CN221708449U - A new type of halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable - Google Patents

Abstract

The utility model relates to the field of power cables, and specifically to a new type of halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable, which includes a plurality of groups of cable cores and a cable sheath arranged outside the cable cores, wherein the cable cores include a conductor, a conductor shielding layer wrapped outside the conductor, an insulating layer wrapped outside the conductor shielding layer, and an insulating shielding layer wrapped outside the insulating layer, and also include a metal shielding mesh arranged outside the insulating shielding layer, and the cable sheath includes an inner flame-retardant layer, a ceramic fire-resistant layer, a fire-resistant heat-insulating layer, an armor layer and an outer sheath arranged in sequence from the inside to the outside. The utility model is composed of a cable core and a cable sheath, wherein the inner cable core provides good insulation performance, and the outer cable sheath provides good flame-retardant performance, thereby realizing the function of insulating internal heat, preventing the spread of flames, and avoiding the fire from becoming larger.

Description

A new type of halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable

Technical Field

The utility model relates to the technical field of power cables, in particular to a novel halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable.

Background Art

At present, the halogen-free low-smoke cables on the market are generally products with a withstand voltage of 0.6/1kV and below, and there are many types. With the continuous improvement of modern construction, electricity consumption has also continued to increase, and medium-voltage cables (with a withstand voltage of 3.6/6 to 26/35kV) have been widely used. However, the fire-resistant combustion performance of medium-voltage cables on the market cannot be guaranteed. In a fire, the power is often cut off first, which makes the entire back-end power outage, which will bring difficulties to fire fighting and escape.

In addition, the medium-voltage cables currently on the market will release thick black smoke and toxic and harmful gases such as hydrogen chloride gas during a fire, which will cause trapped people to have low visibility and inhale toxic gases. In severe cases, they will suffocate and cause significant losses.

Therefore, those skilled in the art provide a novel halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable to solve the problems raised in the above-mentioned background technology.

Utility Model Content

In order to solve the above technical problems, the utility model provides a novel halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable, which comprises a plurality of groups of cable cores and a cable sheath arranged outside the cable cores.

On the one hand, the cable core includes a conductor, a conductor shielding layer wrapped around the conductor, an insulating layer wrapped around the conductor shielding layer, and an insulating shielding layer wrapped around the insulating layer;

Among them, the conductor is formed by twisting multiple wire cores, and the conductor shielding layer is a shielding layer of semi-conductive material, and the conductor shielding layer is at the same potential as the conductor; an air gap is easily formed between the conductor and the insulating layer, and the surface of the conductor is not smooth, which will cause electric field concentration, so a conductor shielding layer is added on the surface of the conductor, which is at the same potential as the conductor and has good contact with the insulating layer, thereby avoiding local discharge between the conductor and the insulating layer.

Furthermore, the insulating layer is an XLPE layer, and the insulating shielding layer is a shielding layer of a semi-conductive material, which, on the one hand, protects the insulating core, and on the other hand, is in good contact with the insulating layer, and an equipotential is formed on the surface of the insulating layer, which can effectively avoid local discharge between the insulating layer and the cable sheath.

Preferably, the conductor shielding layer, the insulating layer and the insulating shielding layer are extruded at one time using a three-layer co-extrusion head, which can effectively avoid partial discharge caused by gaps in the conductors due to process factors caused by separate extrusion.

In the further elaborated scheme, a metal shielding mesh is also provided outside the insulating shielding layer. The metal shielding mesh is used to shield the electromagnetic field generated by the cable during operation within the insulating core to reduce electromagnetic interference to the outside world. At the same time, the fault current within the design range generated by the system is safely introduced into the grounding system to protect the safe operation of the system. The metal shielding mesh is composed of sparsely wound copper wire and reversely wound copper wire.

On the other hand, the cable sheath comprises an inner flame retardant layer, a ceramic fire-resistant layer, a fire-resistant heat-insulating layer, an armor layer and an outer sheath arranged in sequence from the inside to the outside, and the inner flame retardant layer is wrapped around the outside of the insulating shielding layer;

Preferably, the inner flame retardant layer is made of a glass fiber layer. Glass fiber is environmentally friendly and non-toxic, has good high temperature resistance and fire resistance, good flame retardant effect, and can form a three-dimensional mesh structure, which can improve the toughness and tensile resistance of the cable and make the cable have higher impact resistance.

Preferably, the ceramic refractory layer adopts ceramic halogen-free low-smoke polyolefin flame retardant refractory oxygen-insulating material. In the case of fire, it forms a hard armor after ablation, and a dense and uniform microporous ceramic will be generated on the cross section. The crusting speed is fast, and the shell is hard and dense, which can play a very good oxygen isolation, heat insulation and fire-blocking effect. In addition, the amount of smoke after combustion is small, and the toxicity of smoke is low. Compared with ordinary cables, the secondary harm to the human body is greatly reduced.

