Anti-breakdown and anti-aging power cable

Abstract

The invention relates to a breakdown-resistant and aging-resistant power cable. A power cable has high anti-breakdown and anti-aging requirements, however, cable materials used at present, such as polyethylene, are poor in anti-aging capability. In order to solve the problem, the breakdown-resistant and aging-resistant power cable is invented, the breakdown-resistant and aging-resistant power cable is sequentially composed of a conductor, a conductor shielding layer, an insulating layer, a wrapping layer and a protective layer from inside to outside, and the conductor shielding layer is a composite shielding material composed of organic silicon, graphene and nano molybdenum dioxide. The organic silicon in the conductor shielding layer has good heat resistance and aging resistance; the graphene has good electric conduction and heat conduction performance, can shield electromagnetic waves, and can conduct heat out to reduce the temperature; the nano molybdenum dioxide can react with peroxide at high temperature, so that the degradation effect of the organic silicon resin is delayed, and the aging resistance of the cable can be effectively improved by combining the nano molybdenum dioxide, the peroxide and the organic silicon resin. The breakdown-resistant and aging-resistant power cable can be used in the fields of high-voltage power cables and the like.

Description

Technical Field

[0001] The invention relates to a power cable, in particular to a penetration-resistant and aging-resistant power cable. Background Art

[0002] With the acceleration of urbanization and modernization in my country, the domestic power system is also developing rapidly, and the demand for cross-linked polyethylene medium and high voltage power cables is increasing year by year. IEC 502 stipulates that cables with rated voltages above 1.8 / 3.0kV and with polyvinyl chloride, ethylene propylene rubber insulation and rated voltages above .6 / 6.0kV must use inner and outer semi-conductive shielding layers.

[0003] The basic function of the shielding layer is to confine the electric field in the cable to isolate it from the external electric field and obtain a uniform electric field distribution in the insulation layer. At the same time, the shielding layer also provides a smooth, continuous, conductive, equipotential interface between the insulation layer and the conductor. The cable shielding layer is divided into conductor shielding (inner shielding) and insulation shielding (outer shielding).

[0004] Semi-conductive shielding materials are polymer composite materials that have a certain conductivity after being filled with a certain amount of conductive filler. They are mainly made of matrix resin, conductive filler and other additives. Commonly used matrix resins at home and abroad are ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA) and low-density polyethylene copolymer (LDPE). However, the heat and aging resistance of these polymers are relatively low, and their performance is slightly inferior to that of high-temperature resistant polymers such as silicone rubber.

[0005] Chinese patent CN 201710230310.6 discloses a power cable, including a conductor, a conductor shielding layer wrapped on the outside of the conductor, an insulating rubber layer wrapped on the outside of the conductor shielding layer, a sheathing layer on the outside of the insulating rubber layer, a rubber protective layer on the outside of the sheathing layer, and a nano-composite graphene shielding material. The main feature of this patent is that the synthesis method of adding nano-composite graphene shielding material is applied to power cables. The process is simple to operate and the raw materials are relatively easy to obtain. By adding nano-composite graphene, it has better thermal stability at high temperature, lower hygroscopicity and low viscosity that is conducive to improving production, and improves the breakdown strength of the shielding material.

[0006] However, this patent still uses polyethylene as the base resin of the conductor shielding layer, and the resin has low heat resistance and aging resistance, which limits the application of the cable.

[0007] Therefore, how to prepare high temperature resistant and aging resistant shielding materials to improve the anti-puncture and aging resistance of power cables is a technical problem to be solved in this field. Summary of the invention

[0008] In order to solve the problem that the cable shielding material in the prior art has insufficient anti-puncture and aging performance, the present invention proposes the following technical solution: A penetration-resistant and aging-resistant power cable comprises a conductor, wherein the outer side of the conductor is wrapped with a conductor shielding layer, the outer side of the conductor shielding layer is wrapped with an insulating layer, the outer side of the insulating layer is a wrapping layer, the outer side of the wrapping layer is a protective layer, and the conductor shielding layer is a silicone / graphene / nano-molybdenum dioxide shielding material.

