Cable movement observation method and observation device in sand-filled hand hole or the like

Abstract

To provide a cable movement observation method having an extremely simple constitution and being capable of reliably performing observation.SOLUTION: An opening 6 is provided on a ceiling plate 2a of a hand hole 2, a cylindrical housing 7 covering the opening 6 and having a height to a ground surface is provided on a top face of the ceiling plate 2a, and an upper opening of the cylindrical housing 7 is covered by an opening / closing lid 8. A guide tube 11 with an upper end fixed to an inner periphery of the cylindrical housing 7 is provided, a lower part of the guide tube 11 is pulled through the opening 6 into the hand hole 2, a bent part 11a is provided by bending a pulled-in end at an upper side of a cable 1 inside of the hand hole 2, and one end of a wire 14 with the other end fixed to an outer periphery of the cable 1 is inserted into the guide tube 11 and suspended from an upper end 11b of the guide tube 11 to an external lower side of the guide tube 11. The wire 11 in a location protruding from the upper end of the guide tube 11 is marked and left for a fixed period of time and thereafter, the opening / closing lid 8 is opened, thereby measuring a pulling-in degree of the cable 1 according to a position of the marked location of the wire 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention relates to a method for observing cable movement due to sliding caused by the difference in height at which the cable is laid and the wave-riding phenomenon in handholes, manholes, U-shaped troughs, etc. of underground power transmission lines, etc., where the insides are filled with sand or filled with groundwater, and to an observation device used in said method. [Background technology]

[0002] When the high-voltage or extra-high-voltage cable 1 used for the underground power transmission line is laid in a manhole or handhole, as shown in FIG. 6, the cable 1 is bent into a snake shape before and after the connection part 3 in the handhole 2 to provide an offset part 4 in order to absorb the expansion and contraction of the cable 1 due to heat. If there is a difference in height in the conduit connecting the handhole 2, a large sliding force may be generated in the cable 1, which may affect the connection part 3. In addition, when vehicles run on a road above the underground track, the cable 1 may move due to the so-called surfing phenomenon caused by the multiple passing of the vehicles. In order to prevent such movement of the cable 1, movement restraint measures are taken using restraining devices such as cable cleats.

[0003] As a measure to restrain movement, cleats are used that apply pressure from the outside to pinch and hold the cable in place, but if the shielding layer of the cable is copper tape or copper wire, the pinching force must be 0.2 MPa or less for copper tape and 0.23 MPa or less for copper wire, otherwise the cable may be damaged. Therefore, if a single movement restraining device is not effective enough, multiple devices must be used in a row.

[0004] On the other hand, in recent years, renewable energy projects have been increasing, but when laying the private cables (underground power transmission cables) required for these, small hand holes and troughs are used, which means there is no space for additional measures to prevent the cable from moving due to the above-mentioned sliding or surfing phenomenon, and there are also cases where a sufficient offset is not provided. When lining up multiple cable cleats, it is necessary to extend the hand holes or U-shaped troughs or to carry out construction work to add more.

[0005] However, in designing the privately operated lines (underground power transmission lines) for the above-mentioned renewable energy business, although measures to counter the sliding force of the cable in the inclined pipeline can be considered in advance and sufficient measures can be taken, it is difficult to estimate the extent to which the moving force due to the surfing phenomenon, which cannot be considered in advance, should be estimated and whether measures should be taken.

[0006] In response to this, power companies regularly inspect the inside of manholes or handholes, and if any cable movement due to surf-riding is detected, appropriate restraining devices are installed and observed, and if the restraining force is insufficient, additional restraining devices are added to deal with the problem. However, in the current situation, inspections of manholes and handholes are rarely carried out in the aforementioned renewable energy projects. For this reason, there is a possibility that the restraining devices installed as a measure against surf-riding may be insufficient or excessive, and if there are too many, this will result in extra costs, but even if there is a shortage, work to stop power transmission and other response costs will be required.

