An anti-aging compounded insulating oil and oil-paper insulation system, and a preparation method and application thereof

Abstract

The present application relates to an anti-aging compound insulating oil and oil-paper insulation system and its preparation method and application, belong to transformer insulation technical field. The present application provides a kind of compound insulating oil, the compound insulating oil contains electrical insulating oil and compound additive;The electrical insulating oil includes at least one of mineral insulating oil, synthetic insulating oil and natural ester insulating oil, and the compound additive contains at least two of carbonic acid dioctyl ester, carbonic acid dinonyl ester and carbonic acid didecyl ester.The present application improves the aging insulating paper polymerization degree, reduces the water content and acid value of aging insulating oil, improves the anti-aging performance of oil-paper insulation system, prolongs its service life, and provides continuous and efficient protection for oil-paper insulation in actual long-term operation, in line with the operation concept of green and low carbon power grid.

Description

Technical Field

[0001] This invention relates to the field of transformer insulation technology, and in particular to an anti-aging composite insulating oil and oil-paper insulation system, its preparation method and application. Background Technology

[0002] With societal development, people have placed higher demands on the environmental friendliness and renewability of insulating oils. In recent years, the application of ester-based insulating oils in transformers has been increasing. Currently, the main environmentally friendly ester-based insulating oils used are natural ester insulating oils and synthetic ester insulating oils. As a liquid insulating medium, ester-based oils undergo complex interactions with the oil-paper insulation system composed of cellulose insulating paper during operation. Ester-based oil molecules have high polarity and strong hygroscopicity, enabling them to quickly absorb free moisture from the insulating paper, reducing the water activity of cellulose and thus inhibiting the hydrolysis reaction of cellulose, protecting the insulating paper. However, during long-term operation, ester-based oils undergo oxidative decomposition, and the synergistic effect of oxidation products and acidic substances accelerates the aging of the insulating paper. Common technologies currently address this by treating the insulating paper, using acid-resistant insulating paper to enhance its hydrolysis resistance, or coating the surface of the insulating paper with nanomaterial fillers to block the penetration of acidic substances.

[0003] Current technologies for treating insulating paper are complex and costly. Methods using nanomaterials as fillers to coat the surface of insulating paper have a short lifespan, with the coating eventually peeling off and nanoparticles remaining in the insulating oil further reducing the lifespan of the oil-paper insulation system. Furthermore, for operating transformers, it is difficult to remove the insulating paper for reprocessing, making methods for modifying the insulating paper difficult to implement. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an anti-aging compound insulating oil and oil-paper insulation system, its preparation method and application.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a compound insulating oil comprising an electrical insulating oil and a compound additive; the electrical insulating oil comprising at least one of mineral insulating oil, synthetic insulating oil and natural ester insulating oil, and the compound additive comprising at least two of dioctyl carbonate, dinonyl carbonate and didecyl carbonate.

[0006] This invention significantly improves the anti-aging properties of the oil-paper insulation system and extends its service life by adding at least two of the following components to the electrical insulating oil: dioctyl carbonate, dinonyl carbonate, and didecyl carbonate.

[0007] As a preferred embodiment of the compound insulating oil of the present invention, the synthetic insulating oil includes Midel7131 synthetic ester insulating oil, and the natural ester insulating oil includes FR3 natural ester insulating oil.

[0008] As a preferred embodiment of the compound insulating oil of the present invention, the mass concentration of the compound additive in the compound insulating oil is preferably 0.1% to 1%, for example, including but not limited to any point value or any range of two points from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% and 1%.

[0009] As a preferred embodiment of the compound insulating oil of the present invention, the compound additive contains dioctyl carbonate, and the mass ratio of dioctyl carbonate to total compound additive is preferably dioctyl carbonate: total compound additive = (1~2):3, for example including but not limited to any point value or any range value composed of any two points in 1:3, 1.2:3, 1.5:3, 1.8:3 and 2:3.

[0010] As a preferred embodiment of the compound insulating oil of the present invention, the compound additive contains dioctyl carbonate and dinonyl carbonate, and the mass ratio of dioctyl carbonate to dinonyl carbonate is preferably dioctyl carbonate: dinonyl carbonate = (1~2):1, for example, including but not limited to any point value or any range value composed of any two points such as 1:1, 1.2:1, 1.5:1, 1.8:1 and 2:1.

[0011] As a preferred embodiment of the compound insulating oil of the present invention, the compound additive contains dioctyl carbonate and didecyl carbonate, and the mass ratio of dioctyl carbonate to didecyl carbonate is preferably dioctyl carbonate: didecyl carbonate = (1~2):1, for example, including but not limited to any point value or any range value composed of any two points such as 1:1, 1.2:1, 1.5:1, 1.8:1 and 2:1.

