JP2006139938A - Submarine cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a submarine cable capable of safely and easily finding a part likely to generate trouble in advance. <P>SOLUTION: The submarine cable has an internal conductor 3, an insulator 4 covering the internal conductor 3, and an outer layer cover 5 covering the insulator 4. A hollow tube 2 extending over a whole length of the submarine cable 1 is formed in the insulator 4, and a measuring device 6 measuring the information related to deterioration of the insulator 4 and/or the outer layer cover 5, and a state of damage is arranged in the hollow tube 2 in free movement. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a submarine cable, and more particularly to a power submarine cable that transmits electric power.

The submarine cable may be damaged by catching a ship or the like, or the outer layer coating of the cable may be damaged.
When the outer layer coating of the submarine cable is damaged, salt, moisture, etc. permeate the outer layer coating and / or the insulator, causing the dielectric to break down.
If the insulation breaks down, it may lead to a problem that a short circuit accident occurs between the inner conductors of each cable.
In general, the life of a submarine cable is considered to be about 30 years. However, due to the problems of deterioration and damage of the outer layer coating, the submarine cable is inspected once every six years. The inspection once every six years is generally performed by a diving worker, and the appearance is generally visually checked by the diving worker.

By the way, even if such a submarine worker inspects the appearance of the submarine cable, there are actually places where the submarine cable has been buried in the seabed or parts that have been submerged in the seabed that cannot be submerged. There are many places that cannot be done. Therefore, there has been a problem that inspection over the entire length of the submarine cable is practically impossible.
In addition, the appearance inspection of submarine cables by diving workers has the problems of being accompanied by the danger of diving, and the considerable time and cost.
On the other hand, in Patent Document 1 below, when an accident such as a short circuit occurs in a submarine cable, an impact voltage is applied to the submarine cable to cause a discharge at the accident point, and a sound wave resulting from the discharge is captured by an underwater microphone. It describes the detection of accident points.
JP 2000-234952 A

However, the above-mentioned Patent Document 1 has a problem that an accident point cannot be detected until an accident has actually occurred in the submarine cable, and a location where an accident is likely to occur cannot be found.
As a means for preventing accidents, there is a measurement method called “DC leakage current measurement”. In this DC leakage current measurement, a high DC voltage is applied between a conductor and a shielding layer, and a change in leakage current with time is measured to determine deterioration. However, DC leakage current measurement has the following problems.
・ Measurement is not possible unless the power transmission of the submarine cable is stopped at the time of inspection.
In order to accurately measure the deterioration state, it is better to increase the measurement voltage, but in order not to deteriorate the insulator by applying a direct current, it is better to make it as low as possible, and it is difficult to balance it.
-Measurement errors occur due to the influence of creeping leakage current at the cable end, making it difficult to judge cable deterioration.
The present invention has been developed to solve the above-described problems. That is, an object of the present invention is to provide a submarine cable capable of finding a place where an accident of a submarine cable is likely to occur in advance, accurately, safely and easily, and without stopping power transmission.

In order to achieve the above object, the submarine cable according to claim 1 is a submarine cable (1) laid on the seabed, and includes an inner conductor (3a) and an insulator (4) covering the inner conductor (3a). ) And an outer layer coating (5) covering the insulator (4), and inside the insulator (4), a hollow tube (2) extending the entire length of the submarine cable (1) is provided. In 2), a measuring device (6) for measuring information on the deterioration and damage state of the insulator (4) and / or outer layer coating (5) is movably arranged.
The submarine cable according to claim 2, wherein a pressure regulator (20) is provided at least at one end of the hollow pipe (2), and a measuring device is provided by a differential pressure before and after the measuring device (6) in the hollow pipe (2). (6) is moved, It is characterized by the above-mentioned.
The submarine cable according to claim 3 is a reinforcing means (30) having a coil shape or a ring shape for preventing the hollow tube (2) from being crushed on the outer peripheral surface and / or the inner peripheral surface of the hollow tube (2). ) Is provided.
The submarine cable according to claim 4 is characterized in that a liquid (40) is sealed in the hollow pipe (2).

