CN204303435U - A kind of split isolation volume enlarging high pressure power cable of the insulation that bonds - Google Patents

Abstract

The utility model discloses a bonded and insulated split isolation capacity-increasing high-voltage power cable, which comprises a cable outer layer and a cable core arranged in the center of the cable outer layer. The cable core is composed of a plurality of split strands, and the split The strands are composed of multiple copper wires, the split strands are fan-shaped, and the multiple split strands surround the center of the cable to form a complete circle and cover the semi-conductive tape. There is insulating paper between the split strands, The copper wire is covered with insulating adhesive glue. The utility model divides the large-section conductor cable core into several parts which are insulated from each other, and coats a layer of insulating adhesive on each copper wire before twisting, so as to reduce the conductor AC caused by the skin effect to the greatest extent. The increase in resistance can effectively reduce the loss and heat generation of the conductor, increase the current carrying capacity of the conductor, and achieve the effect of energy saving.

Description

A bonded and insulated split-isolation capacity-increasing high-voltage power cable

technical field

The utility model relates to the technology of power cables.

Background technique

At present, for ultra-high voltage and large-capacity power transmission at home and abroad, cables with a cross-section of 1000mm ² , 1200mm ² or even larger to 2500mm ² are mostly used. The conductors of such large cross-section cables are prone to eddy currents during operation, which will cause the temperature of the conductor to rise and cause energy loss. . This is due to the existence of the skin effect in the AC system, the current carrying capacity in the conductor does not increase proportionally with the increase of the cable conductor cross section, but when the conductor diameter increases to a certain extent, the skin effect is serious, resulting in The AC effective resistance of the conductor, that is, the AC resistance, will be significantly greater than its DC resistance, so simply increasing the cross-section will lose its practicality and economy. Skin effect produces eddy currents in each wire, and proximity effect also produces eddy currents in each wire. Therefore, in reality, not only does eddy current exist in each wire, but also eddy current exists between wires if they are not insulated. For cable lines, the existence of skin effect and proximity effect will increase the AC resistance of the cable core, thereby reducing the allowable carrying capacity of the cable, that is, the cable wastes a large part of the transmission current.

Utility model content

The technical problem to be solved by the utility model is to provide a bonded and insulated split isolation and capacity-increasing high-voltage power cable, which can minimize the increase in the conductor AC resistance caused by the skin effect and effectively reduce the loss and heat generation of the conductor. Increase the ampacity of the conductor.

In order to solve the above-mentioned technical problems, the utility model adopts the following technical scheme: a bonded and insulated split isolation capacity-increasing high-voltage power cable, which includes a cable outer layer and a cable core located at the center of the cable outer layer, and the cable core is composed of multiple The split strands are composed of multiple copper wires. The split strands are fan-shaped. The multiple split strands surround the center of the cable to form a complete circle and cover the semi-conductive tape. The split strands Insulating paper is arranged between the strands, and the copper wire is covered with insulating adhesive.

Preferably, there are five fan-shaped split strands.

Preferably, the outer layer of the cable includes a semi-conductive inner shield, an insulating layer, a semi-conductive outer shield, a semi-conductive buffer water-blocking tape, an aluminum sheath, an asphalt anti-corrosion layer, an outer sheath, and a conductive layer from the center to the outside.

Preferably, the cross-sectional area of the power cable is ≥1000mm ² .

In order to minimize the increase of the conductor AC resistance caused by the skin effect, effectively reduce the loss and heat generation of the conductor, and increase the carrying capacity of the conductor, the utility model divides the conductor cable core with a large cross-section into several parts insulated from each other to form Split conductor, by selecting the best structure of the split conductor, the fan-shaped strands that are conducive to structural stability are selected through the pre-twisted 5-split structure, which is the most stable structure.

In order to further reduce the energy loss of large-section high-voltage cables and increase the carrying capacity of the cables, each conductor in the conductor structure is insulated. Because if the super-large cross-section cable conductor adopts a twisted and compacted structure, the skin effect coefficient of the conduction in the power transmission process will reach 54%; and if the split conductor structure (split isolated copper conductor) is used, the skin effect coefficient will drop to 26%; if each wire in the split conductor structure is insulated (insulation structure to prevent eddy current concentration effect), the electric heat loss of the conductor is reduced to 8%. Therefore, a layer of insulating adhesive is coated on each copper wire before stranding. The adhesive has high bonding strength and good toughness. Twisted conductor stranding adopts the method of layering and multi-roller pressing layer by layer, and the surface of the conductor that the adhesive glue always adheres to will not fall off or crack.

Since each wire in the split conductor structure is insulated (insulation structure for preventing eddy current concentration effect), the electric heat loss of the conductor is reduced to 8%. The surface of the divided conductor is smooth and round, which minimizes the increase in the AC resistance of the conductor caused by the skin effect, effectively reduces the loss and heat generation of the conductor, increases the carrying capacity of the conductor, and has the effect of saving energy.

Preheating the cable aluminum sheath before coating the asphalt anti-corrosion layer on the outer surface of the cable aluminum sheath can avoid the phenomenon of asphalt agglomeration and asphalt leakage caused by the low temperature of the aluminum sheath of the high-voltage cable.

