example 1.

[0025] Figure 2 This is the infrared spectrum of the insulating liquid in Example 1 with a mineral oil mass percentage of 0%.

[0026] Figure 3This is the infrared spectrum of the insulating liquid with a mineral oil mass percentage of 4% in Example 1.

[0027] Figure 4 This is the infrared spectrum of the insulating liquid with a mineral oil mass percentage of 6% in Example 1.

[0028] Figure 5 This is the infrared spectrum of the insulating liquid with a mineral oil mass percentage of 8% in Example 1.

[0029] Figure 6 This is the infrared spectrum of the insulating liquid with a mineral oil mass percentage of 10% in Example 1.

[0030] Figure 7 This is the standard curve diagram of Example 1.

[0031] Figure 8 This is an infrared spectrum of the insulating liquid test sample of Example 1 (insulating liquid with a mineral oil mass percentage of 5%).

[0032] Fig. 9 This is the infrared spectra of the insulating liquid with different mineral oil mass percentages in Comparative Example 1.

[0033] Fig.10 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 0%.

[0034] Fig.11 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 1.5%.

[0035] Fig.12 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 2.5%.

[0036] Fig.13 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 3.5%.

[0037] Fig.14 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 4.5%.

[0038] Fig.15 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 5.5%.

[0039] Fig.16 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 7.5%.

[0040] Fig.17 This is the infrared spectrum of the insulating liquid in comparative example 1 with a mineral oil mass percentage of 10%.

[0041] Fig.18 This is the standard curve diagram of Comparative Example 1.

[0042] Fig.19 This is the standard curve diagram of Comparative Example 2.

[0043] Fig. 20 This is the standard curve diagram of Comparative Example 3.

[0044] Fig.21 This is the standard curve diagram of Comparative Example 4.

[0045] Fig. 22 This is the standard curve diagram of Comparative Example 5. DETAILED DESCRIPTION

[0046] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0047] The experimental methods in the following examples without specifying specific conditions are generally carried out according to conventional conditions in the art or according to conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets.

[0048] In each embodiment and comparative example of the present invention, the use of reagents is as follows:

[0049] Synthetic ester, KI50EX, KI50EX transformer oil produced by Lubricant Branch of PetroChina Co., Ltd.;

[0050] Mineral oil, KI25X, KI25X transformer oil produced by the Lubricant Branch of China National Petroleum Corporation, also known as 25# transformer oil.

[0051] In the present invention, the mineral oil content in the insulating liquid refers to the mass percentage of the mineral oil in the insulating liquid.

[0052] Example 1

[0053] This embodiment provides a method for detecting the mineral oil content in an insulating liquid, comprising:

[0054] S1. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 4%, 6%, 8%, and 10%, and use them as insulating liquids with known mineral oil content for standby use;

[0055] S2. Using Fourier transform infrared spectrometer (FTIR), attenuated total reflection method, the measurement band is mid-infrared band (wave number range is 400cm -1 -4000cm -1 ), resolution is 4cm-1 Under the condition of 32 scans, the infrared spectrum data information of five insulating liquids with known mineral oil content prepared in step S1 was collected [in wave number (cm -1 ) as the horizontal axis and absorbance as the vertical axis, such as Figure 1-6 As shown], read 2359cm -1 The peak height of the characteristic peak at , the experiment was repeated 3 times and the average value was taken;

[0056] S3. Take the mass percentage of mineral oil in the insulating liquid as the horizontal axis, 2359cm -1 The standard curve is established with the peak height of the characteristic peak as the ordinate (such as Figure 7 As shown), and the linear regression equation (y=-0.0148x+0.1634, R 2 =0.9925);

[0057] S4. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare an insulating liquid with a mineral oil mass percentage of 5%, and use this as an insulating liquid test sample for standby use;

[0058] S5. Using Fourier transform infrared spectrometer (FTIR), attenuated total reflection method, the measurement band is mid-infrared band (wave number range is 400cm -1 -4000cm -1 ), resolution is 4cm -1 , the infrared spectrum data information of the insulating liquid test sample (insulating liquid with a mineral oil mass percentage of 5%) in step S4 is collected under the condition that the number of scans is 32 times [in wave number (cm -1 ) as the horizontal axis and absorbance as the vertical axis, such as Figure 8 As shown], read 2359cm -1 The experiment was repeated 3 times and the average value was taken. Then the average value of the peak height was substituted into the linear regression equation (y = -0.0148x + 0.1634, R 2 =0.9925), the calculated mineral oil mass percentage of the insulating liquid test sample is 4.71%, with an error of -5.8%.