  According to the submarine cable of the present invention of claim 1, the temperature of the submarine cable can be measured without stopping power transmission by measuring the temperature, eddy current, etc. using a measuring device, for example, a temperature sensor or an eddy current flaw detector. It is possible to judge deterioration, damage, etc. of insulators and coatings, and to perform inspection over the entire length of the submarine cable. In addition, this makes it possible to perform inspections safely and at low cost since the diving operation that has been conventionally performed is not required.

  According to the submarine cable of the present invention of the second aspect, the measuring device in the hollow pipe can be moved with a simple structure.

  According to the submarine cable of the present invention of claim 3, the hollow tube is not crushed by the reinforcing means having a coil shape or a ring shape even when the whole becomes a high pressure. Therefore, the submarine cable is laid on, for example, the deep sea bottom. be able to. Such a deep sea is a place where it has been impossible to check due to inability to dive, and it is possible to check the submarine cable even in such a place.

  According to the submarine cable of the present invention of claim 4, since the hollow pipe is not crushed by the liquid in the hollow pipe even when the entire pressure becomes high, the submarine cable can be laid on the deep sea, for example. Such a deep sea is a place where it has been impossible to check due to inability to dive, and it is possible to check the submarine cable even in such a place.

  A submarine cable is provided with a hollow pipe in the submarine cable for the purpose of detecting damage and deterioration of the insulator and / or outer layer coating and grasping it by inspection to prevent short circuit accidents. This was realized by arranging a measuring device for measuring information on deterioration and damage state of the body and / or outer layer coating.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 4 show Example 1 of the submarine cable of the present invention, FIG. 1 is an enlarged longitudinal sectional view, FIG. 2 is a perspective view schematically showing, and FIG. 3 is a conceptual diagram showing a measuring device. 4 is a conceptual diagram showing the arrangement of various sensors in the measuring apparatus. The first embodiment is applied to a power submarine cable for power transmission.

  As shown in FIG. 1, the power submarine cable 1 according to the first embodiment includes a hollow tube 2 disposed at the center of the cable and three powers disposed at equal intervals in the circumferential direction so as to surround the hollow tube 2. The cable 3 includes an insulator 4 provided so as to surround the hollow tube 2 and the power cable 3, and an outer layer coating 5 that covers the insulator 4.

The hollow tube 2 has a tube shape and is formed of, for example, a low friction resin such as polyolefin resin. The internal space of the hollow tube 2 is a moving space for moving the measuring device as will be described later.
The three power cables 3 are known power cables 3, and an insulator 3b is provided so as to surround the inner conductor 3a, and an exterior body 3c that covers the insulator 3b is further provided.
As the insulator 4, an insulator such as a butyl rubber mixture, an ethylene propylene rubber mixture, or a polyethylene mixture is used.
As the outer layer coating 5, a single iron wire using a galvanized iron wire is used (not shown), and a polypropylene yarn is applied as a seat on it.
Such a power submarine cable 1 has an outer diameter of about 300 mm, and the hollow tube 2 has an inner diameter of about 75 mm.

As shown in FIG. 2, a measuring device 6 is movably disposed in such a hollow tube 2. The measuring device 6 (sensor, measuring means, etc.) measures information relating to the deterioration and damage state of the insulator 4 and / or the outer layer coating 5.
As shown in FIG. 3, the measuring device 6 includes a temperature sensor 7 that detects a temperature, a magnetic sensor 8 that detects a magnetic field, a gyro sensor 9 that detects a position, and an infrared ray that detects an obstacle in the cavity tube 2. The sensor 10, the microprocessor 11 that calculates and processes information from the sensors 7, 8, 9, and 10, and the processing such as the calculation and processing performed by the microprocessor 11 are stored as programs and various types of processing performed by the microprocessor 11 It has a memory 12 that records data (temperature, magnetism, position, etc.) together with time information, and a transmitter 13 that transmits data processed by the microprocessor 11.

The temperature sensor 7 detects the temperature as information on the deterioration and damage state of the insulator 4 and / or the outer layer coating 5. That is, when the insulator 4, the outer layer coating 5 and the like deteriorate and damage proceeds, seawater salt and moisture penetrate into the insulator 4, the outer layer coating 5, and do not cause a short circuit of the internal conductor 3a. Leakage current is generated and heat is generated between the adjacent inner conductors 3a.
Therefore, if the temperature sensor 7 is movably disposed in the hollow tube 2, the temperature inside the power submarine cable 1 can be detected while moving in the length direction.
And if the location which generate | occur | produced is detected with the temperature sensor 7, it can be judged that the detected location may have deteriorated or damaged the insulator 4 and / or the outer layer coating 5. In addition, when the temperature is abnormally higher than other parts, it is judged that the degree of deterioration and / or damage is severe and the power submarine cable 1 must be repaired or replaced urgently. Can do.
As shown in FIGS. 3 and 4, four such temperature sensors 7 are arranged at equal intervals in the circumferential direction.