[0007] Therefore, in addition to or instead of the cable restraint device, at many construction sites, manholes, handholes, etc. are filled with sand to prevent cable movement.

[0008] Even in the case of cable movement restraint devices that take measures against such cable slippage and surf-riding, if the movement restraining force is insufficient, it can lead to a cable destruction accident in the worst case scenario. Therefore, in cases where a device of this configuration is installed, the actual cable movement can be observed by digging up the buried sand, and if the amount of movement is large, measures such as adding more cable movement restraint devices can be taken.

[0009] Patent Document 1 discloses a device and method for measuring the amount of movement of a cable in a manhole, handhole, or the like.

[0010] The device disclosed in Patent Document 1 comprises a displacement sensor installed near a cable, a sensor wire pulled out in a predetermined direction from the displacement sensor via a pulley, and a wire fixing means for fixing the end of the sensor wire to the cable. The sensor wire is arranged parallel to the cable, and the movement measuring device measures the longitudinal extension of the cable via the sensor wire. In order to arrange the sensor wire parallel to the cable, the installation position of the displacement sensor and the fixing position of the sensor wire by the wire fixing means are adjustable. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 6867172 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0012] The device of Patent Document 1 can measure the amount of movement of a cable when sand is not filled inside a manhole, handhole, etc. However, if sand is filled after the device is installed, there is a risk that the sensor installed parallel to the cable will not respond correctly. For example, sand may get caught between the pulley that detects the movement of the sensor wire and the sensor wire, or sand may get inside the pulley, slowing down its movement and causing an incorrect determination of the amount of movement. In addition, the device as a whole has disadvantages such as being complicated and costly.

[0013] Therefore, the object of this invention is to provide a cable movement observation method and observation device which is extremely simple in construction and can reliably observe in manholes, handholes, etc. which have been filled with sand or which are filled with groundwater, while still remaining filled with the sand, etc. [Means for solving the problem]

[0014] The invention of claim 1 relates to a method for installing a cable leading out from a handhole, manhole, or U-shaped trough into a pipeline, the method comprising: providing an opening in a ceiling plate of the handhole, manhole, or U-shaped trough, covering the opening and providing a cylindrical housing having a height to the ground surface on the upper surface of the ceiling plate, covering an upper opening of the cylindrical housing with an opening-closing cover; providing a guide tube having an upper end fixed to the inner circumference of the cylindrical housing; and passing a lower portion of the guide tube through the opening in the ceiling plate to provide a handhole. In this cable movement observation method, the cable is pulled into a guide tube, a manhole, or a U-shaped trough, the pulled-in end is bent and curved in the longitudinal direction of the cable above the cable, one end of a wire is fixed to the outer periphery of the cable, the other end of the wire is passed through the guide tube and hung down outside the guide tube from the upper end of the guide tube, a mark is made on the wire where it protrudes from the upper end of the guide tube, the cable is left in this state for a certain period of time, and then the opening and closing lid is opened and the wire is extended upward. The degree to which the cable has been pulled in is measured based on the position of the mark.

[0015] The invention of claim 2 is a cable movement observation method according to the invention of claim 1, which comprises passing the other end of the wire into the guide tube and extending it upward from the upper end of the guide tube, hanging it on a first engagement portion provided at the upper inside part of the cylindrical casing and then hanging it downward, folding the other end back and extending it upward and fixing or engaging it with a second engagement portion at the upper inside part of the cylindrical casing, providing a scale in the longitudinal direction of the wire protruding from the upper end of the guide tube, leaving it in this state for a certain period of time, and then opening the opening / closing lid and removing the other end of the wire from the second engagement portion and the first engagement portion and extending it upward, measuring the degree to which the wire is retracted using the scale to measure the movement width of the cable.

