JP2015149145A - power distribution cable and signal system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power distribution cable which is installed along an orbit for feeding electric power to a traffic apparatus or the like and which can secure conduction even if it is burnt by a wayside fire without requiring time and cost.SOLUTION: There is provided a power distribution cable 100 comprising: a conductor 1; an insulation layer 3 applied to the outside of the conductor 1; and a shield layer 2 applied to the outside of the insulation layer 3. Further, a fire-resistant layer 2 having a thickness of above 2.2 mm is applied to a space between the conductor 1 and the insulation layer 3. Thus, the fire resistant layer 2 is not subjected to insulation breakdown even after it is burnt by a wayside fire, so that a short-circuit between the conductor 1 and the shield layer 4 is not caused.

Description

  The present invention relates to a power distribution cable for supplying power to equipment for operating a train, and a signal system using the power distribution cable.

  Each train on the track is traveling in the upward direction, traveling in the downward direction, traveling at a high speed, traveling slowly, or stopping at the station. doing. However, each place on the track is equipped with equipment (hereinafter, traffic lights, etc.) that gives instructions on traveling speed and whether or not to enter a predetermined section, such as traffic lights, and each train travels according to instructions from traffic lights, etc. Each train can travel smoothly on the same track without colliding. On the other hand, in the state where the traffic light etc. does not function, the train operation becomes extremely difficult.

  By the way, electric power is required to make a traffic light or the like function. For this reason, a power distribution cable is disposed along the track on the track, and a traffic light or the like is supplied with power from the power distribution cable (see Patent Document 1). The distribution cable mainly includes a conductor, an insulating layer provided outside the conductor, a shielding layer provided outside the insulating layer, and a sheath provided outside the shielding layer, and a 6.6 kV cross-linked polyethylene insulated vinyl sheath cable. (Hereinafter, 6.6 kVCV cable) is used.

JP 2006-320139 A

  By the way, in urban areas, buildings are often provided up to the vicinity of tracks and power distribution cables. However, since the 6.6kVCV cable does not have fire resistance, when a fire breaks out from these buildings (so-called fire along the line), the insulation layer of the power distribution cable is burned and the conductor and the shielding layer are short-circuited. There is a risk that power cannot be supplied to

  In order to cope with this problem, the inventor (1) wraps a fireproof sheet around the installed distribution cable, (2) changes the arrangement route of the installed distribution cable, (3) 6. Three methods of using a fireproof layer provided in advance on the outside of the 6 kVCV cable were examined. As a result, as for (1), since it is a work at a high place, there are problems such as troublesome work during winding and maintenance after winding, long-term use, high cost, and loss of the beauty of the railway. found. As for (2), it was found that it was difficult to secure a new site on a railway line in an urban area where a fire along the line was expected, and that it was necessary to attach a trough and the cost was high. Regarding (3), the problem was that the manufacturing cost was high because the fireproof layer was outside the cable sheath and the amount of fireproof layer used was increased.

Next, the inventor has paid attention to an indoor fireproof cable that has not been used as a distribution cable for outdoor use (including railway use). The indoor fireproof cable is equipped with a fireproof layer between the conductor and the insulation layer, so that even if a fire occurs and the insulation layer burns out, the insulation resistance and dielectric strength between the conductor and the shielding layer are maintained, The power supply to evacuation facilities and fire extinguishing facilities can be secured. This indoor fireproof cable was subjected to a combustion test (IEC60332-21; combustion temperature 750 ° C., combustion time 90 minutes, fire-extinguishing 20 hours after fire extinguishing), fire-extinguished with water, and then turned on again. The refractory layer applied to the outside was broken down, and the conductor and the shielding layer outside the refractory layer were short-circuited. The result is that the indoor fireproof cable is designed so that it can be energized even during the occurrence of a fire (assuming approximately 30 minutes). It is because it is not done.
As described above, conventionally, there is no way to prevent the power distribution cable from being turned off due to a fire along the line, in addition to high cost and great effort.

  The present invention has been made in view of the above problems, and in a power distribution cable that is arranged along a track and supplies power to a traffic light or the like, it is energized even after it is burned out by a fire along the line, without incurring labor and costs. The purpose is to ensure it.

