CN204884602U - Crosslinked polyethylene insulating material's cable for overhead insulated cable that contains graphite alkene - Google Patents

Abstract

The utility model discloses a cable of cross-linked polyethylene insulating material used for an overhead insulating cable containing graphene, and the technical problem to be solved is to reduce the cost of the overhead insulating cable. The utility model adopts the following technical solutions: a cable of cross-linked polyethylene insulating material used for overhead insulated cables containing graphene, the conductor is covered with an insulating layer, and the thickness of the insulating layer is reduced by 5-10%. Compared with the prior art, the utility model adds graphene and graphene oxide to the cross-linked polyethylene insulating material, cooperates with the auxiliary heat conducting agent, and improves the thermal conductivity, ultraviolet resistance and weather resistance of the insulation layer of the overhead insulated cable. The performance of the insulation layer is more excellent. Compared with the insulation layer of the prior art, the thickness of the insulation layer of the overhead insulated cable can be reduced by 5-10%, which greatly reduces the cost of the overhead insulated cable and reduces the difficulty of erecting the cable.

Description

Cables with cross-linked polyethylene insulation materials for overhead insulated cables containing graphene

technical field

The utility model relates to a cable, in particular to an overhead insulated cable.

Background technique

Aerial insulated cables (cables) are mainly used for overhead laying in urban and rural distribution networks. The cables are exposed outdoors for a long time and are easily affected by various harsh environments, such as ultraviolet rays, high temperatures, low temperatures, etc., and the insulation layer is easy to age. Adding no less than 2.6% of carbon black to the ethylene insulating material still does not meet the requirements of the insulating material for UV resistance and weather-induced aging, resulting in a reduction in the service life of the cable. The cable has only one layer of insulation, and the heat dissipation is relatively better than other cables, so the carrying capacity is larger, and the current passing through the conductor is also larger. Due to the change of temperature in the air, when the air temperature becomes higher, the heat dissipation capacity of the cable decreases, and the conductor temperature will increase under the same current density, and the conductor temperature will increase, and the DC resistance of the conductor will increase, while the DC resistance will increase. The heat generated will be more, and the loss caused by the temperature rise of the conductor during the power transmission process accounts for about 15% of the transmitted power. Reducing the temperature of the conductor can reduce the loss of electric energy, so it is of great significance to reduce the temperature of the cable conductor. The important factor affecting the temperature of the cable conductor is the insulating layer outside the conductor, and the cross-linked polyethylene insulating layer material is a high heat-resistant material with a very low thermal conductivity of 0.2W/mk. The cross-linked polyethylene insulated overhead cable is in the air Working, the air temperature is 20°C, and in a windless environment, when the conductor temperature reaches 90°C, the cable surface temperature is only 60°C, and the temperature gradient from the conductor to the cable surface can reach 30°C, the heat dissipation is very poor, resulting in increased transmission power loss . Adding carbon black to the insulating material makes the insulating layer thicker, not only the weight of the cable is larger, the cost is higher, but also the difficulty of erecting the cable is increased.

Contents of the invention

The purpose of the utility model is to provide a graphene-containing cable of cross-linked polyethylene insulating material for overhead insulated cables, and the technical problem to be solved is to reduce the cost of overhead insulated cables.

The utility model adopts the following technical solutions: a cable of cross-linked polyethylene insulating material used for overhead insulated cables containing graphene, the conductor is covered with an insulating layer, and the thickness of the insulating layer is reduced by 5-10%.

The conductor of the utility model is covered with a semi-conductive shielding layer.

The heat conducting agent of the utility model is graphene or graphene oxide.

The semi-conductive shielding layer of the utility model adopts the semi-conductive material with ethylene-vinyl acetate copolymer as the base material and added with carbon black, and its resistivity is not greater than 1000Ω.m.