The magnetic sensor 8 detects magnetism as information on the deterioration and damage state of the insulator 4 and / or the outer layer coating 5. That is, a change in eddy current generated by an eddy current flaw detector using the magnetic sensor 8 is detected. The material of the insulator 4 and the outer layer coating 5 of the power submarine cable 1 is uniformly formed. However, if there is a scratch or the like, the portion is a non-qualitative portion. Then, as the eddy current flaw detector moves, if it reaches a non-qualitative portion (such as a flaw), the eddy current generated in the insulator 4 and / or the outer layer coating 5 changes.
Therefore, when the eddy current flaw detector is movably arranged in the cavity tube 2, the insulator 4 and / or the orbital insulator 1 and / or the outer layer coating 5 is detected by moving while detecting the damage of the insulator 4 and / or the outer coating 5 of the power submarine cable 1. It can be determined that the outer layer coating 5 may be deteriorated or damaged.
As shown in FIGS. 3 and 4, four such magnetic sensors 8 are arranged at equal intervals in the circumferential direction alternately with the temperature sensor 7.

The gyro sensor 9 performs position sensing by calculating a moving distance by transmitting / receiving radio waves and comparing with previous data. Then, the position of the measuring device 6 can be specified by position sensing by the gyro sensor 9, and the position where the abnormality of the insulator 4 and / or the outer layer coating 5 is detected by the temperature sensor 7 and / or the magnetic line sensor 8 is specified. The
One such gyro sensor 9 is arranged in the measuring apparatus 1.

The infrared sensor 10 detects abnormalities in the shape of the hollow tube 2 and foreign matters. That is, infrared rays are emitted from the infrared sensor 10 and the reflected waves are received to detect the shape abnormality of the hollow tube 2 and the foreign matter in the hollow tube 2 to confirm whether a space for movement is secured. can do. The infrared sensor 10 detects the obstacle that hinders the movement of the hollow tube 2 as the moving space of the measuring device 6, and provides information on the deterioration and damage state of the insulator 4 and / or the outer layer coating 5. Since it is not a detection, it is not an essential configuration. Further, the gyro sensor 9 and the infrared sensor 10 can be shared, and by sharing these, the measurement device 6 can be reduced in weight and power consumption can be reduced.
Such infrared sensors 10 are arranged one by one before and after in the measuring apparatus 1.

  The microprocessor 11 first reads a program stored in the memory 12, and then receives information from the temperature sensor 7, the magnetic sensor 8, the gyro sensor 9, and the infrared sensor 10 according to instructions of the program, and calculates the information according to the program. The processed data is transmitted to the memory 12 after being processed.

The transmitter 13 transmits various data processed by the microprocessor 11 to a receiver (not shown) using the hollow tube 2 as a waveguide. Such transmitters 13 are arranged one by one before and after in the measuring apparatus 1.
Various data transmitted by the transmitter 13 includes time information and position information together with data detected by the temperature sensor 7 and the magnetic sensor 8. In order to transmit various data by the transmitter 13, it may be transmitted sequentially in real time, or may be transmitted as a packet after collecting a predetermined amount of data. When transmitting sequentially in real time, various data are not stored in the memory 12 but directly transmitted from the transmitter 11 from the microprocessor 11. When transmitting various data as packets, the data is temporarily stored in the memory 12 and then transmitted when the data is collected in a predetermined capacity. In addition, if the data in the memory 12 is taken out after moving the measuring device 6 to the land, the transmitter 13 becomes unnecessary.

  Thus, the various data acquired by the measuring device 6 is sent from the transmitter 13 to the receiver on land or taken out from the memory 11 of the measuring device 6 moved to the land, and analyzed, whereby the insulator 4 And / or the location where the outer layer coating 5 is deteriorated or damaged is determined.