  The inventor came up with the idea of devising the thickness of the refractory layer covering the conductor of the indoor refractory cable as a result of repeated trial and error to provide the indoor refractory cable with the performance required for the distribution cable. . FIG. 4 is a graph showing the relationship between the thickness of the refractory layer and the minimum insulation resistance after the combustion test specified in IEC 60332-21, obtained during the development process. As shown in FIG. 4, when the thickness of the refractory layer is 2.2 mm or less, the minimum insulation resistance is too low (less than 2 MΩ), and the level is shorted. When the thickness was increased to 2.5 mm, it was suddenly possible to maintain an insulation resistance (11 MΩ or more) sufficient not to cause a short circuit even after combustion. Further, when the thickness was further increased to 2.9 mm, the insulation resistance further increased. From these results, the inventors have obtained the knowledge that the current-carrying performance can be maintained even after burning by setting the thickness of the refractory layer to a predetermined value or more, and the present invention has been achieved.

  The present invention is a distribution cable comprising a conductor, an insulating layer applied to the outside of the conductor, and a shielding layer applied to the outside of the insulating layer, wherein the thickness is between the conductor and the insulating layer. A refractory layer exceeding 2.2 mm is provided.

In this way, even if energization is resumed after the occurrence of a fire along the line, the refractory layer will not break down and the conductor and shielding layer will not be short-circuited. Become. For this reason, in a place where a plurality of distribution cables are arranged only on one side of the track, if at least one of the distribution cables is a distribution cable according to the present invention, a line-side fire occurs in the place, Even after the power distribution cable is burned out, power distribution is ensured by the power distribution cable according to the present invention, so that the operation of the train can be resumed promptly.
In addition, since energization can be continued for at least 20 hours after the fire along the railway line is extinguished, the train must be operated with the burned distribution cable during the business hours of the day, and replacement must be performed after the business hours are over. Can do. Therefore, recovery can be performed without interrupting the train operation.

Desirably, in the above-described invention, the fireproof layer is formed by laminating 14 or more layers of mica tape having a thickness of 0.18 mm.
If it does in this way, a fireproof layer can be easily formed only by winding a commercially available mica tape around a conductor.

In addition, the present invention provides a signal system comprising: a power distribution cable disposed along a track laying direction; and a signal device provided on a side of the track and connected to the power distribution cable to receive power. Then, the power distribution cable described above is used as the power distribution cable.
If it does in this way, even after a wiring cable burns out by a fire along a line, since a distribution cable ensures energization, operation of a train can be restarted promptly.

  According to the present invention, in a distribution cable that is arranged along a track and supplies electric power to a traffic light or the like, it is possible to ensure energization even after being burned out due to a fire along the line, without taking time and cost.

It is the perspective view which showed the front-end | tip part of the power distribution cable which concerns on embodiment of this invention. It is a table | surface which shows the result of having done the fire resistance test of the power distribution cable of FIG. 1, (a) is a result when the mica tape of a fireproof layer is made into 7 sheets (14 layers), (b) is 8 sheets (16 It is a result in the case of layer). It is the figure which showed the example of arrangement | positioning of the power distribution cable in an urban area. It is the graph which showed the relationship between the thickness of a fireproof layer, and the minimum insulation resistance after the combustion test prescribed | regulated by IEC60332-21.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of distribution cable]
First, a specific configuration of the power distribution cable according to the embodiment of the present invention will be described.
As shown in FIG. 1, the power distribution cable 100 is a bundle of three high-pressure fireproof cables 10a, 10b, 10c. The configurations of the high-pressure fireproof cables 10a, 10b, and 10c are the same except that they are color-coded for identification (for example, red, blue, and yellow).
Each high voltage fireproof cable 10a, 10b, 10c includes a central conductor 1, a fireproof layer 2 covering the conductor 1, an insulating layer 3 applied to the outside of the fireproof layer 2, a semiconductive tape 4 applied to the outside of the insulating layer 3, A shielding layer 5 applied to the outside of the conductive tape 4, a pressing tape 6 that fixes the shielding layer 5 from the outside, a sheath 7 that covers the pressing tape 6 from the outside and forms the surface layer portion of the high-pressure fireproof cables 10a, 10b, and 10c. It is configured.

The conductor 1 is a stranded wire of an annealed copper strand.
The insulating layer 3 is made of cross-linked polyethylene.
The shielding layer 5 is formed of an annealed copper tape.
The sheath 7 is made of flame resistant polyethylene.