Compared with the prior art, the utility model adds graphene and graphene oxide to the cross-linked polyethylene insulating material, cooperates with the auxiliary heat conducting agent, and improves the thermal conductivity, ultraviolet resistance and weather resistance of the insulation layer of overhead insulated cables, The performance of the insulation layer is more excellent. Compared with the insulation layer of the prior art, the thickness of the insulation layer of the overhead insulated cable can be reduced by 5-10%, which greatly reduces the cost of the overhead insulated cable and reduces the difficulty of erecting the cable.

Description of drawings

Fig. 1 is a schematic structural view of Embodiment 7 of the present utility model.

Fig. 2 is a schematic structural view of Embodiment 13 of the present utility model.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail. The cable of cross-linked polyethylene insulating material (insulating material) used for overhead insulated cables containing graphene of the utility model is composed of the following materials in parts by mass: 80-90 parts of low-density polyethylene LDPE, 10-90 parts of linear low-density polyethylene LLDPE 20 parts, heat conducting agent 0.05-3.5 parts, auxiliary heat-conducting agent 1-5 parts, silane coupling agent 0.5-3 parts, antioxidant 0.11-0.21 parts, plasticizer 0.03-0.15 parts, initiator 0.03-0.15 parts.

Low-density polyethylene (LDPE) is the main component of insulating materials for overhead insulated cables (cables). It has good insulation properties and suitable physical and mechanical properties. There are many short branches on the LDPE molecular chain, which is conducive to grafting and crosslinking.

Linear low-density polyethylene LLDPE has good insulation performance, and there are few short chain branches on the molecular chain. Adding it can improve the extrusion process performance of the material.

The heat conducting agent is graphene or graphene oxide. Graphene is a two-dimensional carbon material with excellent electrical and thermal conductivity, excellent ultraviolet absorption performance and weather aging resistance. The thermal conductivity can reach 5000W/mk. Graphene oxide is a product exfoliated by chemical graphite oxide powder, its performance is similar to that of graphene, and its thermal conductivity can reach 3000W/mk. Due to the excellent conductivity of graphene or graphene oxide, it cannot be added in the cable insulation material. If it exceeds a certain ratio, the insulation performance of the cable insulation material will be greatly reduced.

The auxiliary heat conducting agent is more than one of aluminum nitride ALN, boron nitride BN, silicon carbide SiC and carbon fiber. Among them, aluminum nitride ALN is 1-5 parts, and boron nitride BN is 1-5 parts. Auxiliary thermal conductive agents can be coupled to improve the thermal conductivity of insulating materials. Since the heat conduction agent has good electrical conductivity, it cannot be added too much in the cable insulation material, and if it is added too little, it cannot improve the thermal conductivity. Therefore, an auxiliary heat conduction agent is added to improve the thermal conductivity. The auxiliary heat-conducting agent has good electrical insulation performance, and the thermal conductivity is between 20 and 80W/mk. It can be used in conjunction with the heat-conducting agent to significantly improve the thermal conductivity of the cable insulation material.

The silane coupling agent uses vinyltrimethoxysilane as a crosslinking agent. After polyethylene is crosslinked, thermoplastic polyethylene PE becomes thermosetting crosslinked polyethylene XLPE, which can increase the temperature resistance level of cable insulation materials from 70°C to 90 ℃, the carrying capacity of the cable is greatly increased.

The antioxidants are antioxidant 1010 and antioxidant 300#. Among them, antioxidant 1010 is 0.1-0.2 parts, and antioxidant 300# is 0.01 parts. Antioxidants are used to prevent oxidative degradation of cable insulation materials and improve service life.

The plasticizer is dibutyltin dilaurate. Plasticizers can enhance the flexibility of insulation materials and facilitate processing.

The initiator is dicumyl peroxide DCP. Initiators are used to initiate the silane crosslinking reaction.