As described above, since the hollow tube 2 is provided inside the power submarine cable 1 and the measuring device 6 is movably disposed in the hollow tube 2, it is possible to easily detect deterioration or damage of the insulator 4 and / or the outer sheath 5. Thus, it is possible to prevent an accident such as a short circuit between the inner conductors 3a inside the power submarine cable 1.
In order to allow the measuring device 6 to self-run in the hollow tube 2, for example, it is conceivable to mount the measuring device 6 on a known self-running means (robot).

FIG. 5 is a side view schematically showing the submarine cable of the present invention in the second embodiment. In the power submarine cable 1A according to the second embodiment, a blower device 20 'as a pressure regulator 20 is provided at one end of the hollow tube 2 in order to easily move the measuring device.
That is, the blower 20 'is connected to one end of the hollow tube 2 of the power submarine cable 1A, and the other end of the hollow tube 2 is open.
The measuring device 6 is formed to be slightly smaller in cross-sectional shape substantially the same as that of the hollow tube 2.
Thus, when the air blower 20 'is driven, the pressure between the air blower 20' and the measuring device 6 is increased in the hollow tube 2, and the measuring device 6 can be pushed and moved to the other, which is relatively simple. With the structure, the moving means of the measuring device 6 can be realized.

FIG. 6 shows a modification of the power submarine cable 1A according to the second embodiment. The power submarine cable 1A ′ according to this modification is such that a blower device 20 ′ is connected to both ends of the cavity tube 2, respectively.
In the case of this modification, the measurement device 6 can be moved back and forth by switching the driving of the two blower devices 20 ′. For example, when there is a place where measurement is desired again, the measurement device 6 can be easily operated. Can be reversed.
In the second embodiment, the air blower 20 ′ is used as the pressure regulator 20. However, the present invention is not limited to this, and may be a high pressure generator or a negative pressure generator. Also good. Further, a pressure regulator capable of generating a high pressure and a negative pressure may be provided at one end and / or both ends of the hollow tube 2.

7 is a side view schematically showing the submarine cable of the present invention in Example 3. FIG. The power submarine cable 1B according to the third embodiment is provided with reinforcing means 30 so that the hollow tube 2B is not crushed.
That is, a coil 30 'as a reinforcing means 30 is wound around the hollow tube 2B of the power submarine cable 1B so as to be in close contact with the outer peripheral surface thereof.
The coil 30 'may be made of metal or may be made of hard synthetic resin. In the third embodiment, the coil 30 'is provided on the outer peripheral surface of the hollow tube 2B. However, the present invention is not limited to this, and may be provided on the inner peripheral surface of the hollow tube 2B. Further, the coil 30 'may be provided on both the inner peripheral surface and the coil 30'.

Therefore, according to the power submarine cable 1B, even if a high voltage is applied to this, the hollow tube 2B is not crushed. Therefore, a moving space for the measuring device 6 can be secured, so It is also possible.

FIG. 8 shows a modification of the power submarine cable 1B of the third embodiment. The power submarine cable 1B according to this modification is provided with a plurality of rings 31 at appropriate intervals on the outer peripheral surface of the hollow tube 2B ′. It is. FIG. 8 is a schematic perspective view showing the hollow tube 2B ′ and a plurality of rings 31 provided thereon.
Even in such a modification, the power submarine cable 1B can be submerged in the seabed such as the deep sea, can withstand the high pressure, and the hollow tube 2B 'is not crushed. Can be secured.

9 is a side view schematically showing the submarine cable of the present invention in Example 4. FIG. The power submarine cable 1C according to the fourth embodiment is another example in which the hollow tube 2C is hardly crushed.
That is, the power submarine cable 1C is obtained by enclosing a liquid 40 such as oil inside the hollow tube 2C.
As a result, as in the third embodiment, the power submarine cable 1C is submerged in the seabed such as the deep sea, and even if a high pressure is applied, the hollow tube 2C is not crushed. Can do.

