CN205140539U - Fire -retardant flexible high voltage DC cable of using in tunnel that blocks water - Google Patents

Abstract

The utility model discloses a flame-retardant and water-resistance flexible DC high-voltage cable used in tunnels, which comprises a cable water-resistance conductor, a conductor shielding layer, an insulation layer, an insulation shielding layer, a semiconductive resistance water buffer layer, a metal sheath and an outer sheath. layer; the cable water-blocking conductor is composed of several water-blocking conductors, and each water-blocking conductor is provided with a conductor shielding layer, and an insulating layer is provided outside the conductor shielding layer, and an insulating shielding layer is provided outside the insulating layer layer, the insulating shielding layer is provided with a semiconductive resistance water buffer layer, the semiconductive resistance water buffer layer is provided with a metal sheath, and the metal sheath is provided with an outer sheath. The utility model is safe and reliable in operation, can meet the requirements of relevant norms, and can be widely used in tunnel laying places that require fire and water resistance.

Description

A flame-retardant and water-resistant flexible DC high-voltage cable used in tunnels

technical field

The utility model relates to a flexible DC cable, in particular to a flame-retardant and water-resistant flexible DC high-voltage cable suitable for use in tunnels.

Background technique

Flexible DC transmission technology is a new type of DC transmission technology based on voltage source commutation technology (VSC), which has the advantages of low line cost, low line loss, stable system, flexible control of active power and reactive power when transmitting the same transmission power, Reliable operation, convenient phased construction and capacity expansion and other advantages, so it has received more and more attention worldwide. At present, the highest voltage level of the existing flexible DC transmission projects in the world is ±320kV. Only a few international giant cable companies have mastered the production, manufacturing and laying technology of ultra-high voltage DC cables. Therefore, domestic cable manufacturers urgently need to break through overseas Market monopoly, developed a series of ultra-high voltage flexible DC cables with independent intellectual property rights.

Conventional laying methods of high-voltage cables include direct burial laying, pipe laying, cable trench laying and tunnel laying. Different laying methods have different requirements for the structure and performance of cables. Cable tunnel laying has the advantages of strong line transmission capacity, small footprint, high space utilization rate, and easy maintenance. However, the cable tunnel is also a high-risk place for fires. In the event of a fire, the temperature inside the tunnel is relatively high, the cables tend to burn continuously, the fire develops more rapidly, the cable structure may be seriously damaged, and it is easy to cause large-scale power outages. less, it will cause greater difficulty in fire fighting. Therefore, based on the fire protection requirements in the tunnel, the outer sheath of the cable is required to have excellent flame retardancy. At the same time, most of the cable tunnels are in the environment of water seepage or high air humidity, so the cable structure is required to have good water resistance performance, so as to reduce the risk of electrical breakdown caused by the generation of water branches in the cable.

Currently commonly used extruded outer sheath materials for cables include polyethylene (PE) and polyvinyl chloride (PVC). The branched chain and cross-linking phenomenon will produce highly active chemical free radicals during combustion to further promote the combustion. Therefore, ordinary PE-sheathed cables not only cannot self-extinguish when exposed to open flames, but also have a very fast horizontal flame delay. Fast, so it is not suitable for the outer sheath material of high-voltage cables laid in tunnels. At present, flame retardant PVC sheathed cables are widely used in projects with flame retardant requirements. Compared with PE, PVC has better flame retardant properties. The reason is related to the role of chlorine atoms in its molecular structure. Without adding flame retardants Under the premise that it has an oxygen index of not less than 27, it can pass GB/T18380.35-2008 "Combustion Tests for Electric and Optical Cables Under Flame Conditions Part 35: Vertically Installed Bundled Wire and Cable Flame Vertical Spread Test Category C" For the specified Class C bunching combustion test, the oxygen index after adding flame retardant exceeds 30, and it can pass the Class A bunching combustion test. However, considering that polyvinyl chloride will precipitate toxic gases such as hydrogen chloride when it is burned, which will affect human health and even cause casualties, PVC is gradually eliminated as the outer sheath material for laying high-voltage cables in domestic tunnels.

The flame-retardant polyethylene material introduces an additive flame retardant into the polyethylene matrix material by physical blending to play a flame-retardant role. The doped polyethylene material has good flame-retardant properties and can meet the requirements of high-voltage cables in tunnels. Flame retardant requirements used in

Utility model content

Purpose of the utility model: The purpose of this utility model is to solve the deficiencies in the prior art and provide a flame-retardant and water-resistant flexible DC high-voltage cable suitable for use in tunnels, which is safe and reliable in operation and can meet the requirements of relevant specifications.

Technical solution: A flame-retardant and water-resistant flexible DC high-voltage cable used in tunnels according to the utility model, including cable water-resistant conductors, conductor shielding layers, insulating layers, insulating shielding layers, semi-conductive resistance water buffer layers, metal shielding layer and outer sheath; the cable water-blocking conductor is composed of several water-blocking conductors, and each water-blocking conductor is provided with a conductor shielding layer, and the conductor shielding layer is provided with an insulating layer, and the insulating layer is An insulating shielding layer is provided, and a semiconducting resistance water buffer layer is arranged on the outside of the insulating shielding layer, and a metal sheath is arranged on the outside of the semiconducting resistance water buffer layer, and an outer sheath is arranged on the outside of the metal sheathing layer.

Further, the water blocking conductor is one of annealed copper conductor, aluminum or aluminum alloy conductor.

