KR20140094096A - mica tape and fire resistant cable including the same - Google Patents

Abstract

Disclosed are a mica tape and a fire resistant cable including the same. A mica tape according to the present invention and a fire resistant cable including the same, improve productivity and reliability by the process simplification of the fire resistant cable, make a compact cable, maintain the same or improved fire resistant performance, and improve the strand unravelment phenomenon of the mica tape to remove the application of an additional PE tape. Also, a high bonding force is obtained by using an adhesive which makes the mica layer of the mica tape agglomerate and an adhesive which combines the mica layer and a base layer. The adhesives are made of the same material.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a mica tape,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mica tape and a refractory cable including the same, and more particularly, to a mica tape and a refractory cable including the same, which can improve productivity and reliability and increase fire resistance.

In recent years, a major issue in the cable manufacturing industry has been to improve cable behavior and performance in extreme temperature conditions, particularly in the face of fire. For safety, it is essential to delay the spread of flames and to maximize the ability of the cables to withstand flames.

As the fire-resistance of the cable is improved, the power-up time of the cable can be kept longer in the event of a fire, thereby extending the sprinkler operation time, delaying the expansion of the fire, It is possible to extend the time required to evacuate people or to place appropriate fire extinguishing means.

The demand for fire resistance is gradually increasing. Especially, cable products used in marine and offshore plants and building infrastructures require high fire resistance characteristics. In the event of a fire in a plant or building, a fireproof cable is required to keep the emergency power supply of the core facility, fire alarm, sprinkler, and other fire fighting / disaster prevention systems in operation for a minimum of time to escape and evacuate personnel.

The refractory layer is made by winding a Mica tape with high heat resistance and maintaining the cable function for a certain period of time even at a high temperature of 700 ~ 950 ℃. . At this time, the mica tape is made by bonding the mica powder to glass cloth or PE (polyethylene) tape. In case of fire, even if the insulator is burned, the conductor is wrapped around and serves as an insulator.

As shown in FIG. 1A, the first-generation mica tape 10 is formed by laminating a mica layer 13 on a base layer 11 made of a PE tape, and a second- The mica tape 20 is manufactured by laminating a mica layer 23 on a base layer 21 made of glass cloth as shown in FIG. 2A.

As shown in FIG. 1C, the third generation mica tape 30 is formed by laminating a mica layer 33 on a base layer 31 formed by mixing mica powder with glass fibers.

The first-generation mica tape 10 is melted at about 150 캜 of the base layer 11 made of a PE tape, so that there is a problem that the first-generation mica tape 10 is broken when the mica layer to be insulated acts on the base layer 11.

The second generation mica tape 20 which has been supplemented with the base layer 21 made of glass fiber developed to withstand a temperature of about 730 ° C for 1 to 2 hours, Has been improved to withstand a fire resistance performance of about 2 hours at a temperature of about 950 ° C.

However, since the third-generation mica tape 30 is formed by mixing the glass fiber (glass cloth) and the mica powder in forming the base layer 31, there is a problem that the manufacturing process becomes complicated.

When the glass fiber and the mica powder are mixed with the base layer 31 as in the third generation mica tape 30, the third glass mica tape 30 is applied to form a refractory layer. In the case of taping, There is a disadvantage in that the mica powder attached to the fiber is dropped by the friction, and at the same time, the loosening of the glass fiber is promoted.

Further, there is a problem in that homogeneity of the extrusion of the insulator is problematic due to the phenomenon that the glass fiber is caught in the insulating dies when the insulator is formed due to the annealing.

 In order to solve this problem, the PE tape which is not used at the time of applying the second-generation mica tape 20 should be additionally wound on the mica layer 33 of the third-generation mica tape 30. If a single PE tape is applied, It is damaged by the mica of the mica layer (33) while being wound, and it causes the failure of the insulation process, and therefore, it is necessary to wrap it in two or more layers. Therefore, the cable manufacturing process becomes complicated and the productivity is lowered.

