CN206685190U - A kind of aluminium alloy fire-proof medium-voltage cable - Google Patents

Abstract

The utility model provides an aluminum alloy fire-resistant medium-voltage cable, which includes a cable core and an outer cladding wrapped outside the cable core. The cable core includes one or more insulating wire cores and ceramic fiber cotton filling layers (6). The core includes an aluminum alloy conductor (1), and the outer cladding includes a ceramic fiber tape wrapping layer (7), a low-smoke, halogen-free oxygen barrier layer (8), and a ceramic silicon rubber tape wrapping layer arranged in sequence from the inside to the outside. (9) and a ceramized polyolefin sheath layer (10). The utility model enables the cable to achieve good thermal insulation and economic efficiency through the optimized setting of the cable core filling layer and the outer cladding layer. Within 90 minutes, the temperature of the outer layer flame transmitted to the cable insulation layer does not exceed 330°C. The insulation layer is less damaged, and it meets the characteristics of non-toxicity, low smoke, and flame retardancy when burning, and the amount of materials used is small, and the price of materials is low, which makes the cable cost low and is suitable for popularization and application.

Description

An aluminum alloy refractory medium voltage cable

technical field

The utility model relates to the field of cables, in particular to an aluminum alloy fire-resistant medium-voltage cable, which is especially suitable for 6-35KV power supply and distribution systems with fire-resistant requirements.

Background technique

6-35KV fire-resistant medium-voltage cables are required to ensure uniform distribution of the internal electric field and control the amount of partial discharge. Most of the conductor shielding + insulation + insulation shielding layers are extruded by three-layer co-extrusion, and then wrapped with copper tape to form a uniform electric field distribution. insulation shielding system. Therefore, fire-resistant medium-voltage cables are different from low-voltage cables of 1.8/3kV and below, and the fire-resistant layer cannot be set in the insulation shielding system.

Most of the existing fire-resistant cables use ceramic silicone rubber as the fire-resistant and heat-insulating layer. Although it is feasible in theory, it is not suitable for popularization and application due to high material cost and poor heat insulation effect.

At present, the common design of fire-resistant medium-voltage cables mostly uses copper as the conductor instead of aluminum alloy. The reason is that the melting point of aluminum is lower than the flame temperature of the fire-resistant test. The melting point of copper is only 660°C and it is easy to fuse, which leads to the failure of the test, while the melting point of copper is above 1083°C, so most fire-resistant cables choose copper. However, as a medium-voltage cable, if the temperature of the conductor rises to 660°C, the insulating layer and shielding layer have already been damaged, resulting in breakdown. Therefore, the key to restricting the medium-voltage fire resistance performance is the temperature resistance of the insulation and shielding layer, not the temperature resistance of the conductor. . In addition, the price of copper is about 1.5 times that of aluminum, and the cost is relatively high.

Therefore, in the prior art, there is a need for a solution with good fire resistance and low cost to solve this problem.

Utility model content

The purpose of the utility model is to provide an aluminum alloy fire-resistant medium-voltage cable to solve the problems raised in the background technology.

In order to achieve the above purpose, the utility model provides an aluminum alloy refractory medium voltage cable, which includes a cable core and an outer cladding wrapped outside the cable core. The cable core includes one or more insulated cores and ceramic fiber cotton filling Layer 6, the ceramic fiber cotton filling layer 6 is arranged between the insulated wire core and the outer cladding layer or between a plurality of insulated wire cores, the insulated wire core contains an aluminum alloy conductor 1, and the outer cladding layer includes The vitrified fiber tape wrapping layer 7 , the low-smoke and halogen-free oxygen barrier layer 8 , the vitrified silicone rubber band wrapping layer 9 and the vitrified polyolefin sheath layer 10 are arranged sequentially from the inside to the outside.

Further, the thickness of the vitrified fiber tape wrapping layer 7 is 5.5-6.5 mm.

Further, the thickness of the low-smoke zero-halogen oxygen barrier layer 8 is 2-3 mm.

Further, the thickness of the ceramicized silicone rubber tape used for winding the ceramicized silicon rubber tape around the cladding layer 9 is equal to 0.35-0.45mm, and the overlap rate when the tape is wound is 25-35%.

Further, the insulated wire core includes the aluminum alloy conductor 1 and the conductor shielding layer 2, the cross-linked polyethylene insulating layer 3, the insulating shielding layer 4 and the copper alloy conductor which are wrapped and arranged outside the aluminum alloy conductor in sequence from the inside to the outside. With shield 5.

