Oil-resistant, high-temperature-resistant and weather-resistant control cable for oil-immersed transformer

Abstract

The invention relates to the technical field of cables, and particularly discloses an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which structurally comprises a conductor, an insulating layer, a wrapping layer, a shielding layer, an isolation sleeve, an armor layer and an outer sheath which are sequentially arranged from inside to outside, the outer sheath is prepared from the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin; 4-6 parts of a stabilizer; 0.4 to 0.6 part of polyethylene wax; 48-52 parts of a plasticizer; 49 to 53 parts of a flame retardant; 12-15 parts of powdered nitrile rubber; 0.4 to 0.6 part of a lubricant; 0.5-1 part of a coloring agent; the preparation method comprises the following steps: assembling to obtain a to-be-protected cable, and coating the periphery of the to-be-protected cable with the raw materials for the outer sheath to obtain a product. The product provided by the invention has high and low temperature resistance, weather resistance, oil resistance and high flame retardance, can stably operate in a severe environment after being matched with an oil-immersed transformer, and provides guarantee for stable power supply of a power system.

Description

Technical Field

[0001] The present application relates to the technical field of cables, and in particular to an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer. Background Art

[0002] Oil-immersed transformer is a kind of transformer with wide application range and good high temperature resistance and weather resistance. It can operate stably in harsh environment and provide strong guarantee for stable power supply of power system. Due to the high operating temperature of oil-immersed transformer, sometimes even up to 105℃, and its application environment is also relatively wide, and the oil is likely to drip or spray when filling or replacing the transformer oil, causing corrosion to other parts, so the cables matching it need to have a variety of excellent properties, such as good high temperature resistance, high flame retardancy, weather resistance and oil resistance (cycloalkane oil for transformer).

[0003] The original outer sheath of oil-immersed transformer cables is usually made of polyvinyl chloride as the main material, but polyvinyl chloride can only make the maximum operating temperature of the cable reach 70°C. At the same time, polyvinyl chloride has general oil resistance, so it cannot meet the performance requirements of the oil-immersed transformer in the use environment. In addition, its flame retardant effect is not satisfactory. Therefore, some researchers have added stabilizers, flame retardants, plasticizers and other additives to the outer sheath material to improve the heat resistance, flame retardancy and weather resistance of oil-immersed transformer cables. However, with actual use, researchers have found that the operating temperature of oil-immersed transformers can sometimes be as low as minus 40°C. At this time, the outer sheath of oil-immersed transformer cables is very prone to cracking and damage, which seriously affects the service life and application scope of oil-immersed transformer cables. Therefore, the comprehensive performance of oil-resistant, high-temperature and weather-resistant control cables for oil-immersed transformers still has room for further improvement. Summary of the invention

[0004] In order to make the cable for oil-immersed transformer have high and low temperature resistance, weather resistance, oil resistance and high flame retardancy, the present application provides an oil-resistant, high temperature and weather-resistant control cable for oil-immersed transformer.

[0005] In the first aspect, the present application provides an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, comprising the following structure: a conductor, an insulating layer, a winding layer, a shielding layer, an isolation sleeve, an armor layer and an outer sheath arranged in sequence from the inside to the outside, and the raw materials used for the outer sheath include the following components in parts by weight: 100 parts of polyvinyl chloride resin; 4-6 parts of stabilizer; 0.4-0.6 parts of polyethylene wax; 48-52 parts of plasticizer; 49-53 parts of flame retardant; 12-15 parts of powdered nitrile rubber; 0.4-0.6 parts of plasticizer; 0.5-1 parts of colorant.

[0006] Preferably, the raw materials used for the outer sheath include the following components in parts by weight: 100 parts of polyvinyl chloride resin; 5 parts of stabilizer; 0.5 parts of polyethylene wax; 50 parts of plasticizer; 51 parts of flame retardant; 14 parts of powdered nitrile rubber; 0.5 parts of plasticizer; and 0.5 parts of colorant.