Accordingly, a need has arisen for a mica tape capable of solving these problems, improving productivity and reliability, and improving fire resistance performance.

Embodiments of the present invention seek to improve productivity and reliability through simplified processes of refractory cables and to maintain the same or improved refractor performance while making the cables compact.

In addition, the annealing phenomenon of the mica tape is improved, so that the application of additional PE tape is not necessary.

In addition, a high adhesive force is exerted by using an adhesive for binding the inside of the mica layer of the mica tape and an adhesive for bonding the mica layer and the base layer with the same material.

According to an aspect of the present invention, there is provided a mica tape including a base layer made of basalt fiber and a mica layer made of a mica laminated on the base layer.

The adhesive used for forming the mica layer and the adhesive used for the adhesive surface of the mica layer and the base layer may be the same.

In addition, a multi-layer structure in which at least one of the base layer and the mica layer is alternately stacked two or more times.

According to another aspect of the present invention, there is provided a semiconductor device comprising a conductor, an insulating layer formed outside the conductor, and a refractory layer that performs the function of protecting and insulating the conductor in the event of a fire, wherein the refractory layer includes a base layer made of basalt fiber A refractory cable made of a mica tape can be provided.

Here, the refractory layer may be formed directly on the conductor.

The refractory cable of the present invention includes a first semiconductive layer formed adjacent to the conductor between the conductor and the insulating layer, a second semiconductive layer formed outside the insulating layer, and a second semiconductive layer formed outside the second semiconductive layer And the refractory layer may be formed between the insulating layer and the second semiconductive layer.

Further, the refractory cable of the present invention may further comprise a second insulation layer provided between the refractory layer and the second semiconductive layer.

Embodiments of the present invention can improve productivity and reliability by simplifying the process of the refractory cable, while maintaining the same or improved refractor performance while making the cable compact.

In addition, it is possible to improve the releasing phenomenon of the mica tape so that the application of the additional PE tape is not required.

In addition, a high adhesive force can be exhibited by using an adhesive for binding the inside of the mica layer of the mica tape and an adhesive for bonding the mica layer and the base layer with the same material.

1 is a cross-sectional view showing the structure of a conventional first to third generation mica tapes
2 is a cross-sectional view illustrating the structure of a mica tape according to an embodiment of the present invention.
3 is a cross-sectional view showing modifications of a mica tape according to an embodiment of the present invention
4 is a cross-sectional view of a single-phase low-pressure fireproof cable according to an embodiment of the present invention.
5 is a cross-sectional view of a three-phase low-pressure fireproof cable according to an embodiment of the present invention.
6 is a cross-sectional view of a single-phase high-pressure fireproof cable according to an embodiment of the present invention
7 is a cross-sectional view of a three-phase high-pressure fireproof cable according to an embodiment of the present invention
8 is a cross-sectional view of a single-phase high-pressure fireproof cable according to another embodiment of the present invention
9 is a cross-sectional view of a three-phase high-pressure fireproof cable according to another embodiment of the present invention
10 is a view showing a structural difference before and after forming a second insulation layer in a high-voltage fireproof cable according to another embodiment of the present invention
11 is a diagram showing a change in electric field intensity according to a distance from a conductor

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification.

FIG. 2 is a cross-sectional view illustrating a structure of a mica tape according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view illustrating modifications of a mica tape according to an embodiment of the present invention.

2 to 3, a mica tape 40 according to an embodiment of the present invention includes a base layer 41 made of basalt cloth and a mica layer 41 formed on the base layer 41 And a mica layer 43 made of MICA.

As described above, in the case of mixing the glass fiber with the mica powder as the base layer 41, there is a problem that the glass fiber is loosened and the productivity is lowered due to the taping process which is additionally applied to solve the problem. A basalt cloth is used as the base layer 41. [

The fibrousization process of basalt is very similar to that of glass. Specifically, the raw material is melted and then transported through a feed pipe made of an alloy of platinum and rhodium to the spinneret, and the melt is pushed through the nozzle located at its end through hydrodynamic pressure Method is used.