Further, the conductor shielding layer adopts an extruded semiconductive layer or a combination of a semiconductive tape and an extruded semiconductive layer.

Further, the insulating layer is made of ultra-clean thermosetting cross-linked polyethylene insulating material specially used for DC cables.

Further, the insulating shielding layer is made of a semiconducting material specially used for DC cables with ultra-smooth performance, high electrical conductivity and thermosetting properties.

Further, the semiconductive resistance water buffer layer is made of a multi-layer semiconductive resistance water buffer tape.

Further, the semiconductive resistance water buffer layer is made of at least four layers of semiconductive resistance water buffer tapes with a thickness of 1.0-5.0 mm.

Further, the metal sheath adopts one of corrugated aluminum sheath or extruded lead sheath.

Further, the outer sheath adopts a flame-retardant polyethylene material that is directly extruded on the metal sheath.

Beneficial effects: the insulating layer of the utility model adopts the special cross-linked polyethylene insulating material for DC cables, so that the utility model meets the requirements of the new DC transmission technology based on the voltage source commutation technology (VSC); The conductive and water-resistant buffer layer makes the utility model have excellent longitudinal water-blocking performance; the use of flame-retardant polyethylene material to extrude and process the outer sheath of the cable makes the utility model not only have better flame-retardant performance, but also greatly reduces the The PVC sheath will produce a large amount of toxic gas hazards in the event of a fire, and the thickness of the outer sheath can be adjusted according to the specific needs of the product to meet the requirements of different levels of flame retardant performance of the cable, and can be widely used in tunnel laying.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the utility model.

detailed description

As shown in Figure 1, a flame-retardant and water-resistant flexible DC high-voltage cable used in a tunnel includes a cable water-resistant conductor 1, a conductor shielding layer 2, an insulating layer 3, an insulating shielding layer 4, a semiconducting resistance water buffer layer 5, A metal sheath 6 and an outer sheath 7; the cable water-blocking conductor 1 is composed of several water-blocking conductors, and each water-blocking conductor is provided with a conductor shielding layer 2, and the conductor shielding layer 2 is provided with an insulating layer 3, the insulating layer 3 is provided with an insulating shielding layer 4, the insulating shielding layer 4 is provided with a semiconductive resistance water buffer layer 5, and the semiconductive resistance water buffer layer 5 is provided with a metal sheath 6, The metal sheath 6 is provided with an outer sheath 7 .

As a further optimization of the above technical solution, the water blocking conductor is one of annealed copper conductor, aluminum or aluminum alloy conductor. The conductor shielding layer 2 is an extruded semiconductive layer or a combination of a semiconductive tape and an extruded semiconductive layer. The insulating layer 3 is made of ultra-clean thermosetting cross-linked polyethylene insulating material specially used for DC cables. The insulating shielding layer 4 is made of a semi-conductive material specially used for DC cables with ultra-smooth performance, high electrical conductivity and thermosetting properties. The semiconductive resistance water buffer layer 5 is made of at least four layers of semiconductive resistance water buffer tapes with a thickness of 1.0-5.0 mm. The metal sheath 6 is either a corrugated aluminum sheath or an extruded lead sheath.

The above is a detailed description of an embodiment of the utility model, but the content is only a preferred embodiment of the utility model, and cannot be considered as limiting the implementation scope of the utility model. All equal changes and improvements made according to the application scope of the utility model should not be excluded from the protection scope of the utility model.

Claims (9)

1. the fire-retardant flexible direct current high-tension cable that blocks water applied in tunnel, is characterized in that: comprise cable water-blocking conductor (1), conductor shield (2), insulating barrier (3), insulation screen (4), semiconductive water-blocking buffer layer (5), metal sheath (6) and outer jacket (7); Described cable water-blocking conductor (1) is made up of some water-blocking conductors, and be provided with conductor shield (2) outside every root water-blocking conductor, insulating barrier (3) is provided with outside described conductor shield (2), insulation screen (4) is provided with outside described insulating barrier (3), semiconductive water-blocking buffer layer (5) is provided with outside described insulation screen (4), be provided with metal sheath (6) outside described semiconductive water-blocking buffer layer (5), outside described metal sheath (6), be provided with outer jacket (7).

2. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: described water-blocking conductor adopts the one in annealed copper conductor, aluminum or aluminum alloy conductor.

3. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: described conductor shield (2) adopts and extrudes semi-conductive layer or adopt semiconductive band and extrude semi-conductive layer and combine.

4. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: described insulating barrier (3) adopts direct current cables special ultra-clean thermoset crosslink polyethylene Insulation Material to make.

5. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: described insulation screen (4) adopts the special material of partly leading of direct current cables with ultra-smooth performance, high conduction performance and thermosetting property to make.

6. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: described semiconductive water-blocking buffer layer (5) is blocked water by multilayer semiconductive, and buffer strip is wrapped to be made.

7. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 6, is characterized in that: the semiconductive that described semiconductive water-blocking buffer layer (5) is 1.0-5.0mm by least four layer thicknesses blocks water, and buffer strip is wrapped to be made.

8. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: the one that described metal sheath (6) adopts aluminium embossed sheath or extrudes in lead sheath.

9. the fire-retardant flexible direct current high-tension cable that blocks water applied in a kind of tunnel according to claim 1, is characterized in that: described outer jacket (7) adopts the fire-retardant polyethylene material be directly extruded on described metal sheath (6).