[0009] The preparation process of the conductor shielding layer comprises the following steps: S1: Disperse vinyl siloxane coupling agent (A171) and nano molybdenum dioxide in water at a mass ratio of 2:1, add acetic acid to adjust the pH value to 3-4, ultrasonically vibrate, react at 50°C for two hours, centrifuge to obtain the precipitate, wash and dry to obtain modified nano molybdenum dioxide; S2: 100 parts of vinyl silicone oil, 30-50 parts of graphene, 5 parts of water, 20 parts of vinyl siloxane coupling agent (A171), and 5-10 parts of modified nano molybdenum dioxide described in S1 are mixed, acetic acid is added dropwise to adjust the pH value to 3-4, and the mixture is ground in a planetary ball mill for 24 hours to obtain a mixture A; S3 The mixture A obtained in S2 is stirred and mixed with 35 parts of hydrogenated silicone oil, 0.5 parts of platinum catalyst and 5 parts of water to obtain a mixture B; S4: coating the mixture B obtained in S3 on the metal core wire, and drying at 160° C. for 5 minutes to obtain the conductor shielding layer.

[0010] The present invention has the following effects: Graphene has a unique single atomic layer two-dimensional structure and conjugated carbon network structure. It has special geometric characteristics of large specific surface area and high aspect ratio, as well as high electron mobility, mechanical elasticity, and excellent thermal properties. Using it as a shielding material can improve the shielding material's anti-puncture strength. At the same time, stacked graphene can prevent the evolution of electrical trees into the inner layer of polymer materials.

[0011] Compared with Chinese patent CN 201710230310.6, the present invention uses silicone rubber as the base resin of the inner shielding layer. Silicone rubber has excellent heat resistance, weather resistance, and aging resistance, and can better improve the cable's anti-puncture and aging resistance compared to polyethylene.

[0012] As a highly conductive material, nano molybdenum dioxide can effectively improve the shielding efficiency of the inner shielding layer. At the same time, nano molybdenum dioxide can react with peroxides to delay the degradation of resins and improve the anti-aging properties of cables. Using coupling agent A171 to treat nano molybdenum dioxide can effectively improve the dispersibility of nano molybdenum dioxide in the matrix resin and improve the performance of cable shielding materials. DETAILED DESCRIPTION

[0013] The present application is further described in detail below with reference to the embodiments.

[0014] raw material The raw materials in the examples of this application can be obtained from commercial sources: Vinyl silicone oil, vinyl molar fraction 0.23% ~ 10%, viscosity (25 ℃) 3000 ~ 50000mPa·s; Hydrogen-containing silicone oil, active hydrogen molar fraction 0.3% ~ 0.5%, viscosity (25 ℃) 20 ~ 50 mPa·s; Platinum catalyst, platinum content 0.5%; Graphene, industrial grade; Vinyl siloxane coupling agent (A171), purity 99%; Nano molybdenum dioxide, particle size 50-100nm, purity 99%.

[0015] Example

[0016] Example 1 A penetration-resistant and aging-resistant power cable comprises a conductor, wherein the outer side of the conductor is wrapped with a conductor shielding layer, the outer side of the conductor shielding layer is wrapped with an insulating layer, the outer side of the insulating layer is a wrapping layer, the outer side of the wrapping layer is a protective layer, and the conductor shielding layer is a silicone / graphene / nano-molybdenum dioxide shielding material.

[0017] The preparation process of the conductor shielding layer comprises the following steps: S1: Disperse vinyl siloxane coupling agent (A171) and nano molybdenum dioxide in water at a mass ratio of 2:1, add acetic acid to adjust the pH value to 3-4, ultrasonically vibrate, react at 50°C for two hours, centrifuge to obtain the precipitate, wash and dry to obtain modified nano molybdenum dioxide; S2: 100 parts of vinyl silicone oil, 50 parts of graphene, 5 parts of water, 20 parts of vinyl siloxane coupling agent (A171), and 10 parts of modified nano-molybdenum dioxide described in S1 are mixed, acetic acid is added dropwise to adjust the pH value to 3-4, and the mixture is ground in a planetary ball mill for 24 hours to obtain a mixture A; S3 The mixture A obtained in S2 is stirred and mixed with 35 parts of hydrogenated silicone oil, 0.5 parts of platinum catalyst and 5 parts of water to obtain a mixture B; S4: coating the mixture B obtained in S3 on the metal core wire, and drying at 160° C. for 5 minutes to obtain the conductor shielding layer.