FIG. 10 is a cross-sectional view of the submarine cable of the present invention according to Example 5. The power submarine cable 1D according to the fifth embodiment is arranged so that the three power cables 3 are in contact with each other, and the three hollow tubes 2D are arranged in an outer gap between the adjacent power cables 3, The cross-sectional shape of the hollow tube 2D is substantially fan-shaped. And the measuring device 6 is arrange | positioned separately for each cavity pipe | tube 2D.
Thereby, according to the electric power submarine cable 1D concerning this Example 5, an outer diameter can be made smaller than the electric power submarine cables 1, 1A, 1B, 1C concerning the said Examples 1 thru | or 4. For example, when the power cable 3 having the same diameter as the power submarine cables 1, 1 </ b> A, 1 </ b> B, and 1 </ b> C according to Examples 1 to 4 is used, the power submarine cable 1 </ b> D according to Example 5 has an outer diameter of It can be about 200mm. Since the submarine cable is affected by tidal currents, it is extremely effective to be able to form the hollow pipe 2D with a small diameter.

  Further, according to the power submarine cable 1D according to the fifth embodiment, the hollow tube 2D that allows the measuring device 6 to move is arranged at a position close to the outer layer covering 5 side rather than the center of the power submarine cable 1D. It can be detected at the initial stage of deterioration or damage of the covering 5 (a state in which the degree of deterioration is small), and the abnormality of the power submarine cable 1D can be reliably detected before a short circuit accident occurs.

  In each of the above-described embodiments, the case where one measuring device 6 is arranged in the hollow tube 2 has been described. However, the present invention is not limited to this, and a plurality of measuring devices 6 may be provided. In the case where a plurality of measuring devices 6 are arranged in the hollow tube 2, it is conceivable that each measuring device 6 is connected in a daisy chain with signal lines or the like. Thus, when the measuring device 6 is connected in a daisy chain shape, the inside of the hollow tube 2 can be easily moved by pulling one end thereof.

  The present invention is not limited to the embodiment of the invention described above, and can be applied to various cables submerged in the seabed, such as a communication submarine cable or a submarine cable combining these, and does not depart from the gist of the present invention. Can be applied.

It is an expanded sectional view of the electric power submarine cable in Example 1. FIG. 2 is a perspective view schematically showing a main part in Example 1 with a cut-out. 1 is a perspective view schematically showing a measuring device in Example 1. FIG. It is a front view which shows roughly arrangement | positioning of the various sensors in the measuring device in Example 1. FIG. It is a schematic side view which cuts off the whole electric power submarine cable in Example 2, and is shown. It is a schematic side view which cuts out the whole electric power submarine cable in the modification of Example 2, and is shown partially. It is a perspective view which cuts and shows the principal part in Example 3. FIG. FIG. 10 is a perspective view showing only a hollow tube in a modified example of Example 3. It is a perspective view which cuts and shows the principal part in Example 4. FIG. It is an expanded sectional view of the electric power submarine cable in Example 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power submarine cable 2 Cavity pipe 3 Power cable 3a Inner conductor 3b Insulator 3c Outer body 4 Insulator 5 Outer layer coating 6 Measuring device 7 Temperature sensor 8 Magnetic sensor 9 Gyro sensor 10 Infrared sensor 11 Microprocessor 12 Memory 13 Transmitter 1A Power Submarine cable 20 Pressure regulator 20 'Blower 1A' Power submarine cable 1B Power submarine cable 2B Cavity tube 30 Reinforcing means 30 'Coil 2B' Cavity tube 31 Ring 1C Power submarine cable 2C Cavity tube 40 Liquid 1D Power submarine cable 2D Cavity tube

Claims (4)

A submarine cable (1) laid on the seabed,
An inner conductor (3a), an insulator (4) covering the inner conductor (3a), and an outer layer coating (5) covering the insulator (4),
Inside the insulator (4) is provided a hollow tube (2) extending the full length of the submarine cable (1),
In the hollow pipe (2), a measuring device (6) for measuring information on the deterioration and damage state of the insulator (4) and / or outer layer coating (5) is movably disposed. Submarine cable. A pressure regulator (20) is provided at least at one end of the hollow tube (2), and the measuring device (6) is moved by a differential pressure before and after the measuring device (6) in the hollow tube (2);
The submarine cable according to claim 1. Coiled or ring-shaped reinforcing means (30) is provided on the outer peripheral surface and / or inner peripheral surface of the hollow tube (2) to prevent the hollow tube (2) from being crushed.
The submarine cable according to claim 1, wherein the submarine cable is provided. The liquid (40) was sealed in the hollow tube (2),
The submarine cable according to any one of claims 1 to 3, wherein the submarine cable is provided.

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