[0059] Comparative Example 1

[0060] This comparative example provides a method for detecting the mineral oil content in an insulating liquid. The difference between this method and Example 1 is that the infrared spectrum is selected at 2700-3100 cm -1 The peak area of ​​the band is used as the quantitative basis for the mineral oil content in the insulating liquid, 2700-3100cm -1 The band is the range of the stretching vibration characteristic peaks corresponding to the methyl and methylene functional groups, as shown below:

[0061] S1. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 1.5%, 2.5%, 3.5%, 4.5%, 5.5%, 7.5%, and 10%, and use them as insulating liquids with known mineral oil content for standby use;

[0062] S2. Using Fourier transform infrared spectrometer (FTIR), attenuated total reflection method, the measurement band is mid-infrared band (wave number range is 400cm -1 -4000cm -1 ), resolution is 4cm -1 Under the condition of 32 scans, the infrared spectrum data information of eight insulating liquids with known mineral oil content prepared in step S1 was collected [in wave number (cm -1 ) as the horizontal axis and absorbance as the vertical axis, such as Figure 9-17 As shown], read 2700-3100cm -1 The peak area of ​​the band, the experiment was repeated 3 times and the average value was taken;

[0063] S3. Take the mass percentage of mineral oil in the insulating liquid as the horizontal axis, 2700-3100cm -1 The peak area of ​​the band is used as the ordinate to establish a standard curve (such as Fig.18 As shown), and the linear regression equation (y=1.0709x+12.586, R 2 =0.9685).

[0064] Comparative Example 2

[0065] This comparative example provides a method for detecting the mineral oil content in an insulating liquid. The difference between this method and Example 1 is that the infrared spectrum is selected at 1460 cm -1 The peak area of ​​the characteristic peak at 1460cm is used as the quantitative basis for the mineral oil content in the insulating liquid. -1 It is the methylene deformation vibration absorption peak, as shown below:

[0066] S1. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 1.5%, 2.5%, 3.5%, 4.5%, 5.5%, 7.5%, and 10%, and use them as insulating liquids with known mineral oil content for standby use;

[0067] S2. Using Fourier transform infrared spectrometer (FTIR), attenuated total reflection method, the measurement band is mid-infrared band (wave number range is 400cm -1 -4000cm-1 ), resolution is 4cm -1 Under the condition of 32 scans, the infrared spectrum data information of eight insulating liquids with known mineral oil content prepared in step S1 was collected [in wave number (cm -1 ) as the abscissa and absorbance as the ordinate], reading 1460cm -1 The peak area of ​​the characteristic peak at , the experiment was repeated 3 times and the average value was taken;

[0068] S3. Take the mass percentage of mineral oil in the insulating liquid as the horizontal axis, 1460cm -1 The peak area of ​​the characteristic peak at is used as the ordinate to establish a standard curve (such as Fig.19 As shown), and the linear regression equation (y=0.115x+2.0351, R 2 =0.9414).

[0069] Comparative Example 3

[0070] This comparative example provides a method for detecting the content of mineral oil in an insulating liquid. The difference between this method and Example 1 is that the infrared spectrum is selected at 2359 cm -1 The peak area of ​​the characteristic peak at is used as the quantitative basis for the mineral oil content in the insulating liquid, as shown below:

[0071] S1. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 4%, 6%, 8%, and 10%, and use them as insulating liquids with known mineral oil content for standby use;

[0072] S2. Using Fourier transform infrared spectrometer (FTIR), attenuated total reflection method, the measurement band is mid-infrared band (wave number range is 400cm -1 -4000cm -1 ), resolution is 4cm -1 Under the condition of 32 scans, the infrared spectrum data information of five insulating liquids with known mineral oil content prepared in step S1 was collected [in wave number (cm -1 ) as the horizontal axis and absorbance as the vertical axis, such as Figure 1-6 As shown], read 2359cm -1 The peak area of ​​the characteristic peak at , the experiment was repeated 3 times and the average value was taken;

[0073] S3. Take the mass percentage of mineral oil in the insulating liquid as the horizontal axis, 2359cm -1 The peak area of ​​the characteristic peak at is used as the ordinate to establish a standard curve (such as Fig. 20As shown), and the linear regression equation (y = -0.6631x + 9.3509, R 2 =0.9293).