[0018] Example 2-3 The difference from Example 1 is that the raw material ratio of the conductor shielding material is different, see Table 1 for details.

[0019] Table 1 Raw material ratio table of Examples 1-3 Example 1 Example 2 Example 3 Vinyl silicone oil 100 100 100 Hydrogenated silicone oil 35 35 35 Graphene 50 30 50 Modified Nano Molybdenum Dioxide 10 10 5 Platinum catalyst 0.5 0.5 0.5

[0020] Comparative Example 1 The difference from Example 1 is that no nano molybdenum dioxide is added.

[0021] Comparative Example 2 Different from Example 1, the nano-molybdenum dioxide is not treated with a vinyl siloxane coupling agent (A171).

[0022] Comparative Example 3 Different from Example 1, graphene is not added.

[0023] Performance testing

[0024] Detection method / test method According to the Guidelines for Statistical Analysis of Electrical Insulation Breakdown Data GB∕T 29310-2012, after 0d and 150d accelerated aging, power frequency step-by-step breakdown tests were performed on Examples 1-3 and Comparative Examples 1-3.

[0025] The test results are shown in Table 2 Table 2 Power frequency step-by-step breakdown test results Eb / (kv∙mm -1 ) Heat aging 0 days Heat aging 150 days Example 1 76.8 73.4 Example 2 74.2 70.1 Example 3 75.3 68.7 Comparative Example 1 70.6 50.1 Comparative Example 2 73.8 67.5 Comparative Example 3 40.1 25.8

[0026] Combining Examples 1-3 and Comparative Examples 1-3, it can be seen that the anti-puncture performance and aging resistance of Examples 1-3 are better than those of Comparative Examples 1-3, which indicates that the anti-puncture performance and aging resistance of the cable prepared in the present application are better.

[0027] It can be seen from Example 1 and Comparative Example 1 that nano molybdenum dioxide can effectively improve the anti-puncture and anti-aging properties of the cable.

[0028] It can be seen from Example 1 and Comparative Example 2 that the nano-molybdenum dioxide modified by the coupling agent can be effectively dispersed in the resin, effectively improving the anti-puncture and anti-aging properties of the cable.

[0029] It can be seen from Example 1 and Comparative Example 3 that graphene can effectively improve the anti-puncture and anti-aging properties of the cable.

[0030] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A puncture-resistant and aging-resistant power cable, comprising a conductor, a conductor shielding layer wrapped on the outside of the conductor, an insulating layer wrapped on the outside of the conductor shielding layer, a wrapping layer on the outside of the insulating layer, a protective layer on the outside of the wrapping layer, and the conductor shielding layer is a silicone / graphene / nano-molybdenum dioxide shielding material.

2. The preparation process of the conductor shielding layer comprises the following steps: S1: Disperse vinyl siloxane coupling agent (A171) and nano molybdenum dioxide in water at a mass ratio of 2:1, add acetic acid to adjust the pH value to 3-4, ultrasonically vibrate, react at 50°C for two hours, centrifuge to obtain the precipitate, wash and dry to obtain modified nano molybdenum dioxide; S2: 100 parts of vinyl silicone oil, 30-50 parts of graphene, 5 parts of water, 20 parts of vinyl siloxane coupling agent (A171), and 5-10 parts of modified nano molybdenum dioxide described in S1 are mixed, acetic acid is added dropwise to adjust the pH value to 3-4, and the mixture is ground in a planetary ball mill for 24 hours to obtain a mixture A; S3 The mixture A obtained in S2 is stirred and mixed with 35 parts of hydrogenated silicone oil and 0.5 parts of a platinum catalyst to obtain a mixture B; S4: coating the mixture B obtained in S3 on the metal core wire, and drying at 160° C. for 5 minutes to obtain the conductor shielding layer.