The cross-linked polyethylene insulating material used for overhead insulated cables containing graphene of the utility model is made according to the method of the prior art, and comprises the following steps:

1. Measure and mix 80-90 parts of low-density polyethylene LDPE pellets and 10-20 parts of linear low-density polyethylene LLDPE pellets in parts by mass.

2. Measure and mix 0.05 to 3.5 parts of heat conducting agent and 1 to 5 parts of auxiliary heat conducting agent in parts by mass.

3. Measure and mix 0.5-3 parts of silane coupling agent, 0.11-0.21 parts of antioxidant, 0.03-0.15 parts of plasticizer and 0.03-0.15 parts of initiator in parts by mass.

4. The mixed materials obtained in steps 1, 2 and 3 are respectively kneaded, plasticized and pelletized by a granulator to obtain particles, and the particles are cooled to room temperature (25° C.) by an air-cooled cooling system.

5. The shape of the particles after cooling is round or oblate with a diameter of 2 to 3 mm. After mixing, they are vacuum-packed to obtain mixture particles of cross-linked polyethylene insulating materials for overhead insulated cables containing graphene.

When making cables, the mixture particles are extruded and coated on the conductor or shield of the overhead insulated cable according to the prior art method, and cross-linked in water or steam at a temperature not lower than 90°C for 4 to 8 hours.

The insulating materials obtained in the examples are used to make overhead insulated cables, which must meet the following national standards.

Conductor DC resistance is tested in accordance with GB/T3048.4-2007 "Test Methods for Electrical Properties of Wires and Cables", Part 4: Conductor DC Resistance Test, and the test results must comply with GB/T12527-2008 "Overhead Insulated Cables with Rated Voltage 1kV and Below" and GB/T14049-2008 "Rated voltage 10kV overhead insulated cables" requirements.

The AC voltage test is in accordance with GB/T3048.8-2007 "Electrical Performance Test Methods of Wires and Cables" Part 8: AC voltage test, the rated voltage is 0.6/1kV, the test voltage is 3500V for 5 minutes without breakdown; the rated voltage is 10kV common type 18kV test voltage for cables without breakdown for 5 minutes; cables with light and thin insulation structure without breakdown for 12kV test voltage for 5 minutes.

Insulation tensile strength is tested in accordance with GB/T2951.11-2008 "General Test Methods for Cable Insulation and Sheath Materials", Part 11: General Test Methods Section 1 Mechanical Performance Test, and the result is not less than 12.5N/mm ² .

After aging, the elongation at break of the insulation is tested according to GB/T2951.12-1997 "General Test Methods for Cable Insulation and Sheath Materials", Part 12: General Test Methods - Thermal Aging Test, and the result is not less than 200%.

The insulation tensile strength test after aging is in accordance with GB/T2951.12-2008 "General Test Methods for Cable Insulation and Sheathing Materials", Part 12: General Test Method - Thermal Aging Test, and the rate of change in tensile strength after aging is not greater than ±25 %.

Insulation elongation at break after aging is in accordance with GB/T29511.12-2008 "General Test Methods for Cable Insulation and Sheathing Materials", Part 12: General Test Method - Thermal Aging Test, and the change rate of elongation at break after aging is not greater than ± 25%.

The thermal extension test is in accordance with GB/T2951.21-2008 "General Test Methods for Cable Insulation and Sheathing Materials", Part 21: Special Experimental Method for Elastomer Compounds - Ozone Resistance Test - Thermal Extension Test - Mineral Oil Immersion Test, the test results meet GB/T12527-2008 and GB/T14049-2008 requirements.

Insulation UV resistance and weather resistance tests are tested in accordance with Appendix A of GB/T12527-2008 "Overhead Insulated Cables with Rated Voltage 1kV and Below" and Appendix C of GB/T14049-2008 "Overhead Insulated Cables with Rated Voltage 10kV", and the test results meet their requirements.

The thermal conductivity test of the cable insulation material is in accordance with the test method of GB/T10297-1998 "Hot Wire Method for Determination of Thermal Conductivity of Non-metallic Solid Materials", and the thermal conductivity of the material is not less than 0.30W/mk.