Further, the aluminum alloy conductor is a duralumin wire with a conductivity not less than 63.1%, a tensile strength equal to 165-185 MPa and an elongation not less than 2%.

Beneficial effect:

The utility model enables the cable to achieve good thermal insulation and economic efficiency through the optimized setting of the cable core filling layer and the outer cladding layer. Within 90 minutes, the temperature of the outer layer flame transmitted to the cable insulation layer does not exceed 330°C. The insulation layer is less damaged, so it can withstand the test voltage and meet the requirements of TICW 8-2012 "Rated voltage 6kV to 35kV extruded insulation fire-resistant power cables".

The medium-voltage power cable of the utility model adopts high-conductivity duralumin wire instead of copper as a conductor, is light in weight and has good conductivity, low line loss, saves electric energy, has high strength and good creep resistance, and the outer cladding has high resistance. Flammability, the entire cable has good fire resistance, and all components meet the environmental protection requirements of the ROHS directive. When burning, it meets the characteristics of non-toxic, low smoke, and flame retardant. It is an environmentally friendly and energy-saving product, and the material consumption is small and the material price is low. , making the cost of the cable low and suitable for popularization and application.

In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. Below with reference to figure, the utility model is described in further detail.

Description of drawings

The accompanying drawings constituting a part of this application are used to provide a further understanding of the utility model, and the schematic embodiments of the utility model and their descriptions are used to explain the utility model, and do not constitute an improper limitation of the utility model. In the attached picture:

Fig. 1 is a cross-sectional structure diagram of an aluminum alloy fire-resistant medium-voltage cable in a preferred embodiment of the present invention.

In the figure: 1-aluminum alloy conductor, 2-conductor shielding layer, 3-XLPE insulation layer, 4-insulation shielding layer, 5-copper tape shielding layer, 6-ceramic fiber cotton filling layer, 7-ceramic fiber Tape wrapping, 8-low-smoke halogen-free oxygen barrier layer, 9-ceramic silicone rubber tape wrapping, 10-ceramic polyolefin sheath.

detailed description

The embodiments of the utility model will be described in detail below in conjunction with the accompanying drawings, but the utility model can be implemented in various ways defined and covered by the claims.

Referring to the aluminum alloy refractory medium-voltage cable in Fig. 1, the cable core includes a cable core and an outer cladding wrapped around the cable core. The cable core includes three insulated cores and a filling layer 6 of ceramic fiber cotton. The outer cladding is also arranged between three insulated wire cores. The conductor 1 in the insulated wire core is an aluminum alloy wire with a conductivity of not less than 63.1% (the specific composition and manufacturing method have been disclosed in Chinese Patent 2014108337850), and the outer cladding It includes a ceramic fiber tape wrapping layer 7, a low-smoke halogen-free oxygen barrier layer 8, a ceramic silicone rubber tape wrapping layer 9, and a ceramic polyolefin sheath layer 10, which are wrapped in sequence from the inside to the outside.

In this embodiment, the thickness of the vitrified fiber tape wrapping layer 7 is 6 mm.

In this embodiment, the thickness of the LSZH oxygen barrier layer 8 is 2.5mm.

In this embodiment, the thickness of the ceramic silicon rubber tape used to wind the ceramic silicon rubber tape around the cladding layer 9 is equal to 0.4mm, and the overlapping rate of the tape is 30%.

In this embodiment, the insulated wire core includes an aluminum alloy conductor 1 and a conductor shielding layer 2, a cross-linked polyethylene insulating layer 3, an insulating shielding layer 4, and a copper tape shielding layer that are sequentially wrapped and arranged outside the aluminum alloy conductor 1 from the inside to the outside. 5. Aluminum alloy with a conductivity of not less than 63.1% is used as the cable conductor, and the conductivity is more than 2% higher than that of conventional aluminum alloys (such as AA8030). Under the same specification, the power loss of the line is reduced, so as to achieve the purpose of energy saving.

The effect of main functional layer of the present utility model is respectively:

1. Ceramic fiber cotton filling layer 6 + ceramic fiber tape wrapping layer 7 as heat insulation layer

In the prior art, ceramicized silicon rubber is used as the heat insulation layer or cooling layer for fire-resistant medium-voltage cables. The actual cost is high, and the heat insulation effect is not good. The utility model uses ceramic fiber cotton to fill the gaps of the three cables, and then wraps them The ceramic fiber belt not only has good heat insulation effect, but also has low cost.