Preferably, the fire-resistant heat-insulating layer is made of a low-smoke halogen-free flame-retardant material with an oxygen index greater than 35%, and has good flame-retardant and oxygen-isolating functions.

Preferably, the armor layer adopts a wrapped double-layer galvanized steel belt armor layer, which can significantly block and isolate the flame, effectively prevent the flame from contacting the internal cable conductor, and is beneficial to enhancing the overall structural strength of the power cable.

Preferably, the outer sheath adopts a ceramicized halogen-free low-smoke polyolefin flame-retardant and fire-resistant sheath. After ablation, uniform ceramic micropores will be generated on the hard shell section. The dielectric strength of the ceramic armor is greater than 40KV/mm, and the volume resistivity is greater than 2×1018Ω•cm. It can be used as both a sheath layer and a fire-resistant and fire-resistant layer.

Preferably, a filling layer is provided between the inner flame retardant layer and the metal shielding mesh, and the filling layer is a halogen-free flame retardant filling rope.

Technical effects and advantages of the utility model:

The utility model is composed of a cable core and a cable sheath, and has good insulation and flame retardant properties. The internal cable core provides good insulation performance, and the external cable sheath provides good flame retardant performance, thereby realizing the function of insulating internal heat, preventing flames from spreading, and avoiding the fire from getting bigger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the composition structure of a novel halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable provided in an embodiment of the present application;

2 is a schematic diagram of a partial structure of a cable sheath in a novel halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable provided in an embodiment of the present application;

In the figure:

1. Cable core, 11. Conductor, 12. Conductor shielding layer, 13. Insulating layer, 14. Insulating shielding layer, 15. Metal shielding mesh;

2. Cable sheath, 21. Inner flame retardant layer, 22. Ceramic fire-resistant layer, 23. Fire-resistant insulation layer, 24. Armor layer, 25. Outer sheath;

3. Filling layer.

DETAILED DESCRIPTION

The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific purposes.

Example 1

Please refer to Figures 1 and 2. In this embodiment, a novel halogen-free, low-smoke, highly flame-retardant and fire-resistant medium-voltage power cable is provided, which includes a plurality of groups of cable cores 1 and a cable sheath 2 arranged outside the cable cores 1. The drawings of this scheme show an embodiment using three groups of cable cores 1, and the actual number is not limited thereto.

On one hand, the cable core 1 includes a conductor 11 , a conductor shielding layer 12 wrapped around the conductor 11 , an insulating layer 13 wrapped around the conductor shielding layer 12 , and an insulating shielding layer 14 wrapped around the insulating layer 13 .

In the three-layer composition, the conductor shielding layer 12, the insulating layer 13 and the insulating shielding layer 14 are extruded at one time using a three-layer co-extrusion head, which can effectively avoid the local discharge phenomenon caused by the gap of the conductor 11 due to the process factor caused by separate extrusion. The cable core 1 provides the cable with good insulation performance and achieves the purpose of heat insulation and fire resistance.

In addition, a metal shielding mesh 15 is provided outside the insulating shielding layer 14. The metal shielding mesh 15 is used to shield the electromagnetic field generated by the cable during operation within the insulating core to reduce electromagnetic interference to the outside world. At the same time, the fault current within the design range generated by the system is safely introduced into the grounding system to protect the safe operation of the system. The metal shielding mesh 15 is composed of sparsely wound copper wires and reversely wound copper wires.

On the other hand, the cable sheath 2 includes an inner flame retardant layer 21 , a ceramic fire-resistant layer 22 , a fire-resistant insulation layer 23 , an armor layer 24 and an outer sheath 25 which are arranged in sequence from the inside to the outside. The inner flame retardant layer 21 is wrapped around the outside of the metal shielding mesh 15 .

A filling layer 3 is provided between the inner flame retardant layer 21 and the metal shielding mesh 15 , and the filling layer 3 is a halogen-free flame retardant filling rope, which has good fire resistance and heat insulation properties, prevents high temperature from being transferred to the insulating layer 13 , and ensures the insulation performance of the cable core 1 .

Among them, the conductor 11 is formed by twisting multiple wire cores, the conductor shielding layer 12 is a shielding layer of semi-conductive material, and the conductor shielding layer 12 is at the same potential as the conductor 11; an air gap is easily formed between the conductor 11 and the insulating layer 13, and the surface of the conductor 11 is not smooth, which will cause electric field concentration, so a conductor shielding layer 12 is added on the surface of the conductor 11, which is at the same potential as the conductor 11 and has good contact with the insulating layer 13, thereby avoiding local discharge between the conductor 11 and the insulating layer 13.

Among them, the insulating layer 13 is an XLPE layer, and the insulating shielding layer 14 is a shielding layer of semi-conductive material. On the one hand, it plays a role in protecting the insulating core, and on the other hand, it is in good contact with the insulating layer 13, and an equipotential is formed on the surface of the insulating layer 13, which can effectively avoid local discharge between the insulating layer 13 and the cable sheath 2.