Embodiment 1, cross-linked polyethylene insulating material for overhead insulated cables containing graphene, consists of the following materials in parts by mass: 80 parts of low-density polyethylene, 20 parts of linear low-density polyethylene, 0.05 parts of heat-conducting agent graphene, auxiliary 5 parts of heat conducting agent aluminum nitride, 0.5 part of silane coupling agent vinyltrimethoxysilane, 10100.2 parts of antioxidant, 0.01 part of antioxidant 300#, 0.03 part of plasticizer dibutyltin dilaurate, initiator DCP0. 03 copies.

Embodiment 2, cross-linked polyethylene insulating material for overhead insulated cables containing graphene, consists of the following materials in parts by mass: 90 parts of low-density polyethylene, 10 parts of linear low-density polyethylene, 3.5 parts of heat-conducting agent graphene oxide, 1 part of auxiliary thermal conductive agent aluminum nitride, 3 parts of silane coupling agent vinyltrimethoxysilane, 10100.1 parts of antioxidant, 0.01 part of antioxidant 300#, 0.15 part of plasticizer dibutyltin dilaurate, initiator DCP0 .15 servings.

Embodiment 3, cross-linked polyethylene insulating material for overhead insulated cables containing graphene, consists of the following materials in parts by mass: 85 parts of low-density polyethylene, 15 parts of linear low-density polyethylene, 0.5 parts of heat-conducting agent graphene, auxiliary 3 parts of heat conducting agent aluminum nitride, 1 part of silane coupling agent vinyltrimethoxysilane, 10100.1 parts of antioxidant, 0.01 part of antioxidant 300#, 0.1 part of plasticizer dibutyltin dilaurate, initiator DCP0. 1 serving.

Embodiment 4, cross-linked polyethylene insulating material for overhead insulated cables containing graphene, consists of the following materials in parts by mass: 85 parts of low-density polyethylene, 15 parts of linear low-density polyethylene, 1 part of heat-conducting agent graphene, auxiliary 3 parts of heat conducting agent aluminum nitride, 1.4 parts of silane coupling agent vinyltrimethoxysilane, 10100.12 parts of antioxidant, 0.01 part of antioxidant 300#, 0.08 part of plasticizer dibutyltin dilaurate, initiator DCP0. 08 copies.

Embodiment 5, cross-linked polyethylene insulating material for overhead insulated cables containing graphene, consists of the following materials in parts by mass: 85 parts of low-density polyethylene, 15 parts of linear low-density polyethylene, 0.7 parts of heat-conducting agent graphene, auxiliary Heat conduction agent aluminum nitride 5 parts, silane coupling agent vinyltrimethoxysilane 1.4 parts, antioxidant 10100.12 parts, antioxidant 300# 0.01 part, plasticizer dibutyltin dilaurate 0.08 part, initiator DCP0. 08 copies.

Embodiment 6, cross-linked polyethylene insulating material for overhead insulated cables containing graphene, consisting of the following materials in parts by mass: 85 parts of low-density polyethylene, 15 parts of linear low-density polyethylene, and 1.2 parts of heat-conducting agent graphene oxide , 4 parts of auxiliary thermal conductive agent aluminum nitride, 1.4 parts of silane coupling agent vinyltrimethoxysilane, 10100.12 parts of antioxidant, 0.01 part of antioxidant 300#, 0.08 part of plasticizer dibutyltin dilaurate, initiator DCP0.08 copies.

In Examples 7 to 12, the insulating materials obtained in Examples 1 to 6 were respectively used to manufacture overhead insulated cables with a voltage level of 0.6/1 kV. As shown in FIG. 1 , an overhead insulated cable includes a conductor 1 and an insulating layer 2 outside the conductor 1 . The cross-section of conductor 1 is a circular compact structure formed by twisting multiple strands of wires, using copper, aluminum or aluminum alloy wires and stranded wires with steel cores, extruded and coated (extruded) on the outside of conductor 1 with an insulating layer 2. The insulating layer 2 is formed by extruding the insulating materials in Examples 1-6 respectively.