As a thermal insulation layer directly in contact with the cable shielding layer, its key role lies in good thermal resistance, that is, low thermal conductivity is required. The thermal conductivity of refractory ceramic fiber cotton is only 0.03W/m·k, and the thermal conductivity of ceramic fiber tape is 0.035W/m·k, which is lower than that of rock wool rope, asbestos rope, glass fiber, ceramic silicone rubber belt, and mica Belt, the price of ceramic fiber belt is 28 yuan/kg, the density is only 0.7kg/dm ³ , the unit price of ceramic silicon rubber is 45 yuan/kg, the density is 1.45kg/dm ³ , the unit price of synthetic mica belt is 30 yuan/kg, and the specific gravity is 1.28kg/dm ^3. The cost advantage is obvious and the weight is light. It can be seen that the selection of ceramic fiber as the heat insulation layer is superior to ceramic silicone rubber in terms of heat insulation effect, price and weight.

2. Extruded high-flame-retardant, low-smoke, halogen-free oxygen barrier material is the cooling oxygen barrier layer8

The high flame retardant low smoke halogen free oxygen barrier material is based on AL(OH) ₃ and polyolefin, the oxygen index is ≥ 45, decomposes crystal water at high temperature, lowers the temperature of the cable, and forms an aluminum oxide shell to isolate oxygen from entering. The thickness of the isolation layer is between 2 and 3mm, which can not only meet the performance requirements of oxygen insulation and fire prevention, but also meet the economical requirements.

3. The ceramic silicone rubber belt wraps around the cladding layer 9 to form an inner fire-blocking layer

Considering that the unit price of the material is relatively high, only one layer of 0.4 mm tape is overlapped and wrapped in this embodiment, and the overlap rate is 30%. Utilizing the characteristics of the material to quickly form a ceramic shell after being heated, it is used to prevent the flame from directly burning the cooling layer. The higher the flame temperature and the longer the burning time of the ceramic shell, the harder the fired ceramic-like armor body can effectively block the flame.

4. Extrude ceramic polyolefin sheath material to form outer sheath layer 10

The ceramic polyolefin sheath material forms the outer sheath, which usually protects the internal structure of the cable. When burning, it forms a ceramic shell, which together with the wrapped ceramic silicone rubber belt forms an inner and an outer fire barrier to isolate the flame. The sheath thickness is determined according to the product standard. The market unit price of this material is 30 yuan/kg, and its density and unit price are lower than those of vitrified silicone rubber.

The above are only preferred embodiments of the utility model, and are not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (6)

1. a kind of aluminium alloy fire-proof medium-voltage cable, it is characterised in that including cable core and the surrounding layer being wrapped in outside cable core, the cable Core includes one or more insulated wire cores and ceramic fiber cotton packed layer (6), and the ceramic fiber cotton packed layer (6) is arranged on absolutely Between edge core and surrounding layer or it is additionally arranged between more insulated wire cores, aluminium alloy conductor is included in the insulated wire cores (1), the surrounding layer includes wrapping up the ceramic fiber band lapping layer (7) of setting, low smoke and zero halogen oxygen barrier layer successively from inside to outside (8), Ceramic silicon rubber band lapping layer (9) and ceramic polyolefin sheath layer (10).

2. a kind of aluminium alloy fire-proof medium-voltage cable according to claim 1, it is characterised in that the insulated wire cores include institute State aluminium alloy conductor (1) and wrap up the conductor shield (2) being arranged on outside the aluminium alloy conductor successively from inside to outside, be crosslinked and gather Ethene insulating barrier (3), insulation screen (4) and copper strip shielding layer (5).

3. a kind of aluminium alloy fire-proof medium-voltage cable according to claim 2, it is characterised in that the aluminium alloy conductor is to lead Electric rate is not less than 2% hard aluminum wire not less than 63.1%, tensile strength equal to 165-185MPa and elongation percentage.

4. a kind of aluminium alloy fire-proof medium-voltage cable according to any one in claims 1 to 3, it is characterised in that described Thickness of the ceramic fiber with lapping layer (7) is 5.5~6.5mm.

5. a kind of aluminium alloy fire-proof medium-voltage cable according to any one in claims 1 to 3, it is characterised in that described The thickness of low smoke and zero halogen oxygen barrier layer (8) is 2~3mm.

6. a kind of aluminium alloy fire-proof medium-voltage cable according to any one in claims 1 to 3, it is characterised in that be used for The thickness of Ceramic silicon rubber belt of the Ceramic silicon rubber described in coiling with lapping layer (9) is equal to 0.35~0.45mm, belt Duplication during coiling is 25~35%.