[0074] Comparative Example 4

[0075] This comparative example provides a method for detecting the content of mineral oil in an insulating liquid. The difference between the comparative example and the example 1 is that the open flash point of the insulating liquid is selected as the quantitative basis for the content of mineral oil in the insulating liquid. The specific method is as follows:

[0076] S1. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 2.5%, 4.5%, 7.5%, and 10%, and use them as insulating liquids with known mineral oil content for standby use;

[0077] S2. According to GB / T 3536-2008 standard, the open flash points of 5 kinds of insulating liquids with known mineral oil content were tested respectively. The experiment was repeated 3 times and the average value was taken. A standard curve was established with the mass percentage of mineral oil in the insulating liquid as the horizontal axis and the open flash point as the vertical axis (such as Fig.21 As shown), and the linear regression equation (y = -7.5866x + 265.91, R 2 =0.9210).

[0078] Comparative Example 5

[0079] This comparative example provides a method for detecting the content of mineral oil in an insulating liquid. The difference between the comparative example and the example 1 is that the closed cup flash point of the insulating liquid is selected as the quantitative basis for the content of mineral oil in the insulating liquid. The specific method is as follows:

[0080] S1. Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 2.5%, 4.5%, 7.5%, and 10%, and use them as insulating liquids with known mineral oil content for standby use;

[0081] S2. According to GB / T 261-2021 standard, the closed cup flash points of 5 insulating liquids with known mineral oil content were tested respectively. The experiment was repeated 3 times and the average value was taken. A standard curve was established with the mass percentage of mineral oil in the insulating liquid as the horizontal axis and the closed cup flash point as the vertical axis (such as Fig. 22 As shown), and the linear regression equation (y = -8.1643x + 251.3, R 2 =0.9593).

[0082] By integrating the linear regression equation information of Example 1 and Comparative Examples 1-5, the following table can be obtained:

[0083] Table 1

[0084] Quantitative basis for mineral oil content Linear regression equation <![CDATA[R 2 ]]> Example 1 <![CDATA[2359cm -1 The peak height of the characteristic peak at]]> y=-0.0148x+0.1634 0.9925 Comparative Example 1 <![CDATA[2700-3100cm -1 Peak area of ​​the band]]> y=1.0709x+12.586 0.9685 Comparative Example 2 <![CDATA[1460cm -1 The peak area of ​​the characteristic peak at y=0.115x+2.0351 0.9414 Comparative Example 3 <![CDATA[2359cm -1 The peak area of ​​the characteristic peak at y=-0.6631x+9.3509 0.9293 Comparative Example 4 Opening flash point y=-7.5866x+265.91 0.9210 Comparative Example 5 Closed Flash Point y=-8.1643x+251.3 0.9593

[0085] As can be seen from Table 1, only Example 1 uses 2359 cm -1 When the peak height of the characteristic peak at is used as the quantitative basis for the mineral oil content in the insulating fluid, the R 2 The value is closest to 1, which indicates that the detection method established by the present invention is most suitable for the detection of mineral oil content in insulating liquid.

[0086] Performance Testing

[0087] 1. Accuracy and precision test

[0088] (1) Using synthetic ester (KI50EX) as solvent and mineral oil (KI25X) as solute, prepare insulating liquids with mineral oil mass percentages of 0%, 4%, 5%, 6%, 8%, and 10% respectively for standby use;

[0089] (2) A Fourier transform infrared spectrometer (FTIR) was used with the attenuated total reflection method in the mid-infrared band (wave number range of 400 cm -1 -4000cm -1 ), resolution is 4cm -1 , the number of scans was 32 times, and the infrared spectrum data information of the six insulating liquids in step (1) was collected [in wave number (cm -1 ) as the abscissa and absorbance as the ordinate], reading 2359cm -1 The experiment was repeated 6 times and the average value was taken. Then the average value of the peak height was substituted into the linear regression equation (y = -0.0148x + 0.1634, R 2 =0.9925), and calculate the relative error, standard deviation (SD), and relative standard deviation (RSD) of the six insulating liquids;