[0007] By adopting the above technical scheme, the present application obtains the raw materials used for the outer sheath by compounding multiple substances, and strictly controls the ratio between the components. Multiple substances cooperate with each other and give full play to the synergistic effect between each other. The final outer sheath has excellent oil resistance, heat resistance, flame retardancy, weather resistance and low temperature resistance, and has good anti-migration ability. At a temperature of minus 40°C, the low-temperature tensile elongation of the outer sheath is still not less than 40%, which greatly improves the comprehensive performance of the oil-resistant, high-temperature and weather-resistant control cable for oil-immersed transformers, significantly improves the service life of itself and the oil-immersed transformer, and effectively expands the scope of application. At the same time, all non-metallic raw materials used in this application do not belong to the harmful substances restricted in the use of electronic and electrical equipment, and have certain environmental significance.

[0008] Preferably, the raw material used for the outer sheath further comprises polycarbonate-polydimethylsiloxane block copolymer, and the amount of the polycarbonate-polydimethylsiloxane block copolymer is 15-20wt% of the amount of the polyvinyl chloride resin.

[0009] The polycarbonate-polydimethylsiloxane block copolymer is prepared by the following method: The polycarbonate is dispersed in dioxane and stirred. After the polycarbonate is completely dissolved, ethylene glycol and zinc acetate are added at a certain temperature. After a period of reaction, the reaction solution is washed with deionized water to remove the dioxane and zinc acetate, and the reaction solution is filtered under reduced pressure and dried under vacuum to obtain a white solid. The dioxane aqueous solution is added dropwise to dimethyldichlorosilane, heated and refluxed until the liquid phase is clear, and the organic solvent and small molecular polysiloxane are removed by distillation under reduced pressure. The product is filtered to obtain a clear oily substance. All the white solid, all the clear oily substance and triethylamine are dispersed in dichloromethane, heated and refluxed, and the obtained product is washed with water until neutral, precipitated with alcohol, filtered and dried to obtain a polycarbonate-polydimethylsiloxane block copolymer, wherein the amount ratio of polycarbonate to dimethyldichlorosilane is 5.1:(80-120).

[0010] Preferably, in the preparation process of the polycarbonate-polydimethylsiloxane block copolymer, the amount ratio of polycarbonate to dimethyldichlorosilane is 5.1:(90-100).

[0011] By adopting the above technical scheme, the present application adds a certain amount of polycarbonate-polydimethylsiloxane block copolymer to the raw materials used for the outer sheath. The polycarbonate segment in the main chain has a high polarity and good compatibility with the polyvinyl chloride resin, while the polydimethylsiloxane segment has good low-temperature flexibility. The two form a block copolymer through a certain synthetic route, which can give full play to their respective excellent properties, thereby significantly improving the low-temperature toughness of the outer sheath, and its oil resistance, heat resistance, flame retardancy and weather resistance are still maintained at a high level.

[0012] The present application also strictly controls the amount of polycarbonate-polydimethylsiloxane block copolymer added and the amount ratio of polycarbonate and dimethyldichlorosilane used in the preparation process, so as to balance its toughening effect on the overall system and the uniform compatibility between the components, thereby further improving the low-temperature toughness and other comprehensive properties of the outer sheath.

[0013] Optionally, the plasticizer includes plasticizer DOTP and plasticizer TOTM in a weight ratio of (18-22):30.

[0014] Preferably, the plasticizer comprises plasticizer DOTP and plasticizer TOTM in a weight ratio of 20:30.

[0015] By adopting the above technical scheme, the present application adds a plasticizer DOTP which has good compatibility with polyvinyl chloride resin and has excellent mechanical properties, volatility resistance and electrical properties. The plasticizer TOTM is also added. After compounding with the plasticizer DOTP, it can give the polyvinyl chloride resin good plasticization and special processability, and finally the outer sheath of the cable has excellent electrical insulation and heat resistance. Most importantly, the polar part in the plasticizer can form a strong secondary bond force with the polar part in the polyvinyl chloride resin, thereby significantly optimizing the migration resistance of the outer sheath of the cable.

[0016] Preferably, the flame retardant comprises antimony trioxide, zinc borate and aluminum hydroxide in a weight ratio of (3-15):(6-18):(20-40).

[0017] Preferably, the lubricant is stearic acid.

[0018] Preferably, the conductors and the insulating layers are provided in four groups in total, and a flame-retardant filling rope is provided between each group of conductors and the insulating layer.

[0019] By adopting the above technical solution, the present application arranges four groups of conductors and four corresponding groups of insulation layers, and arranges a flame-retardant filling rope between each group of conductors and the insulation layer, which can significantly improve the overall flame retardancy of the control cable.