[0012] As a preferred embodiment of the compound insulating oil of the present invention, the compound additive contains dioctyl carbonate, dinonyl carbonate and didecyl carbonate, and the mass ratio of dioctyl carbonate, dinonyl carbonate and didecyl carbonate is preferably dioctyl carbonate: dinonyl carbonate: didecyl carbonate = (1~2): 1:1, for example, including but not limited to any point value or any range value composed of any two points in 1:1:1, 1.2:1:1, 1.5:1:1, 1.8:1:1 and 2:1:1.

[0013] Secondly, the present invention provides an anti-aging oil-paper insulation system, wherein the anti-aging oil-paper insulation system contains the aforementioned compound insulating oil and insulating paper.

[0014] As a preferred embodiment of the anti-aging oil paper insulation system of the present invention, the insulating paper includes at least one of plant fiber insulating paper, synthetic fiber insulating paper and ceramic fiber insulating paper.

[0015] As a preferred embodiment of the anti-aging oil-paper insulation system of the present invention, the mass ratio of the compound insulating oil to the insulating paper is preferably 8~12:1, including but not limited to any point value or any range value composed of any two points such as 8:1, 9:1, 10:1, 11:1 and 12:1.

[0016] Thirdly, the present invention provides a method for preparing the anti-aging oil-paper insulation system, wherein the compound insulating oil and insulating paper are mixed, and the mass ratio of the compound insulating oil to the insulating paper is preferably 8~12:1, for example including but not limited to any point value or any range value composed of any two points in 8:1, 9:1, 10:1, 11:1 and 12:1.

[0017] As a preferred embodiment of the preparation method of the anti-aging oil-paper insulation system of the present invention, the electrical insulating oil and the compound additives are stirred and mixed for 5-10 hours to obtain the compound insulating oil, preferably stirred and mixed for 7 hours.

[0018] As a preferred embodiment of the preparation method of the anti-aging oil-paper insulation system of the present invention, the compound insulating oil and cellulose insulating paperboard are dried at 80~95℃ and 40~70 Pa vacuum conditions for 1~2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard; the dried cellulose insulating paperboard is immersed in the dried compound insulating oil and dried at 40~70℃ vacuum for 1~2 days to obtain the anti-aging oil-paper insulation system.

[0019] As a more preferred embodiment of the preparation method of the anti-aging oil-paper insulation system of the present invention, the compound insulating oil and cellulose insulating paperboard are dried at 90°C and 50 Pa vacuum conditions for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard; the dried cellulose insulating paperboard is immersed in the dried compound insulating oil and dried at 60°C vacuum for 1 day to obtain the anti-aging oil-paper insulation system.

[0020] Fourthly, the present invention provides the application of the aforementioned compound insulating oil in the preparation of an anti-aging oil-paper insulation system.

[0021] The anti-aging oil-paper insulation system prepared by this invention can reduce the degree of polymerization decline of the insulation paper, delay the increase of water content in the insulation oil, and reduce the acid value of the insulation oil.

[0022] Fifthly, the present invention provides a method for improving the anti-aging performance of an oil-paper insulation system by mixing the compounded insulating oil and insulating paper to obtain an anti-aging oil-paper insulation system.

[0023] As a preferred embodiment of the method for improving the anti-aging performance of the oil-paper insulation system according to the present invention, the mass ratio of the compound insulating oil to the insulating paper is preferably 8~12:1, for example, including but not limited to any point value or any range value composed of any two points such as 8:1, 9:1, 10:1, 11:1 and 12:1.

[0024] As a preferred embodiment of the method for improving the anti-aging performance of the oil-paper insulation system according to the present invention, the electrical insulating oil and the compound additives are stirred and mixed for 5 to 10 hours to obtain a compound insulating oil, preferably stirred and mixed for 7 hours.

[0025] As a preferred embodiment of the method for improving the anti-aging performance of the oil-paper insulation system according to the present invention, the compound insulating oil and cellulose insulating paperboard are dried at 80~95℃ and 40~70 Pa vacuum conditions for 1~2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard; the dried cellulose insulating paperboard is immersed in the dried compound insulating oil and vacuum dried at 40~70℃ for 1~2 days to obtain the anti-aging oil-paper insulation system.