[0090] The experimental results are shown in the following table:

[0091] Table 2

[0092] Mineral oil mass percentage / % Relative error / % SD RSD / % 0 / 0.00076 0.5 4 -4.8 0.00091 0.9 5 -6.6 0.00024 0.3 6 -4.3 0.00091 1.2 8 -2.8 0.00100 2.1 10 4.7 0.00024 2.9

[0093] It can be seen from Table 2 that the relative error range of the detection method of the mineral oil content in the insulating liquid of the present invention is small, indicating that the detection method of the present invention has high accuracy.

[0094] The standard deviation (SD) of the detection method of the mineral oil content in the insulating liquid of the present invention is in the range of 0.00024-0.00100, and the relative standard deviation (RSD) is in the range of 0.3-2.9%, indicating that the detection method of the present invention has high precision.

[0095] It can be seen from this that the method for detecting the mineral oil content in the insulating liquid established by the present invention using an infrared spectrometer, especially a Fourier transform infrared spectrometer (FTIR), has the advantages of simple and fast operation, high accuracy, high precision and high resolution, and can quickly and non-destructively detect the mineral oil content in the insulating liquid.

[0096] The method for detecting the mineral oil content in the insulating liquid of the present invention can provide an effective tool for power companies to monitor the content of mineral oil in the insulating liquid inside the liquid-immersed transformer after the mineral oil is replaced with synthetic ester in the liquid-immersed transformer, which can help the power companies to adjust the maintenance strategy in time and ensure the safe and stable operation of the power grid.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for detecting the content of mineral oil in an insulating liquid, characterized in that: include: S1. Collect infrared spectrum data of insulating liquid with known mineral oil content, using 2359±2cm -1 A standard curve was established based on the peak height of the characteristic peak at , and a linear regression equation was obtained by fitting; S2. Collect infrared spectrum data of the insulating liquid test sample and measure the insulating liquid test sample at 2359±2cm -1 The peak height data of the characteristic peak at is substituted into the linear regression equation for calculation to obtain the mineral oil content in the insulating liquid test sample.

2. The method for detecting the mineral oil content in the insulating liquid according to claim 1, characterized in that: The insulating liquid includes at least one of synthetic ester and mineral oil.

3. The method for detecting the mineral oil content in the insulating liquid according to claim 2, characterized in that: The insulating liquid comprises synthetic ester and mineral oil, and the mass percentage of the mineral oil in the insulating liquid is 0-20%.

4. The method for detecting the mineral oil content in the insulating liquid according to claim 3, characterized in that: The mass percentage of mineral oil in the insulating liquid is 0-10%.

5. The method for detecting the mineral oil content in the insulating liquid according to claim 2, characterized in that: The synthetic ester is KI50EX.

6. The method for detecting the mineral oil content in the insulating liquid according to claim 2, characterized in that: The mineral oil is KI25X.

7. The method for detecting the mineral oil content in the insulating liquid according to claim 1, characterized in that: The infrared spectrum data information includes an infrared spectrum graph, and the infrared spectrum graph uses wave number as the horizontal axis and absorbance as the vertical axis.

8. The method for detecting the mineral oil content in the insulating liquid according to claim 1, characterized in that: In step S1, the horizontal coordinate of the standard curve is the mass percentage of mineral oil in the insulating liquid, and the vertical coordinate is 2359±2cm -1 The height of the characteristic peak.

9. The method for detecting the mineral oil content in the insulating liquid according to claim 1, characterized in that: The instrument for collecting the infrared spectrum data information of the insulating liquid is a Fourier transform infrared spectrometer.

10. The method for detecting the mineral oil content in the insulating liquid according to claim 9, characterized in that: The Fourier transform infrared spectrometer adopts the attenuated total reflection method; the measurement band of the Fourier transform infrared spectrometer is the mid-infrared band, and the wave number range is 400cm -1 -4000cm -1 ; The resolution of the Fourier transform infrared spectrometer is ≤8cm -1 ; The scanning number of the Fourier transform infrared spectrometer is ≥16 times.

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