The outer sheath extrusion process design adopts double-layer co-extrusion technology, and the outer sheath and the conductive layer are extruded at the same time. Due to the double-layer co-extrusion technology, the thickness of the conductive layer is uniform, and the bonding performance with the cable sheath is good, which ensures the reliability of the DC withstand voltage performance of the outer sheath. However, the conductive layer of the traditional process uses graphite coating, which is easy to lay. Falling off, polluting the production and laying site environment.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the utility model is further described:

Fig. 1 is a cross-sectional structure diagram of a power cable of the present invention.

Detailed ways

A bonded and insulated split isolation capacity-increasing high-voltage power cable, comprising a cable outer layer and a cable core arranged in the center of the cable outer layer, the cable core is composed of a plurality of split strands, and the split strands are composed of a plurality of Composed of copper wire 1, the split strands are fan-shaped, a plurality of split strands surround the center of the cable to form a full circle and cover the semi-conductive tape 4, insulating paper 3 is arranged between the split strands, and the The copper wire is covered with insulating adhesive 2, and the cross-sectional area of the power cable is ≥1000mm ² .

Specifically, the insulating paper is crepe insulating paper, and there are five fan-shaped split strands. The outer layer of the cable includes a semi-conductive inner shield 5, an insulating layer 6, a semi-conductive outer shield 7, a semi-conductive buffer water-blocking tape 8, an aluminum sheath 9, an asphalt anti-corrosion layer 10, an outer sheath 11, Conductive layer 12.

In order to minimize the increase in the AC resistance of the conductor caused by the skin effect, effectively reduce the loss and heat generation of the conductor, and increase the carrying capacity of the conductor, it is necessary to divide the large cross-section conductor into several parts that are insulated from each other to form a split conductor. The solution adopted by the utility model further reduces the energy loss of the large-section high-voltage cable by selecting the optimal structure of the divided conductor, and improves the carrying capacity of the cable, and each wire in the conductor structure is insulated. Because if the super-large cross-section cable conductor adopts a twisted and compacted structure, the skin effect coefficient of the conduction in the power transmission process will reach 54%; and if the split conductor structure (split isolated copper conductor) is used, the skin effect coefficient will drop to 26%.

If each wire in the divided conductor structure is insulated (insulation structure to prevent eddy current concentration effect), the electric heat loss of the conductor is reduced to 8%. Therefore, when determining the structure of the segmented conductor, the utility model has selected the fan-shaped strands that are conducive to structural stability through the pre-twisted 5-segment structure, which is the most stable structure designed by the utility model. For this reason, a layer of insulating adhesive glue is coated on each copper wire before stranding. The adhesive glue has high bonding strength and good toughness, and the adhesive glue will not crack and fall off after being squeezed and twisted. Due to the coating of a layer of insulating adhesive, each wire in the divided conductor structure is insulated (insulation structure for preventing eddy current concentration effect), and the electric heat loss of the conductor is reduced to 8%. The surface of the divided conductor is smooth and round, which minimizes the increase in the AC resistance of the conductor caused by the skin effect, effectively reduces the loss and heat generation of the conductor, increases the carrying capacity of the conductor, and has the effect of saving energy; the fan-shaped pre-twisted conductor is stranded Using the method of layering and multi-roller pressing layer by layer, the conductor surface that the adhesive glue always adheres to will not fall off or crack, and the insulating coating layer can be vulcanized at a temperature of 300°C during the cross-linking production process. The normal operating state of the cable at a maximum temperature of 90°C.

The cabling process of split conductors is the same as that of conventional large-section conductors. The main process includes the following steps: Copper conductor continuous drawing-wire cleaning-insulation adhesive coating and drying-sector strand stranding ——Split conductors into cables——Cross-linked three-layer co-extrusion——Drying room degassing——Wrapping buffer tape——Extruded aluminum sheath——Coating bitumen anti-corrosion layer——Extruding outer sheath and conductive layer --test.

In addition, preheating the aluminum sheath before coating the aluminum sheath with an asphalt anti-corrosion layer can avoid the phenomenon of asphalt agglomeration and asphalt leakage caused by the low temperature of the aluminum sheath of the high-voltage cable; the outer sheath extrusion process design Using double-layer co-extrusion technology, the outer sheath and the conductive layer are extruded at the same time, so that the thickness of the conductive layer is uniform, and the bonding performance with the cable sheath is good, ensuring the reliability of the DC withstand voltage performance of the outer sheath, while the traditional one The conductive layer of the process is coated with graphite, which is easy to fall off during laying, polluting the production and laying site environment, and has an environmental protection effect.

Claims (3)

1. A bonded and insulated split isolation capacity-increasing high-voltage power cable, comprising a cable outer layer and a cable core located at the center of the cable outer layer, the cable core is composed of a plurality of split strands, and the split strands are composed of Composed of a plurality of copper wires, characterized in that: the split strands are fan-shaped, a plurality of split strands surround the center of the cable to form a complete circle and cover the semi-conductive tape, and insulating paper is arranged between the split strands , the copper wire is covered with an insulating adhesive. 2. The bonded and insulated split-isolation and capacity-increasing high-voltage power cable according to claim 1, wherein there are five fan-shaped split strands. 3 . The bonded and insulated split-isolation and capacity-increasing high-voltage power cable according to claim 1 , wherein the cross-sectional area of the power cable is ≥1000 mm ² .