  The refractory layer 2 of the present embodiment has a glass mica tape 21 (thickened with mica laminated on a glass cloth) 21 having a thickness of 0.18 mm in a spiral shape and the tip in the axial direction of the portion wound around the conductor 1 Wrap so that the half on the side and the half on the axial base end side of the part to be wound overlap, and wind the other glass mica tape 21 from the outside in the same way. Alternatively, eight glass mica tapes 21 are wound. By adopting such a winding method, since one glass mica tape 21 is doubled, the cross section of the refractory layer 2 when the high-pressure refractory cables 10a, 10b, 10c are cut along a plane orthogonal to the axial direction is as follows. The 14-layer or 16-layer glass mica tape 21 is laminated. The calculated thickness of the refractory layer 2 configured as described above is 2.52 mm or 2.88 mm, but an error may occur during manufacture, and in the case of 14 layers, 2.0-2. There is a width of 5 mm. On the other hand, in the case of the conventional 12 layers, it is 1.8-2.2 mm. From this, the thickness of the refractory layer 2 of the present embodiment is over 2.2 mm, which is possible only when seven or more glass mica tapes having a thickness of 0.18 mm are wound.

[Fireproof performance of power distribution cable]
Next, the fire resistance performance of the power distribution cable 100 will be described.
In the description, the fire resistance test for comparing the fire resistance of the power distribution cable 100 of the present embodiment (7 (14 layers) and 8 (16 layers) of mica tape) with an indoor fire cable. Went. As the indoor fireproof cable, six mica tapes (12 layers) of the fireproof layer were used, and other configurations were the same as those of the power distribution cable 100 of the present embodiment.

As a specific procedure of the fire resistance test, first, a 1.3 m long sample is cut from the 7-winding distribution cable 100 of mica tape and supported by a testing device using a lashing wire and a messenger wire, and the sample is actually Made it the same as the usage status of the power distribution cable. And while applying the voltage of 4 kV which is the ground voltage of the maximum use voltage (6.9 kV) of a 6.6 kV electric wire to both ends of a sample, the combustion temperature (750 degreeC) based on IEC60332-21, combustion time (90 Minutes), the middle part of the sample was burned. Then, the voltage application of 4 kV was interrupted once, and the insulation resistance between the conductor and the shielding layer was measured by applying a voltage of 500 V between the conductor and the shielding layer.
Thereafter, the voltage application to the sample was temporarily stopped, and 16 L of water was continuously applied for about 10 minutes while moving the sample from one end to the other end in the middle of the sample using a watering can to extinguish the sample.
Then, the same voltage as that during combustion was again applied to the sample for 20 hours, and the insulation resistance was measured.

  Thereafter, samples were cut out from the 8-winding distribution cable 100 of mica tape and the indoor fireproof cable of 6 sheets, respectively, and the same fire resistance test as the above-described sample of the distribution cable 100 of 7-winding mica tape was performed.

  As a result, in a fire resistance test using an indoor fire resistant cable as a sample, immediately after resuming energization after the fire was extinguished, the test apparatus detected an overcurrent and interrupted the current. This indicates that the refractory layer breaks down and the conductor and the shielding layer are short-circuited.

On the other hand, in the fire resistance test using the distribution cable 100 of the present embodiment with seven rolls of mica tape as a sample, as shown in FIG. 2A, three fire resistant cables 10 (red phase, blue phase, yellow phase). ) In all cases, although the insulation resistance decreased during combustion, the fire resistance layer 2 remained after the fire was extinguished, and the insulation resistance recovered to the same level as before the test. Even after 20 hours, the conductor 1 and the shielding layer 4 There was no short circuit.
This means that if a fire along the line that causes the power distribution cable 100 to burn out occurs, the train operation can be resumed immediately after the fire is extinguished, as long as there is no serious damage to other equipment. It can be continued. Since the length of 20 hours exceeds the length of the business hours of the day, the burned distribution cable 100 can be used until the final train passes, and replacement with a new cable is performed during maintenance work at night. be able to.
Also, in the fire resistance test using the power distribution cable 100 of the present embodiment with 8 sheets of mica tape as a sample, the same result as in the case of 7 sheets was obtained as shown in FIG.