In Examples 13 to 18, the insulating materials obtained in Examples 1 to 6 were respectively used to manufacture overhead insulated cables with a voltage level of 10 kV. As shown in Figure 2, the overhead insulated cable includes a conductor 1, a semiconductive shielding layer 3 coated on the outside of the conductor 1, and an insulating layer 2 is extruded and coated on the outside of the semiconductive shielding layer 3, and the insulating layer 2 adopts the method of embodiment 1 respectively. ~6 insulation materials are extruded. The semi-conductive shielding layer 3 is made of ethylene-vinyl acetate copolymer EVA as the base material, and the semi-conductive material with carbon black is added. Its resistivity is not greater than 1000Ω. too high a field strength.

Test and analyze according to the test method of GB/T10297-1998 "Hot Wire Method for Determination of Thermal Conductivity of Non-metallic Solid Materials":

The thermal conductivity of the insulating layer extruded with the insulating material of Example 1 is 0.22W/mk. Due to the small amount of thermal conductive agent added, the thermal conductivity effect is not obvious.

The thermal conductivity of the insulating layer extruded with the insulating material of Example 2 is 0.41W/mk, and the thermal conductivity is good. Due to the large number of added graphene oxide, the cost is relatively high.

The thermal conductivity of the insulating layer extruded with the insulating material of Example 3 is 0.24W/mk. Compared with the insulating material of Example 1, the amount of the thermal conductive agent graphene is increased, and the thermal conductivity effect is increased.

The thermal conductivity of the insulating layer extruded with the insulating material of Example 4 is 0.34W/mk, and the thermal conductivity is better. Due to the addition of a large number of thermal conductive agent graphene, the cost is relatively high.

The thermal conductivity of the insulating layer extruded with the insulating material of Example 5 is 0.31 W/mk, the thermal conductivity is better, and the cost is relatively low, which is ideal.

The insulating layer extruded with the insulating material of Example 6 is made of graphene oxide, the thermal conductivity is 0.32W/mk, the thermal conductivity is good, and the cost is relatively low, which is ideal.

Other inspection items of embodiments 7～12, 13～18:

Conductor DC resistance is tested in accordance with GB/T3048.4-2007 "Test Methods for Electrical Properties of Wires and Cables", Part 4: Conductor DC Resistance Test, and the test results are in line with GB/T12527-2008 "Overhead Insulated Cables with Rated Voltage 1kV and Below" and GB /T14049-2008 "Rated Voltage 10kV Overhead Insulated Cable" requirements.

The AC voltage test is in accordance with GB/T3048.8-2007 "Electrical Performance Test Methods of Wires and Cables" Part 8: AC voltage test, the rated voltage is 0.6/1kV cable 3500V test voltage 5min without breakdown; the rated voltage is 10kV ordinary cable 18kV No breakdown of the test voltage for 5 minutes; no breakdown of the light thin insulation structure cable for 12kV test voltage of 5 minutes.

Insulation tensile strength is tested in accordance with GB/T2951.11-2008 "General Test Methods for Cable Insulation and Sheath Materials", Part 11: General Test Methods Section 1 Mechanical Performance Test, and the result is not less than 12.5N/mm ² .

After aging, the elongation at break of the insulation is tested according to GB/T2951.12-1997 "General Test Methods for Cable Insulation and Sheath Materials", Part 12: General Test Methods - Thermal Aging Test, and the result is not less than 200%.

The insulation tensile strength test after aging is in accordance with GB/T2951.12-2008 "General Test Methods for Cable Insulation and Sheathing Materials", Part 12: General Test Method - Thermal Aging Test, and the change rate of tensile strength after aging is not greater than ±25 %.