[0020] In the second aspect, the present application provides a method for preparing an oil-resistant, high-temperature, and weather-resistant control cable for an oil-immersed transformer, comprising the following steps: blending, kneading, and granulating the raw materials used for the outer sheath to obtain the raw materials used for the outer sheath, then assembling the other parts except the outer sheath in sequence to obtain the cable to be protected, and finally coating the raw materials for the outer sheath on the periphery of the cable to be protected to obtain the oil-resistant, high-temperature, and weather-resistant control cable for the oil-immersed transformer.

[0021] By adopting the above-mentioned technical scheme, the present application prepares an oil-resistant, high-temperature, and weather-resistant control cable for oil-immersed transformers with good low-temperature toughness, high-temperature resistance, high flame retardancy, weather resistance, and oil resistance. The preparation method has simple steps, and the raw materials are readily available, which is suitable for mass production, and provides a strong guarantee for the expanded use of oil-resistant, high-temperature, and weather-resistant control cables for oil-immersed transformers.

[0022] In summary, this application has the following beneficial technical effects: 1. The oil-resistant, high-temperature and weather-resistant control cable for oil-immersed transformers of the present application has excellent oil resistance, heat resistance, flame retardancy, weather resistance and low-temperature resistance. At a temperature of minus 40°C, the low-temperature tensile elongation of the outer sheath is still not less than 40%, which greatly improves the comprehensive performance of the oil-resistant, high-temperature and weather-resistant control cable for oil-immersed transformers, significantly improves the service life of the oil-immersed transformers and the oil-immersed transformers, and effectively expands the scope of application; 2. All non-metallic raw materials used in this application are not hazardous substances restricted for use in electronic and electrical equipment, and have certain environmental significance; 3. The preparation method of the present application has simple steps, readily available raw materials, and is suitable for mass production, providing a strong guarantee for the expanded use of oil-resistant, high-temperature-resistant and weather-resistant control cables for oil-immersed transformers. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a cross-sectional view of an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer in this application.

[0024] Explanation of the reference numerals: 1. conductor; 2. insulation layer; 3. flame retardant filling rope; 4. wrapping layer; 5. shielding layer; 6. isolation sleeve; 7. armor layer; 8. outer sheath. DETAILED DESCRIPTION

[0025] Material Source Unless otherwise specified, the raw materials used in this application are all commercially available products, specifically: Polycarbonate was purchased from Bayer, brand 2407, used after vacuum drying at 120°C for 2 h, Φ3mm×2.5mm; Dioxane was purchased from Tianjin Fuyu Fine Chemical Co., Ltd.; Dimethyldichlorosilane was purchased from Aladdin; Copper wire blanks were purchased from Nanjing Huaxin Nonferrous Metals Co., Ltd., Φ8.0; The insulating layer was purchased from Changshu Zhonglian Optoelectronic New Materials Co., Ltd. The flame retardant filling rope was purchased from Yixing Xinkun Cable Technology Co., Ltd.; The polyester tape was purchased from Liyang Huasu New Materials Co., Ltd. The flame retardant tape was purchased from Weihai Hanyu Chemical Textile Co., Ltd. The isolation sleeve was purchased from Changshu Zhonglian Optoelectronics New Materials Co., Ltd. The armor layer was purchased from Wuxi Zhongsheng Electrical Materials Co., Ltd. Polyvinyl chloride resin was purchased from Xinjiang Tianye Group Co., Ltd.; The stabilizer was purchased from Changzhou Youjia New Material Technology Co., Ltd., brand K7004-5S; Polyethylene wax was purchased from Qingdao Sino New Materials Co., Ltd., brand 119; Stearic acid was purchased from Shanghai Soap Factory, brand 200; Plasticizer DOTP and plasticizer TOTM were purchased from Shandong Lanfan Chemical Co., Ltd.; Antimony trioxide was purchased from Hunan Yiyang Shengli Materials Technology Co., Ltd.; Zinc borate was purchased from Yantai Green Polymer Materials Co., Ltd.; Aluminum hydroxide was purchased from Henan Zhuosheng Flame Retardant Material Co., Ltd., brand ZS-104; Carboxylated nitrile rubber was purchased from Hubei Xinyuhong Biopharmaceutical Technology Co., Ltd., item number xyh001; Carbon black was purchased from Wuxi Kangshenglai Materials Co., Ltd.