[Use example of power distribution cable]
Next, a usage example of the power distribution cable 100 will be described.
Since the distribution cable 100 of the present embodiment has the fire resistance as described above, it is possible to ensure energization for about 20 hours even if the power distribution cable 100 burns out due to a fire along the line. Conventionally, without stopping, as shown in FIG. 3, at least one of the distribution cables 110 used mainly and the distribution cable 110 used as a spare is arranged on one side of the track R (for example, on the upper side). If the distribution cable 100 of this embodiment is used as the distribution cable 100 of this embodiment, even if both of the distribution cables are burned out due to a fire along the line, the distribution cable 100 of this embodiment ensures energization. Train operation can be resumed promptly.

  In addition, in order to prevent both of the two distribution cables from being burnt, conventionally, at least at the place where one distribution cable is disposed on one side of the track and the other distribution cable is disposed on the other side of the track. By using one power distribution cable as the power distribution cable 100 according to the present embodiment, the two power distribution cables can be collectively disposed on one side. If it does so, since maintenance of both the power distribution cables can be performed at once, the maintenance work can be facilitated.

  As described above, the power distribution cable 100 of this embodiment includes the conductor 1, the insulating layer 3 applied to the outside of the conductor 1, and the shielding layer 4 applied to the outside of the insulating layer 3, 1 and an insulating layer 3 are provided with a refractory layer 2 having a thickness of more than 2.2 mm.

By doing so, even if the energization is resumed after the occurrence of a fire along the line, the refractory layer 2 does not break down and the conductor 1 and the shielding layer 4 are not short-circuited. It becomes possible. For this reason, if at least one of the distribution cables is used as the distribution cable 100 according to the present invention in a place where a plurality of distribution cables are arranged only on one side of the track, a fire along the line occurs in the place. Even after the power distribution cable is burned out, the power distribution is ensured by the power distribution cable 100 according to the present embodiment, so that the operation of the train can be resumed promptly.
In addition, since the energization can be continued for at least 20 hours after the fire along the line is extinguished, the train is operated with the burned distribution cable 100 during the business hours of the day, and the replacement work is performed after the business hours are over. be able to. Therefore, recovery can be performed without interrupting the train operation.

In addition, the fireproof layer 2 of the power distribution cable 100 of the present embodiment is formed by laminating 14 or more layers of mica tape 21 having a thickness of 0.18 mm.
By doing so, the fireproof layer 2 can be easily formed simply by winding a commercially available mica tape around the conductor 1.

As mentioned above, although this invention was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.
For example, in the above embodiment, seven or eight glass mica tapes are used due to cost and the like. However, in order to further improve the fire resistance regardless of the cost, nine or more glass mica tapes are wound. May be.
Moreover, in the said embodiment, although the one glass mica tape was wound so that it might become double, two thirds of the axial direction front end side of the wound part and the axial direction base end side of the part to wind from now on One glass mica tape may be wound in triplicate by winding so that two-thirds overlap.
Moreover, in the said embodiment, although what bundled three high voltage | pressure fireproof cables was used as the power distribution cable, it is good also as what bundled 1, 2, or 4 or more.
Moreover, in the said embodiment, although the conductor was made from the circular compression strand of an annealed copper strand, what was formed with other metals, such as aluminum, what was compressed to other cross-sectional shapes, what was not compressed, Alternatively, it may be a single wire.
Further, in the above embodiment, it has been described that it is useful when both the No. 1 line and No. 2 line are arranged on one side of the track, but the No. 1 line is on one side of the track and the No. 2 line is on the other side of the track. Even if it is a case where it is arrange | positioned, it is good also as a power distribution cable of the said embodiment which is highly likely to burn out at the time of fire both of No. 1 and No. 2.

100 Distribution Cable 10 High Pressure Fireproof Cable 1 Conductor 2 Fireproof Layer 21 Glass Mica Tape 5 Shielding Layer

Claims (3)

A power distribution cable comprising a conductor, an insulating layer applied to the outside of the conductor, and a shielding layer applied to the outside of the insulating layer,
A power distribution cable, wherein a fire-resistant layer having a thickness of more than 2.2 mm is provided between the conductor and the insulating layer.   The power distribution cable according to claim 1, wherein the fireproof layer is a laminate of 14 or more layers of mica tape having a thickness of 0.18 mm. A signal system comprising: a power distribution cable disposed along a track laying direction; and a signal device provided on a side of the track and connected to the power distribution cable to receive power supply,
A signal system using the power distribution cable according to claim 1 or 2 as the power distribution cable.

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