Insulation elongation at break after aging is in accordance with GB/T29511.12-2008 "General Test Methods for Cable Insulation and Sheathing Materials", Part 12: General Test Method - Thermal Aging Test, and the change rate of elongation at break after aging is not greater than ± 25%.

The thermal extension test is in accordance with GB/T2951.21-2008 "General Test Methods for Cable Insulation and Sheathing Materials", Part 21: Special Experimental Method for Elastomer Compounds - Ozone Resistance Test - Thermal Extension Test - Mineral Oil Immersion Test, the test results meet GB/T12527-2008 and GB/T14049-2008 requirements.

Insulation UV resistance and weather resistance tests are tested in accordance with Appendix A of GB/T12527-2008 "Overhead Insulated Cables with Rated Voltage 1kV and Below" and Appendix C of GB/T14049-2008 "Overhead Insulated Cables with Rated Voltage 10kV", and the test results meet their requirements.

After testing, the thermal conductivity of the cable insulation layer in Example 5 reaches 0.31W/mk. The thermal conductivity of the cable insulation layer in Example 6 reaches 0.32W/mk, and other inspection items according to the above insulation ultraviolet resistance and weather resistance tests also meet the provisions of the above-mentioned national standards.

Increasing the thermal conductivity of the insulating layer of overhead insulated cables can effectively reduce the conductor temperature. The thermal conductivity of graphene can reach about 5000W/mk, and graphene oxide can reach 3000W/mk. It is a very good thermal conductivity material, and it is firm and hard with a stable structure. At the same time, graphene and graphene oxide have good UV resistance and weather resistance, which can improve the UV resistance and weather resistance of the insulating layer of overhead insulated cables. Also because graphene and graphene oxide are very good conductive materials, in view of the special requirements of the insulating layer material on its insulating properties and on the tensile strength of the cable insulation and the elongation at break of the insulation, the utility model adds suitable A large amount of graphene or graphene oxide, combined with an auxiliary heat-conducting agent, is used to modify the insulating layer material, while maintaining the tensile strength of the cable insulation and the elongation at break of the insulation in line with the national standard, to improve its thermal conductivity. Under the load condition when it reaches 90°C, if the thermal conductivity of the insulating layer is increased from 0.20W/mk to above 0.3W/mk, the cable conductor temperature can be reduced by 2-4°C. If the conductor temperature remains unchanged at 90°C, the cable load The flow rate can be increased by 3-4%.

Because the insulating material of the present invention is added with graphene and graphene oxide, and is combined with an auxiliary heat conducting agent, the thermal conductivity, ultraviolet resistance and weather resistance of the insulating layer of overhead insulated cables are improved, making the performance of the insulating layer more excellent, compared with existing With advanced insulation layer, the thickness of the insulation layer of overhead insulated cables can be reduced by 5-10%, which greatly reduces the cost of overhead insulated cables and reduces the difficulty of erecting cable construction.

Claims (4)

1. a cable for the aerial insulated cable crosslinked polyethylene insulation material of graphene-containing, conductor (1) is coated with insulating barrier (2), it is characterized in that: the reduced thickness 5 ~ 10% of described insulating barrier (2).

2. the cable of the aerial insulated cable crosslinked polyethylene insulation material of graphene-containing according to claim 1, is characterized in that: described conductor (1) is coated with semiconductive shielding layer (3).

3. the cable of the aerial insulated cable crosslinked polyethylene insulation material of graphene-containing according to claim 2, is characterized in that: thermal conducting agent is Graphene or graphene oxide.

4. the cable of the aerial insulated cable crosslinked polyethylene insulation material of graphene-containing according to claim 3, it is characterized in that: it is base material that described semiconductive shielding layer (3) adopts with ethylene-vinyl acetate copolymer, add the semiconductive material having carbon black, its resistivity is not more than 1000 Ω .m.