[0026] The present application is further described in detail below in combination with preparation examples, embodiments and comparative examples.

[0027] Preparation Example 1 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 30 kg of a 67 wt% dioxane aqueous solution was dropwise added to 80 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular weight polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 15 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0028] Preparation Example 2 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 35 kg of a 67 wt% dioxane aqueous solution was added dropwise to 120 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 18 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0029] Preparation Example 3 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 32 kg of a 67 wt% dioxane aqueous solution was added dropwise to 90 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 16 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0030] Preparation Example 4 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 34 kg of a 67 wt% dioxane aqueous solution was added dropwise to 100 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular weight polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 15 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0031] Preparation Example 5 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 33 kg of a 67 wt% dioxane aqueous solution was added dropwise to 95 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 17 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0032] Preparation Example 6 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 25 kg of a 67 wt% dioxane aqueous solution was added dropwise to 60 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular weight polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 12 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0033] Preparation Example 7 The preparation method of polycarbonate-polydimethylsiloxane block copolymer comprises the following steps: 5.1 kg of polycarbonate was dispersed in 35 L of dioxane, stirred at a constant temperature of 90° C., and after the polycarbonate was completely dissolved, 0.32 kg of ethylene glycol and 0.051 kg of zinc acetate were added. After reacting for 2 hours, the reaction solution was washed with deionized water to remove dioxane and zinc acetate, filtered under reduced pressure, and dried in vacuum to obtain a white solid; 40 kg of a 67 wt% dioxane aqueous solution was dropwise added to 150 kg of dimethyldichlorosilane, heated to 80° C. and refluxed until the liquid phase was clear, and the organic solvent and small molecular polysiloxane were removed by distillation under reduced pressure, and the product was filtered to obtain a clear oily substance; all the white solid, all the clear oily substance and 0.55 kg of triethylamine were dispersed in 25 L of dichloromethane, heated to 80° C. and refluxed for 2 hours, and then the obtained product was washed with water until neutral, poured into methanol for precipitation, filtered, and vacuum dried at 80° C. to obtain a polycarbonate-polydimethylsiloxane block copolymer.

[0034] Examples 1.1-1.5 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer comprises the following steps: S1. Preparation of the cable to be protected: The steel billet wire is processed into Φ3.0mm copper wire by a large drawing machine, and then processed into Φ0.246 thin copper wire by a fine drawing machine. Then the Φ0.246 thin copper wire is divided into 29 coils, and finally twisted into a cross-sectional area of ​​1.5mm by a bundle twisting machine. 2 A conductor is coated with an insulating layer outside the conductor, the nominal thickness of the insulating layer is 0.7 mm, a polyester tape is first coated outside the insulating layer, and then a flame retardant tape is coated to obtain a wrapping layer, the steel billet wire is processed into Φ3.0 mm copper wire through a large drawing machine, and then processed into Φ0.15 thin copper wire through a fine drawing machine, and Φ0.15 thin copper wire is coated outside the wrapping layer to form a shielding layer with a nominal diameter of 0.15 mm, an isolation sleeve is coated outside the shielding layer, the nominal thickness of the isolation sleeve is 1.0 mm, and an armor layer is coated outside the isolation sleeve, the thickness of the armor layer is 0.2 mm, and the cable to be protected is obtained; S2. Preparation of outer sheath and cable assembly: Weigh the raw materials for the outer sheath in the formula amount in Table 1.1, add them into a high-speed mixer, and mix them at a speed of 600r / min and a temperature of 100°C. When the temperature in the system exceeds 110°C, the high-speed mixer automatically opens the discharge valve to discharge the mixed materials into the cold mixing kettle to obtain a first mixed material. The first mixed material is forced into the twin-screw extruder of the two-stage granulating unit for mixing. After mixing, particles are formed by single-screw extrusion of the two-stage granulating unit, wherein the speed of the twin-screw extruder is 290r / min, the temperature of the twin-screw extruder body is controlled at 170°C, the temperatures of the two zones of the single-screw extruder body are 115°C and 125°C respectively, and the feeding speed of the single-screw extruder is 40r / min. Finally, the outer sheath material is produced by extrusion to prepare a sheath layer on the periphery of the cable to be protected, and an oil-resistant, high-temperature and weather-resistant control cable for oil-immersed transformers with a nominal outer sheath thickness of 1.5mm is obtained.