Basalt fibers are dark colored with a lot of oxides, and their chemical composition depends on the viscosity of the melt, the temperature of the process, and so on. Basalt fibers are not only high in melting point, they are cheap and rich in raw materials.

When the base layer 41 is formed using such a basalt fiber, it is possible to maintain a sufficient refractory performance without further mixing of the mica powder and improve the annealing phenomenon. Further, since the PE tape is not additionally used on the mica tape 40, the cable can be manufactured more compactly, and the productivity can be improved by the reduction of the process.

The adhesive used for forming the mica layer 43 and the adhesive used for bonding the mica layer 43 and the base layer 41 may be the same.

The conventional mica tape 40 has two kinds of adhesives for binding the mica in the mica layer 43 and an adhesive for bonding the mica layer 43 and the glass fiber used as the base layer 41, Was inevitable because of the large difference in the components.

However, since the basalt fiber is composed of a component similar to mica, an adhesive material that binds the inside of the mica layer 43 and an adhesive material of the same material are used for bonding the base layer 41 made of the mica layer 43 and the basalt fiber So that a higher adhesion can be exhibited to improve the structural stability.

Meanwhile, the mica tape 40 according to the present invention may have a multi-layer structure in which at least one of the base layer 41 and the mica layer 43 is alternately stacked more than once. The mica tape 40 can be manufactured by further forming a base layer 41 on the base layer 41 and the mica layer 43 as shown in Fig. 3 (a), for example.

3 (b), the mica layer 43, the base layer 41, and the mica layer 43 may be stacked in this order, and as shown in FIG. 3 (c) 41, the mica layer 43, the base layer 41, and the mica layer 43 are alternately stacked to form the mica tape 40. [

As described above, the mica tape 40 may be deformed in various forms other than the two-layer structure of the basic base layer 41 and the mica layer 43, and at least one of the base layer 41 and the mica layer 43 may be formed twice Layer structure in which the layers are stacked alternately so that the structural stability as well as the fire resistance performance can be improved.

<Table 1>

Table 1 compares the performance of a mica tape having a base layer mixed with a glass fiber and a mica powder and a mica tape having a base layer using a basalt fiber.

As shown in Table 1, the mica tape having the base layer using the basalt fiber has improved physical properties such as tensile strength, elastic modulus and elongation, compared to the case where the glass fiber is applied, and the actual use temperature is 650 ° C It is possible to improve the fire resistance characteristics. Also, since the melting point is about 1450 ° C higher than that of glass fiber by about 300 ° C, there is an advantage that the fire resistance performance of the cable can be maintained for a long time under extreme conditions such as fire.

FIG. 4 is a sectional view of a single-phase low-pressure fireproof cable according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view of a three-phase low-pressure fireproof cable according to an embodiment of the present invention.

2 to 5, a refractory cable 100 according to an embodiment of the present invention includes a conductor 111, an insulation layer 113 formed outside the conductor 111, 111 and a refractory layer 114 that performs insulation and protection functions. The refractory layer 114 may be a mica tape 40 including a base layer 41 of basalt fiber.

The conductor 111 may be a Class 2 or Class 5 conductor satisfying the IEC 60228 standard.

The insulating layer 113 is made of a material having insulating and impact resistance properties and covers and protects the conductor 111 and insulates the inside of the conductor from the outside, thereby preventing current from flowing out of the cable. The insulating layer 113 may be formed of a material selected from the group consisting of silicone rubber, cross-linked polyethylene (XLPE), crosslinked polyolefin (XLPO), ethylene-propylene rubber (EPR) A polymer such as high ethylene-propylene rubber (EPR), polyvinyl chloride (PVC), and the like, and a mixture thereof.