[0026] As a more preferred embodiment of the method for improving the anti-aging performance of the oil-paper insulation system according to the present invention, the compound insulating oil and cellulose insulating paperboard are dried at 90°C and 50 Pa vacuum conditions for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard; the dried cellulose insulating paperboard is immersed in the dried compound insulating oil and dried at 60°C vacuum for 1 day to obtain the anti-aging oil-paper insulation system.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention improves the polymerization degree of aging insulating paper and reduces the water content and acid value of aging insulating oil by adding at least two of the following components: dioctyl carbonate, dinonyl carbonate, and didecyl carbonate to electrical insulating oil. This enhances the anti-aging performance of the oil-paper insulation system and extends its service life. The oil-paper insulation provides continuous and efficient protection in actual long-term operation, which is in line with the green and low-carbon operation concept of the power grid. Detailed Implementation

[0028] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Unless otherwise specified, other materials and reagents used in the embodiments are commercially available.

[0029] Example 1 Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and dinonyl carbonate.

[0030] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to dinonyl carbonate is 1:1.

[0031] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0032] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0033] Example 2 The difference from Example 1 is that the compound additives are dioctyl carbonate and didecyl carbonate, with a mass ratio of 1:1.

[0034] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and didecyl carbonate.

[0035] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to didecyl carbonate is 1:1.

[0036] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0037] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0038] Example 3 The difference from Example 1 is that the compound additives are dinonyl carbonate and didecyl carbonate, with a mass ratio of dinonyl carbonate to didecyl carbonate of 1:1.

[0039] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dinonyl carbonate and didecyl carbonate.

[0040] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dinonyl carbonate to didecyl carbonate is 1:1.

[0041] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0042] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0043] Example 4 The difference from Example 1 is that the compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate, and the mass ratio of dioctyl carbonate, dinonyl carbonate and didecyl carbonate is 1:1:1.

[0044] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate.

[0045] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate, dinonyl carbonate, and didecyl carbonate is 1:1:1.

[0046] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0047] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0048] Example 5 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil.

[0049] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and dinonyl carbonate.

[0050] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dioctyl carbonate to dinonyl carbonate is 1:1.

[0051] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0052] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0053] Example 6 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dioctyl carbonate and didecyl carbonate, with a mass ratio of dioctyl carbonate to didecyl carbonate of 1:1.

[0054] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and didecyl carbonate.

[0055] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dioctyl carbonate to didecyl carbonate is 1:1.

[0056] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0057] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0058] Example 7 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dinonyl carbonate and didecyl carbonate, with a mass ratio of dinonyl carbonate to didecyl carbonate of 1:1.

[0059] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dinonyl carbonate and didecyl carbonate.

[0060] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dinonyl carbonate to didecyl carbonate is 1:1.

[0061] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0062] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0063] Example 8 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate, with a mass ratio of 1:1:1.

[0064] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate.

[0065] Midel7131 synthetic ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate, dinonyl carbonate, and didecyl carbonate is 1:1:1.

[0066] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0067] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0068] Example 9 The difference from Example 1 is that the mass ratio of dioctyl carbonate to dinonyl carbonate is 2:1.

[0069] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and dinonyl carbonate.

[0070] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to dinonyl carbonate is 2:1.

[0071] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0072] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0073] Example 10 The difference from Example 1 is that the mass ratio of dioctyl carbonate to dinonyl carbonate is 1:2.

[0074] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and dinonyl carbonate.

[0075] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to dinonyl carbonate is 1:2.

[0076] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0077] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0078] Example 11 The difference from Example 1 is that the compound additives are dioctyl carbonate and didecyl carbonate, with a mass ratio of 2:1.

[0079] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and didecyl carbonate.

[0080] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to didecyl carbonate is 2:1.

[0081] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0082] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0083] Example 12 The difference from Example 1 is that the compound additives are dioctyl carbonate and didecyl carbonate, with a mass ratio of 1:2.

[0084] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and didecyl carbonate.

[0085] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to didecyl carbonate is 1:2.

[0086] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0087] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0088] Example 13 The difference from Example 1 is that the compound additives are dinonyl carbonate and didecyl carbonate, with a mass ratio of dinonyl carbonate to didecyl carbonate of 2:1.

[0089] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dinonyl carbonate and didecyl carbonate.

[0090] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dinonyl carbonate to didecyl carbonate is 2:1.

[0091] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0092] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0093] Example 14 The difference from Example 1 is that the compound additives are dinonyl carbonate and didecyl carbonate, with a mass ratio of dinonyl carbonate to didecyl carbonate of 1:2.

[0094] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dinonyl carbonate and didecyl carbonate.

[0095] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dinonyl carbonate to didecyl carbonate is 1:2.