[0035] Table 1.1 Raw material formula used for outer sheath of embodiment 1.1-1.5 (kg) Example 2.1 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 14.25 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 1 is also added, and the rest is the same as Example 1.1.

[0036] Example 2.2 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 19 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 2 is also added, and the rest is the same as Example 1.1.

[0037] Example 2.3 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 14.25 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 3 is also added, and the rest is the same as Example 1.1.

[0038] Example 2.4 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 14.25 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 4 is also added, and the rest is the same as Example 1.1.

[0039] Example 2.5 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer is different from Example 1.1 in that 14.25 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 5 is also added, and the rest is the same as Example 1.1.

[0040] Example 2.6 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 14.25 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 6 is also added, and the rest is the same as Example 1.1.

[0041] Example 2.7 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 14.25 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 7 is also added, and the rest is the same as Example 1.1.

[0042] Example 2.8 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 13 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 1 is also added, and the rest is the same as Example 1.1.

[0043] Example 2.9 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that 20 kg of the polycarbonate-polydimethylsiloxane block copolymer prepared in Preparation Example 1 is also added, and the rest is the same as Example 1.1.

[0044] Example 3 A method for preparing an oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer, which is different from Example 1.1 in that a total of four groups of conductors and the insulating layer are arranged in a central symmetrical manner, and a flame-retardant filling rope is arranged between each group of conductors and the insulating layer, that is, at the symmetrical center. The specific installation method is as follows Figure 1 As shown, the rest is the same as Example 1.1.

[0045] Comparative Example 1 The difference from Example 1.1 is that the powdered nitrile rubber is removed, and the rest is the same as Example 1.1.

[0046] Comparative Examples 2-3 The difference from Example 1.1 is that the dosage of each component is different, see Table 1.3 for details, and the rest is the same as Example 1.1.

[0047] Table 1.3 Raw material formula used for the outer sheath of comparative example 2-3 (kg) Performance Testing 1. Oil resistance: Referring to GB / T 2951.21-2008, the measurement temperature was 100°C, the measurement time was 24h, and the change rates of tensile strength and elongation at break of the cables obtained in the examples and comparative examples were recorded in Table 2; 2. Heat resistance: refer to GB / T 9330-2020, the measurement temperature is 135°C, the measurement time is 168h, and the change rate of tensile strength and elongation at break are shown in Table 2; 3. Flame retardancy: Conduct a Class A combustion test according to GB / T 19666-2019, and record the carbonization height in Table 2; 4. Low temperature resistance: refer to GB / T 9330-2020 and GB / T 2951.14-2008, measure at -40°C, and record the low temperature tensile elongation in Table 2; 5. Weather resistance: refer to GB / T 2423.3-2016, test temperature 85±2℃, humidity 85±5%RH, test time 1000h, and record the cable cracking in Table 2; 6. Environmental protection: All the non-metallic raw materials used above comply with Directive 2001 / 65 / EU on the restriction of the use of certain hazardous substances in electrical and electronic equipment.