The refractory layer 114 may be formed by winding one or more layers of a mica tape 40 including a base layer 41 made of basalt fiber and a mica layer 43 formed thereon. Of course, the mica tape 40 of the modified embodiment shown in Fig. 3 can also be applied.

On the other hand, the refractory layer 114 may be formed on the conductor 111 directly. The refractory cable 100 shown in FIG. 4 is used for a low voltage of 3 kV or less. The refractory cable 100 satisfies electrical characteristics with only one layer of insulation on the conductor 111, and the refractory layer 114 is formed on the conductor 111 It is possible to exhibit the refractory performance and electrical characteristics of the cable without the problem of partial discharge or dielectric breakdown.

Here, the conductor 111, the refractory layer 114, and the insulating layer 113 constitute the cable core 110.

The inner sheath layer 120 may be formed on the outer side of the cable core 110. The inner sheath layer 120 may be made of polyvinyl chloride (PVC), which has high impact resistance and is halogen- , Polychloroprene rubber (CR), chlorosulfonated polyethylene (CSPE), chlorinated polyethylene (CPE), ethylene vinyl acetate (EVA) It can be applied in the form of an extruded layer.

The outer layer 130 is formed on the outer side of the inner sheath layer 120. The outer layer 130 may be formed of a metal material such as copper, aluminum, iron, copper alloy, aluminum alloy, Wire or the like.

The outer sheath layer 140 is formed on the outer side of the sheath layer 130. The outer sheath layer 140 has a high impact resistance and is halogen free Polyvinyl chloride (PVC), polychloroprene rubber (CR), chlorosulphonated polyethylene (CSPE), chlorinated polyethylene (CPE), ethylene vinyl acetate acetate; EVA), or a mixture of these, in the form of an extruded layer, which serves to protect the cable from external impacts and corrosion.

The structure of the inner sheath layer 120, the sheath layer 130, and the outer sheath layer 140 may vary depending on the use of the cable.

The low-pressure fire-resisting cable 100 may be a single core product made up of one cable core 110 as shown in FIG. 4 or a multi-core product made up of two or more cores as shown in FIG. 5 .

In the case of a multi-core product, a plurality of cable cores 110 are gathered at a predetermined pitch, and then the filler 150 is applied to the pores. Then, the inner sheath layer 120, the outer sheath layer 130, (140) may be formed to complete the product. The low-pressure fireproof cable 100 shown in FIG. 5 is a three-phase cable having three cable cores 110 as an example.

6 is a cross-sectional view of a single-phase high-pressure fireproof cable according to one embodiment of the present invention, and FIG. 7 is a sectional view of a three-phase high-pressure fireproof cable according to an embodiment of the present invention.

Referring to FIGS. 2, 3, 6, and 7, the refractory cable according to an embodiment of the present invention includes a conductor 111, a first semiconductive layer 112 formed on the outside of the conductor 111, An insulating layer 113 formed outside the first semiconductive layer 112 and a second semiconductive layer 115 formed outside the insulating layer 113. The second semiconductive layer 115 is formed outside the second semiconductive layer 115, And a refractory layer 114 provided between the insulating layer 113 and the second semiconductive layer 115. The shielding layer 116 may be formed of a silicon carbide layer,

The refractory cable shown in this embodiment corresponds to a refractory cable for medium pressure or high pressure.

The conductor 111 may be a Class 2 or Class 5 conductor satisfying the IEC 60228 standard. The first semiconductive layer 112 formed on the outside of the conductor 111 may be formed by extruding a semiconductive compound or by winding a semiconductive tape and applying them simultaneously to form a composite layer.

The first semiconductive layer 112 is an internal semiconductive layer. The first semiconductive layer 112 uniformizes the charge distribution on the surface of the conductor so as to alleviate the electric field concentration inside the cable. The gap between the conductor and the insulator is filled to minimize deterioration of the insulator by ionization Can play a role.