In the composition of the cable sheath 2, the inner flame retardant layer 21 is made of a glass fiber layer. The glass fiber is environmentally friendly and non-toxic, has good high temperature resistance and fire resistance, has a good flame retardant effect, and can form a three-dimensional mesh structure, which can improve the toughness and tensile resistance of the cable and make the cable have higher impact resistance.

The ceramic refractory layer 22 adopts ceramic halogen-free low-smoke polyolefin flame retardant refractory oxygen-isolating material. In the case of fire, it will form a hard armor after ablation, and the cross section will generate dense and uniform microporous ceramics. The crusting speed is fast, the shell is hard and dense, and it can play a very good oxygen isolation, heat insulation and fire-blocking effect. In addition, the amount of smoke after combustion is small, and the toxicity of smoke is low. Compared with ordinary cables, the secondary harm to the human body is greatly reduced.

The fire-resistant heat-insulating layer 23 is made of low-smoke halogen-free flame-retardant material with an oxygen index greater than 35%, and has good flame-retardant and oxygen-isolating functions.

The armor layer 24 is a wrapped double-layer galvanized steel belt armor layer 24, which can significantly block and isolate the flame, effectively prevent the flame from contacting the internal cable conductor 1, and is beneficial to enhancing the overall structural strength of the power cable.

Among them, the outer sheath 25 adopts a ceramicized halogen-free low-smoke polyolefin flame-retardant and fire-resistant sheath. After ablation, uniform ceramic micropores will be generated on the hard shell section. The dielectric strength of the ceramic armor is greater than 40KV/mm, and the volume resistivity is greater than 2×1018Ω•cm. It can be used as both a sheath layer and a fire-resistant and fire-resistant layer.

The outer cable sheath 2 provides good flame retardant properties, realizes the function of internal heat insulation, prevents the spread of flames, and avoids the fire from getting bigger, thereby achieving good flame retardant properties. At the same time, it produces halogen-free and low smoke when burning, which has less harm to the human body and high safety performance.

Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. Structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to conventional means in the field unless otherwise specified and limited.

Claims (10)

1. The utility model provides a novel there is not steamed low fire-retardant fire-resistant middling pressure power cable of cigarette height, includes that a plurality of groups of cables lead the core and locate the outside cable sheath of cable lead the core and constitute its characterized in that:

the cable guide core comprises a conductor, a conductor shielding layer wrapped outside the conductor, an insulating layer wrapped outside the conductor shielding layer and an insulating shielding layer wrapped outside the insulating layer;

The cable sheath comprises an inner flame retardant layer, a ceramic flame retardant layer, a flame-resistant heat insulation layer, an armor layer and an outer sheath which are sequentially arranged from inside to outside, and the inner flame retardant layer is wrapped outside the insulating shielding layer.

2. The novel halogen-free low-smoke high-flame-retardant fireproof medium-voltage power cable according to claim 1, wherein the conductor is formed by twisting a plurality of wire cores, the conductor shielding layer is a shielding layer made of a semiconductive material, and the conductor shielding layer is equipotential with the conductor.

3. The novel halogen-free low-smoke high-flame-retardant fireproof medium-voltage power cable according to claim 1, wherein the insulating layer is an XLPE layer, and the insulating shielding layer is a shielding layer made of semiconductive materials.

4. The novel halogen-free low smoke high flame retardant fire resistant medium voltage power cable according to claim 1, wherein the inner flame retardant layer is a glass fiber layer.

5. The novel halogen-free low-smoke high-flame-retardant fire-resistant medium-voltage power cable according to claim 1, wherein the ceramic fire-resistant layer is made of ceramic halogen-free low-smoke polyolefin, flame-retardant, fire-resistant and oxygen-resistant.

6. The novel halogen-free low-smoke high-flame-retardant fireproof medium-voltage power cable according to claim 1, wherein the fireproof heat-insulating layer is made of a low-smoke halogen-free flame-retardant material with an oxygen index of more than 35%.

7. The novel halogen-free low-smoke high-flame-retardant fire-resistant medium voltage power cable according to claim 1, wherein the armor layer is a double-layer galvanized steel tape armor layer.

8. The novel halogen-free low-smoke high-flame-retardant fire-resistant medium-voltage power cable according to claim 1, wherein the outer sheath is a ceramic halogen-free low-smoke polyolefin fire-retardant fire-resistant sheath.

9. The novel halogen-free low-smoke high-flame-retardant fireproof medium-voltage power cable according to claim 1, wherein a metal shielding net is further arranged outside the insulating shielding layer, the metal shielding net consists of loose-wound copper wires and reverse-wound copper wires, a filling layer is arranged between the inner resistance layer and the metal shielding net, and the filling layer is a halogen-free flame-retardant filling rope.

10. The novel halogen-free low-smoke high-flame-retardant fireproof medium-voltage power cable according to claim 1, wherein the conductor shielding layer, the insulating layer and the insulating shielding layer are formed by one-step extrusion molding.