[0048] Table 2 Test result record Data Analysis: As can be seen from Table 2, in the oil resistance test of Examples 1.1-1.5, the change rate of tensile strength is 15-19%, the change rate of elongation at break is 15-17%, in the heat resistance test, the change rate of tensile strength is 5-9%, the change rate of elongation at break is 17-25%, the carbonization height is 1.1-1.7m, the low-temperature tensile elongation is 40-45%, and no cracking occurs after weathering treatment at a temperature of 85±2°C and a humidity of 85±5%RH, which proves that the outer sheath prepared by the experimental scheme of the present application and the oil-resistant, high-temperature and weather-resistant control cable for oil-immersed transformers have excellent oil resistance, heat resistance, weather resistance, flame retardancy and low-temperature resistance, and can significantly improve the service life and application scope of oil-immersed transformers; In Examples 2.1-2.9, polycarbonate-polydimethylsiloxane block copolymer is additionally added. At this time, the low-temperature tensile elongation of the outer sheath is significantly improved. The low-temperature tensile elongation of Examples 2.3-2.5 is the highest, and the low-temperature tensile elongation of Examples 2.8-2.9 is lower than that of Examples 2.1-2.7. This proves that the present application adds a certain amount of polycarbonate-polydimethylsiloxane block copolymer, takes advantage of the high polarity of the polycarbonate segment in the main chain, and has good compatibility with the polyvinyl chloride resin, while the poly The dimethylsiloxane segment has the characteristics of good low-temperature flexibility, which significantly improves the low-temperature toughness of the outer sheath, and its oil resistance, heat resistance, flame retardancy and weather resistance are still maintained at a high level. It is also proved that the application strictly controls the addition amount of the polycarbonate-polydimethylsiloxane block copolymer and the amount ratio of the polycarbonate and dimethyldichlorosilane used in the preparation process, so as to balance the toughening effect on the overall system and the uniform compatibility between the components, thereby further improving the low-temperature toughness and other comprehensive properties of the outer sheath; The carbonization height of Example 3 is significantly lower than that of Example 1.1, which proves that the present application can significantly improve the overall flame retardancy of the control cable by providing four groups of conductors and four groups of insulation layers corresponding thereto, and providing a flame retardant filling rope between each group of conductors and the insulation layer; The various properties of comparative examples 1-3 are inferior to those of embodiment 1.1, which proves that there is a good synergistic relationship between the various components of the raw materials used for the outer sheath of the present application, and the material ratio of the present application can significantly optimize the various properties of the cable, so that the oil-resistant, high-temperature-resistant and weather-resistant control cable for oil-immersed transformers has excellent oil resistance, heat resistance, weather resistance, flame retardancy and low-temperature resistance, which can significantly improve the service life and scope of application of the oil-immersed transformer.

[0049] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An oil-resistant, high-temperature and weather-resistant control cable for an oil-immersed transformer, comprising the following structure: a conductor, an insulating layer, a wrapping layer, a shielding layer, a spacer, an armor layer and an outer sheath arranged in sequence from the inside to the outside, characterized in that: The raw materials used for the outer sheath include the following components in parts by weight: 100 parts of polyvinyl chloride resin; 4-6 parts of stabilizer; Polyethylene wax 0.4-0.6 parts; 48-52 parts of plasticizer; Flame retardant 49-53 parts; Powdered nitrile rubber 12-15 parts; Lubricant 0.4-0.6 parts; Colorant 0.5-1 part.

2. The oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer according to claim 1, characterized in that: The raw materials used for the outer sheath include the following components in parts by weight: 100 parts of polyvinyl chloride resin; 5 parts of stabilizer; 0.5 parts of polyethylene wax; Plasticizer 50 parts; Flame retardant 51 parts; Powdered nitrile rubber 14 parts; 0.5 parts of lubricant; 0.5 parts of colorant.

3. The oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer according to claim 1, characterized in that: The raw materials used for the outer sheath also include polycarbonate-polydimethylsiloxane block copolymer, and the amount of the polycarbonate-polydimethylsiloxane block copolymer is 15-20wt% of the amount of the polyvinyl chloride resin.

4. The oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer according to claim 3, characterized in that: In the preparation process of the polycarbonate-polydimethylsiloxane block copolymer, the amount ratio of polycarbonate to dimethyldichlorosilane is 5.1:(90-100).

5. The oil-resistant, high-temperature-resistant and weather-resistant control cable for oil-immersed transformer according to claim 1, characterized in that: The plasticizer includes plasticizer DOTP and plasticizer TOTM in a weight ratio of 20:

30.

6. The oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer according to claim 1, characterized in that: The flame retardant comprises antimony trioxide, zinc borate and aluminum hydroxide in a weight ratio of (3-15):(6-18):(20-40).

7. The oil-resistant, high-temperature-resistant and weather-resistant control cable for an oil-immersed transformer according to claim 1, characterized in that: The lubricant is stearic acid.

8. The oil-resistant, high-temperature-resistant and weather-resistant control cable for oil-immersed transformer according to claim 1, characterized in that: The conductors and the insulating layers are arranged in four groups in total, and a flame retardant filling rope is arranged between each group of conductors and the insulating layer.

9. A method for preparing the oil-resistant, high temperature-resistant and weather-resistant control cable for oil-immersed transformers according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials for the outer sheath are blended, kneaded, and granulated to obtain the raw materials for the outer sheath, and then the other parts except the outer sheath are assembled in sequence to obtain the cable to be protected. Finally, the raw materials for the outer sheath are coated on the periphery of the cable to be protected to obtain the oil-resistant, high-temperature-resistant and weather-resistant control cable for oil-immersed transformers.

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