The insulating layer 113 is made of a material having insulating and impact resistance properties and covers and protects the conductor 111 and insulates the inside of the conductor from the outside, thereby preventing current from flowing out of the cable. The insulating layer 113 may be formed of a material selected from the group consisting of silicone rubber, cross-linked polyethylene (XLPE), crosslinked polyolefin (XLPO), ethylene-propylene rubber (EPR) A polymer such as high ethylene-propylene rubber (EPR), polyvinyl chloride (PVC), and the like, and a mixture thereof.

The second semiconductive layer 115 formed outside the insulating layer 113 is an external semiconductive layer. The semiconductive compound is formed by extruding a semiconductive compound or by winding a semiconductive tape in the same manner as the inner semiconductive layer. It is also possible to do.

The second semiconductive layer 115 serves to equalize electrical stress in the insulator and to minimize external corona.

The shielding layer 116 may be formed of a metal tape or a metal braid using a material such as copper, aluminum and a copper alloy or an aluminum alloy. The shielding layer 116 must be in contact with the second semiconductive layer 115 because if the shielding layer 116 and the second semiconductive layer 115 are not in contact with each other, .

The refractory layer 114 may be formed by winding one or more layers of a mica tape 40 including a base layer 41 made of basalt fiber and a mica layer 43 formed thereon. Of course, the mica tape 40 of the modified embodiment shown in Fig. 3 can also be applied. In this case, the number of windings may vary depending on required fire resistance performance, cable structure, and use, but in general, it is preferable to wind at least twice to realize basic fire resistance performance.

In the meantime, it is preferable that the refractory layer 114 is provided between the insulating layer 113 and the second semiconductive layer 115 in the refractory cable for medium or high voltage according to an embodiment of the present invention. As the refractory layer 114 is closer to the conductor 111, there is a high possibility that flexure and voids generated after the winding of the mica tape 40 are close to the conductor 111, that is, in a place where the electric field is large. In the cable, a problem of partial discharge (PD) may occur.

When a mica tape is formed between the first semiconductive layer 112 and the insulating layer 113, the surface between the first semiconductive layer 112 and the insulating layer 113 is relatively non-smooth, There is a problem that the value increases or insulation breakdown can easily occur.

A short between the conductor 111 and the shielding layer 116 may occur due to the burning of the insulating layer 113 at a high temperature in the event of a fire so that the refractory layer 114 is formed inside the shielding layer 116 So that the insulating layer 113 must be formed.

As described above, since the second semiconductive layer 115 and the shielding layer 116 are located adjacent to each other due to the grounding problem, it is possible to satisfy both of the above conditions and the electrical characteristics The refractory layer 114 is preferably located between the insulating layer 113 and the second semiconductive layer 115 to satisfy the fire resistance performance.

Therefore, unlike the case where the refractory layer 114 is formed on the outside of the conductor 111 or outside the first semiconductive layer 112 without worrying about the electrical characteristics and the structural characteristics in the low-voltage cable, in the refractory cable for medium or high- By forming the layer 114 between the insulating layer 113 and the second semiconductive layer 115, both the electrical characteristics and the refractory characteristics can be satisfied.

As a result, since the refractory layer 114 is formed between the insulating layer 113 and the second semiconductive layer 115, the refractory layer 114 is formed outside the conductor 111 or outside the first semiconductive layer 112 And the first semiconductive layer 112 and the insulating layer 113 are in contact with each other to be in contact with each other.

The conductor 111 and the first semiconductive layer 112 are also in contact with each other to satisfy the above conditions and the second semiconductive layer 115 and the shielding layer 116 are also in contact with each other .

As described above, the refractory cable 100 for medium or high pressure according to an embodiment of the present invention includes the conductor 111, the first semiconductive layer 112, the insulating layer 113, the refractory layer 114, The cable core 110 is formed on the basis of the entire layer 115 and the shielding layer 116. The refractory cable 100 for medium pressure or high voltage can be completed by performing the sheath and the exterior work on the outside of the cable core 110 have.