[0096] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0097] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0098] Example 15 The difference from Example 1 is that the compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate, and the mass ratio of dioctyl carbonate, dinonyl carbonate and didecyl carbonate is 2:1:1.

[0099] Oil-paper insulation system: FR3 natural ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate.

[0100] FR3 natural ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate, dinonyl carbonate, and didecyl carbonate is 2:1:1.

[0101] At room temperature, FR3 natural ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the FR3 natural ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0102] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0103] Example 16 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the mass ratio of dioctyl carbonate to dinonyl carbonate is 2:1.

[0104] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and dinonyl carbonate.

[0105] Midel7131 synthetic ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to dinonyl carbonate is 2:1.

[0106] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0107] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0108] Example 17 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the mass ratio of dioctyl carbonate to dinonyl carbonate is 1:2.

[0109] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and dinonyl carbonate.

[0110] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dioctyl carbonate to dinonyl carbonate is 1:2.

[0111] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0112] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0113] Example 18 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dioctyl carbonate and didecyl carbonate, with a mass ratio of dioctyl carbonate to didecyl carbonate of 2:1.

[0114] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and didecyl carbonate.

[0115] Midel7131 synthetic ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate to didecyl carbonate is 2:1.

[0116] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0117] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0118] Example 19 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dioctyl carbonate and didecyl carbonate, with a mass ratio of dioctyl carbonate to didecyl carbonate of 1:2.

[0119] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate and didecyl carbonate.

[0120] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dioctyl carbonate to didecyl carbonate is 1:2.

[0121] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0122] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0123] Example 20 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dinonyl carbonate and didecyl carbonate, with a mass ratio of dinonyl carbonate to didecyl carbonate of 2:1.

[0124] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dinonyl carbonate and didecyl carbonate.

[0125] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dinonyl carbonate to didecyl carbonate is 2:1.

[0126] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0127] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0128] Example 21 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dinonyl carbonate and didecyl carbonate, with a mass ratio of dinonyl carbonate to didecyl carbonate of 1:2.

[0129] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dinonyl carbonate and didecyl carbonate.

[0130] Midel7131 synthetic ester insulating oil contains a compound additive with a mass concentration of 0.7%, wherein the mass ratio of dinonyl carbonate to didecyl carbonate is 1:2.

[0131] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0132] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0133] Example 22 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, and the compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate, with a mass ratio of 2:1:1.

[0134] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper; compound additives are dioctyl carbonate, dinonyl carbonate and didecyl carbonate.

[0135] Midel7131 synthetic ester insulating oil contains 0.7% by mass of a compound additive, wherein the mass ratio of dioctyl carbonate, dinonyl carbonate, and didecyl carbonate is 2:1:1.

[0136] At room temperature, the Midel 7131 synthetic ester insulating oil was placed on a magnetic stirrer and stirred thoroughly for 7 hours to ensure that the compounded additives were fully incorporated into the Midel 7131 synthetic ester insulating oil. After dissolution, the oil sample was clear without suspension and the color was slightly darker, thus obtaining the compounded insulating oil.

[0137] The compound insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried compound insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried compound insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0138] Comparative Example 1 The difference from Example 1 is that it does not contain compound additives.

[0139] Oil-paper insulation system: FR3 natural ester insulating oil and cellulose insulating paperboard that meets the technical requirements of international standard IEC60641-2 for electrical paper.

[0140] FR3 natural ester insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried FR3 natural ester insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in dried FR3 natural ester insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain an oil-paper insulation system.

[0141] Comparative Example 2 The difference from Example 1 is that the insulating oil is Midel 7131 synthetic ester insulating oil, which does not contain compound additives.

[0142] Oil-paper insulation system: Midel 7131 synthetic ester insulating oil, and cellulose insulating paperboard that meets the technical requirements for electrical paper in international standard IEC60641-2.

[0143] Midel 7131 synthetic ester insulating oil and cellulose insulating paperboard were dried at 90℃ and 50 Pa vacuum for 2 days to obtain dried Midel 7131 synthetic ester insulating oil and dried cellulose insulating paperboard. The dried cellulose insulating paperboard was then immersed in the dried Midel 7131 synthetic ester insulating oil at a mass ratio of 10:1 and dried at 60℃ vacuum for 1 day to obtain the oil-paper insulation system.