The inner sheath layer 120 may be formed on the outer side of the cable core 110. The inner sheath layer 120 may be made of polyvinyl chloride having a high impact resistance and being halogen- (PVC), polychloroprene rubber (CR), chlorosulfonated polyethylene (CSPE), chlorinated polyethylene (CPE), ethylene vinyl acetate (EVA) Lt; RTI ID = 0.0 &gt; of &lt; / RTI &gt;

The outer layer 130 is formed on the outer side of the inner sheath layer 120. The outer layer 130 may be formed of a metal material such as copper, aluminum, iron, copper alloy, aluminum alloy, Wire or the like.

The outer sheath layer 140 is formed on the outer side of the sheath layer 130. The outer sheath layer 140 has a high impact resistance and is halogen free Polyvinyl chloride (PVC), polychloroprene rubber (CR), chlorosulphonated polyethylene (CSPE), chlorinated polyethylene (CPE), ethylene vinyl acetate acetate; EVA), or a mixture of these, in the form of an extruded layer, which serves to protect the cable from external impacts and corrosion.

The structure of the inner sheath layer 120, the sheath layer 130, and the outer sheath layer 140 may vary depending on the use of the cable.

6, a single-core product made up of one cable core 110 or a multi-core product made up of two or more cores as shown in FIG. 7 Lt; / RTI &gt;

In the case of a multi-core product, a plurality of cable cores 110 are gathered at a predetermined pitch, and then the filler 150 is applied to the pores. Then, the inner sheath layer 120, the outer sheath layer 130, (140) may be formed to complete the product. The refractory cable 100 for medium pressure or high pressure shown in FIG. 7 is a three-phase cable having three cable cores 110 as an example.

The electrical characteristics and the refractory performance of the refractory cable 100 for medium or high pressure according to an embodiment of the present invention constructed as described above will be described below with reference to Table 2 in comparison with the existing configuration.

<Table 2>

The refractory layer 114 is formed between the insulating layer 113 and the second semiconductive layer 115 so that the refractory layer 114 is formed adjacent to the first semiconductive layer 112, The electrical characteristics and the fire resistance performance of each of the examples were compared with those of the present invention.

It is easy for the semi-conductive part of the refractory layer 114, that is, the part adjacent to the portion where the mica tape is wound, to be formed by winding the semi-conductive tape rather than the semi-conductive extrusion. ) Is formed by extrusion, and the second semiconductive layer 115 adjacent to the refractory layer 114, i.e., the outer semiconductive layer is formed by winding the semiconductive tape.

Conversely, in the conventional structure, the first semiconductive layer 112 adjacent to the refractory layer 114 is formed by winding a semi-conductive tape, and the second semiconductive layer 115 is formed through semi-conductive extrusion.

The semiconductive layer adjacent to the refractory layer 114 is formed by winding a semi-conductive tape around the refractory layer 114. However, the semiconductive layer adjacent to the refractory layer 114 may be formed by extrusion.

As can be seen from Table 2, the fire resistance of the refractory layer 114 for the products of 6 kV or less in comparison with the electrical characteristics and the refractory performance of the cable of the conventional construction and the refractory cable 100 for medium- (Partial discharge, withstand voltage) and fire resistance performance regardless of the position of the battery. However, when the voltage rises above 10kV, existing products are satisfactory in fire resistance but they cause electric performance degradation such as partial discharge and withstand voltage.

In addition, when the voltage is raised to 15kV or more, the existing products do not satisfy not only the electrical characteristics but also the fire resistance characteristics. On the other hand, in the case of the product of the present invention, electrical characteristics and fire resistance characteristics are satisfied for all voltage grades of 6 to 15 kV.

FIG. 8 is a cross-sectional view of a single-phase high-pressure fireproof cable according to another embodiment of the present invention, FIG. 9 is a sectional view of a three-phase high-pressure fireproof cable according to another embodiment of the present invention, In the high-voltage fireproof cable according to the second embodiment of the present invention.

Another embodiment of the present invention will be described with reference to Figs. 8 to 10. Fig.

8, the refractory cable 100 for a medium or high voltage according to the present invention further includes a second insulating layer 113b provided between the refractory layer 114 and the second semiconductive layer 115 . For convenience, the insulating layer 113 in the previous embodiment will be described as a first insulating layer 113a, which will be described separately from the second insulating layer 113b.

The refractory cable 100 for a medium or high pressure according to the previous embodiment satisfies the electrical characteristics and the refractory performance as shown in Table 2, but since the refractory layer 114 is formed in a taping shape like the mica tape 40 A gap is formed between the first insulating layer 113a and the refractory layer 114 and between the refractory layer 114 and the second semiconductive layer 115 to form air pockets 40a, There is a possibility that the dielectric breakdown may occur due to the electric field concentration by the electrode.

The second insulating layer 113b is formed by extrusion on the refractory layer 114 in order to solve the problem of degradation of electrical characteristics due to nonuniform contact between the second semiconductive layer 115 and the taped refractory layer 114 The second semiconductor layer 115 and the refractory layer 114 are not in direct contact with each other and the second insulating layer 113b having a smooth surface is in contact with the second semiconductive layer 115. [

The second insulating layer 113b may be formed through a silicon coating process and may be formed between the first insulating layer 113a and the second semiconductive layer 115 by a conventional taped refractory layer 114. [ It is possible to reduce the number of the air pockets 40a formed between the upper and lower surfaces of the refractory layer 114 and to form the refractory layer 114 in the form of a smooth layer as shown in Fig. 10 (b) The characteristics can be further improved.

In addition, a multilayer structure in which a separate refractory layer 114 and an insulating layer 113 are additionally formed outside the second insulating layer 113b may be employed to improve the refractory performance.

The electrical characteristics and the refractory performance of the refractory cable 100 for medium or high-voltage use in which the second insulation layer 113b is provided between the refractory layer 114 and the second semiconductive layer 115 are shown in Table 3, The following is a comparison with the configuration.

<Table 3>

The configuration in the case where the existing refractory layer 114 is formed adjacent to the first semiconductive layer 112, that is, outside the internal semiconducting layer, in the 6/10 kV class and the 8.7 / ) And the second semiconductive layer 115. In the case of the 18/30-kV class, the previous embodiment in which the second insulating layer 113b is not provided and the second insulating layer Layer 113b were formed on the substrate.

As compared with the 6 / 10kV class and the 8.7 / 15kV class, the conventional configuration does not satisfy both the electrical characteristics such as the partial discharge and the withstand voltage, and the fire resistance performance, but the present invention satisfies both the electrical characteristics and the fire resistance performance.

On the other hand, in the case of the previous embodiment in which the second insulating layer 113b is not formed on the refractory layer 114, as shown in Table 3, the partial discharge value at the level of 30 kV satisfies the specification of 5pC or less, In the case of the present invention in which the second insulating layer 113b is added on the layer 114, it shows a more stable electrical quality, especially 1/10 C or less for partial discharge.

Therefore, it is desirable to pay more attention to the electrical characteristics as the cable is connected to the high-voltage cable, and it is desirable to additionally form the second insulating layer 113b between the refractory layer 114 and the second semiconductive layer 115 have.

11 is a diagram showing a change in electric field intensity according to a distance from a conductor

Referring to FIGS. 6 to 11, the relationship between the electric field strength according to the distance from the conductor 111 and the optimum formation position of the refractory layer 114 will be described below. In Fig. 11, ri represents the radius between the internal (semi-conductive) and the insulation, R represents the radius between the external (semi-conductive) and the insulation, and t represents the insulation thickness.