[0144] Test Example 1 According to GB 11026.1-2014 "Guidelines for Determining the Heat Resistance of Electrical Insulation Materials", an oil-paper insulation environment similar to the internal insulation structure of the transformer on site was designed. The oil-paper insulation system was placed in a constant temperature aging chamber at 130℃ for accelerated thermal aging treatment. Samples were taken periodically (for 20, 60, and 100 days) to test the degree of polymerization of the insulating paper, the water content of the insulating oil, and the acid value. The degree of polymerization of the insulating paper was tested according to IEC 60450-2007 "Measurement of the average viscometric degree of polymerization of new and aged cellulosic electrically insulating materials", the water content of the insulating oil was tested according to GB / T 7600-2014 "Determination of Moisture Content in Transformer Oil and Turbine Oil in Operation (Coulometric Method)", and the acid value of the insulating oil was tested according to GB / T 264-1983 "Determination of Acid Value of Petroleum Products". The service life of the oil-paper insulation system was evaluated through electrical characteristic analysis.

[0145] As shown in Tables 1 to 3, when the compound additives contain dioctyl carbonate, the aging degree of the oil-paper insulation system is lower, which significantly improves the lifespan of the oil-paper insulation system.

[0146] As shown in Tables 4 to 6, when the compound additive contains dioctyl carbonate and the content of dioctyl carbonate compound additive is greater than 50%, the aging degree of the oil-paper insulation system is lower, which significantly improves the life of the oil-paper insulation system.

[0147] The initial degree of polymerization of cellulose insulating paperboard is 1321; the initial water content of FR3 synthetic ester insulating oil is 128 mg / kg, and the acid value is 0.05 mg KOH / g; the initial water content of Midel7131 synthetic ester insulating oil is 113 mg / kg, and the acid value is 0.02 mg KOH / g.

[0148] Table 1. Polymerization reduction rate of insulating paper in Examples 1-8 and Comparative Examples 1-2 Table 2. Rate of increase in moisture content of insulating oil in Examples 1-8 and Comparative Examples 1-2 Table 3. Rate of increase in acid value of insulating oil in Examples 1-8 and Comparative Examples 1-2 Table 4. Decrease in degree of polymerization of insulating paper in Examples 9-22 and Comparative Examples 1-2 Table 5. Rate of increase in moisture content of insulating oil in Examples 9-22 and Comparative Examples 1-2 Table 6. Rate of increase in acid value of insulating oil in Examples 9-22 and Comparative Examples 1-2 Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A compound insulating oil, characterized in that, The compound insulating oil contains electrical insulating oil and compound additives; the electrical insulating oil includes at least one of mineral insulating oil, synthetic insulating oil and natural ester insulating oil, and the compound additives contain at least two of dioctyl carbonate, dinonyl carbonate and didecyl carbonate.

2. The compound insulating oil as described in claim 1, characterized in that, The synthetic insulating oil includes Midel 7131 synthetic ester insulating oil, and the natural ester insulating oil includes FR3 natural ester insulating oil.

3. The compound insulating oil as described in claim 2, characterized in that, The mass concentration of the compound additives in the compound insulating oil is 0.1% to 1%.

4. The compound insulating oil as described in claim 1, characterized in that, The compound additive contains dioctyl carbonate and dinonyl carbonate, and the mass ratio of dioctyl carbonate to dinonyl carbonate is: dioctyl carbonate: dinonyl carbonate = (1~2):

1.

5. The compound insulating oil as described in claim 1, characterized in that, The compound additive contains dioctyl carbonate and didecyl carbonate, and the mass ratio of dioctyl carbonate to didecyl carbonate is: dioctyl carbonate: didecyl carbonate = (1~2):

1.

6. The compound insulating oil as described in claim 1, characterized in that, The compound additive contains dioctyl carbonate, dinonyl carbonate, and didecyl carbonate, and the mass ratio of dioctyl carbonate, dinonyl carbonate, and didecyl carbonate is: dioctyl carbonate: dinonyl carbonate: didecyl carbonate = (1~2): 1:

1.

7. An anti-aging oil-paper insulation system, characterized in that, The anti-aging oil-paper insulation system comprises the compound insulating oil and insulating paper as described in any one of claims 1 to 6.

8. The method for preparing the anti-aging oil-paper insulation system according to claim 7, characterized in that, The composite insulating oil and insulating paper according to any one of claims 1 to 6 are mixed, wherein the mass ratio of the composite insulating oil to the insulating paper is: composite insulating oil: insulating paper = (8~12):

1.

9. The use of the compound insulating oil according to any one of claims 1 to 6 in the preparation of an anti-aging oil-paper insulation system.

10. A method for improving the anti-aging properties of an oil-paper insulation system, characterized in that, The compound insulating oil described in any one of claims 1 to 6 is mixed with insulating paper to obtain an anti-aging oil-paper insulation system.

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