As shown in FIG. 11, the electric field intensity is larger at a point closer to the surface of the conductor 111 in calculation of electric field intensity. Therefore, when the refractory layer 114, that is, the mica tape, is applied on the inner semiconductors having relatively high electric field strength as in the conventional refractory cable product, the phenomenon of partial discharge and dielectric breakdown due to the unevenness of the wound mica tapes is further exacerbated May occur.

On the other hand, Table 4 compares the field intensities between insulation and insulation between the inner and outer insulation through prototypes of 10kV and 15kV cables of 70SQ.

<Table 4>

As shown in Table 4, the electric field strength between the inner and outer insulation is reduced to about one half of that between the inner and outer insulation when calculating the electric field intensity at 10 and 15 kV cable. That is, when the refractory layer 114 is formed between the insulation and the insulation, the effect of reducing the influence of the electric field when the voltage is applied is reduced to 1/2 level as compared with the structure in which the refractory layer 114 is located between the inside- You can actually see that.

On the other hand, when the refractory layer 114 is applied to a region having an electric field strength of 3 kV / mm or more, the electric characteristics such as withstand voltage and partial discharge are deteriorated. Therefore, the refractory layer 114 must be applied at a distance that the electric field strength decreases and becomes lower than at least 3 kV / mm as the distance from the conductor in the radial direction of the insulating layer decreases.

On the other hand, as the distance of the refractory layer 114 from the conductor increases, the electrical quality improves. However, since the insulation thickness is increased, the outer diameter of the cable increases and the weight increases.

Therefore, it is preferable to form the refractory layer 114 in the region where the electric field intensity is at least 1 kV / mm at the electrical quality and outer-diameter optimization level. As a result, the refractory layer 114 has a field strength of 1 kV / mm to 3 kV / mm &lt; / RTI &gt; corresponds to the optimum condition.

As described above, according to the mica tape and the refractory cable according to the present invention, by applying the mica tape using the basalt fiber, productivity and reliability can be improved by simplifying the process of the refractory cable, and the cable can be made compact Or an improved refractory performance can be maintained and the mica tape can be prevented from peeling off, thereby eliminating the need for additional PE tape application.

In addition, a high adhesive force can be exhibited by using an adhesive for binding the inside of the mica layer of the mica tape and an adhesive for bonding the mica layer and the base layer with the same material.

The present invention also provides a refractory cable for a medium-voltage or high-voltage fireproof cable, which comprises a refractory layer formed between an insulating layer having a relatively low electric field strength and a second semiconductive layer, , And dielectric breakdown can be improved.

Further, when a material such as a mica tape, which is easy to be crushed by applying a refractory layer between the insulating layer having a larger radius of curvature and the second semiconductive layer, between the first semiconductive layer as the inner semiconductive layer and the insulating layer, As a result, it can be confirmed that the fire resistance performance is improved as compared with the existing products.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. You can do it. It is therefore to be understood that the modified embodiments are included in the technical scope of the present invention if they basically include elements of the claims of the present invention.

40: mica tape 41: base layer
43: Mica layer

Claims (7)

A base layer made of basalt fibers; And
And a mica layer made of a mica (MICA) laminated on the base layer. The method according to claim 1,
Wherein the adhesive used for forming the mica layer and the adhesive used for the adhesive surface of the mica layer and the base layer are the same. The method according to claim 1,
Layer structure in which at least one of the base layer and the mica layer is alternately laminated at least two times. Conductor;
An insulating layer formed outside the conductor; And
Wherein the refractory layer is made of a mica tape including a base layer made of basalt fiber. 5. The method of claim 4,
And the refractory layer is formed on the conductor. 5. The method of claim 4,
A first semiconductive layer formed adjacent to the conductor between the conductor and the insulating layer,
A second semiconductive layer formed outside the insulating layer,
And a shielding layer formed outside the second semiconductive layer,
And the refractory layer is formed between the insulating layer and the second semiconductive layer. The method according to claim 6,
And a second insulation layer provided between the refractory layer and the second semiconductive layer.

Images