[0016] The invention of claim 3 relates to a handhole, manhole or U-shaped trough in which a cable is led out into a pipeline from the handhole, manhole or U-shaped trough, and the inside of the handhole, manhole or U-shaped trough is filled with sand or filled with groundwater, and an opening is provided in the ceiling plate of the handhole, manhole or U-shaped trough, a cylindrical housing covering the opening and having a height to the ground surface is provided on the upper surface of the ceiling plate, the upper opening of the cylindrical housing is covered with an opening-closing lid, a guide tube having an upper end fixed to the inner circumference of the cylindrical housing is provided, and the lower part of the guide tube is passed through the opening of the ceiling plate to guide the handhole, manhole or U-shaped trough into the pipeline. The cable is pulled into either a hole or a U-shaped trough, the pulled-in end is curved and folded above the cable in the longitudinal direction of the cable, one end of a wire is fixed to the outer periphery of the cable, the other end of the wire is passed through the guide tube and extended upward from the upper end of the guide tube, hooked onto a first locking portion provided inside the cylindrical casing and then hung downward, the other end of the hanging wire is folded back and extended upward and fixed or locked to a second locking portion at the upper inside of the cylindrical casing, and a scale is provided in the longitudinal direction on the outer periphery of the wire protruding from the upper end of the guide tube.

[0017] In addition, the invention of claim 4 is a cable movement observation device as described in claim 3, in which one end of the wire is fixed to the outer periphery of the cable by wrapping a rubber plate around the outer periphery of the wire and tightening a number of tightening bands from above to fix the rubber plate to the cable, and one end of the wire is fixed to one of the tightening bands.

[0018] The invention of claim 5 is a cable movement observation device according to claim 4, in which both ends of the rubber plate wrapped around the cable are tapered. Effect of the Invention

[0019] According to the invention of claim 1, a method and device for observing whether or not the movement of the cable caused by the so-called surfing phenomenon caused by vehicles running on a road above an underground track is prevented in a place where the inside of a handhole, manhole, or U-shaped trough in which the cable is led out into a pipe from the inside of the handhole, manhole, or U-shaped trough is filled with sand to prevent the cable from moving, or in a place where the inside is filled with groundwater, can be realized with an extremely simple structure. The movement of the cable can be observed without damaging the cable, and the quality of the cable and the device used for the movement observation method can be maintained for a long period of time. Therefore, it becomes possible to take measures such as repairs to prevent cable destruction accidents, and a strong social infrastructure can be maintained.

[0020] In this case, a cylindrical tube is provided around an opening in the ceiling plate of either a handhole, a manhole, or a U-shaped trough, a guide tube is supported within the tube, and one end of a wire, one end of which is fixed to a cable inside either the handhole, the manhole, or the U-shaped trough, is passed through the guide tube and pulled out from the upper end of the guide tube. After leaving it in this state for a certain period of time, the opening and closing cover located on the ground of the cylindrical housing is opened, the other end of the wire is pulled up, and the mark position is measured, and the movement state of the cable can be known. If the movement is large, measures such as additional installation of the cable movement suppression device can be taken. Moreover, it is easy to observe without removing the sand filled in the manhole, handhole, etc., or the groundwater that fills it. In addition, with this method, electrical equipment or devices for photographing the movement of the cable, as well as a power source, are not required, and there is no problem with submersion in water.

[0021] In addition, according to the inventions of claims 2 and 3, since the wire is provided with a scale, the length of the wire that has been retracted can be easily measured, and the amount of cable movement can be measured more quickly and accurately.

[0022] According to the invention of claim 4, even if the cable undergoes thermal expansion and contraction in the cross-sectional direction, the rubber plate absorbs this, and one end of the wire can be fixed to the cable without damaging the outer periphery of the cable.

[0023] Furthermore, according to the invention of claim 5, when the cable is pulled into the pipeline, the end of the rubber plate is tapered or streamlined, so that the rubber plate does not deform and the cable and wire move reliably as one unit, enabling more accurate observation. [Brief description of the drawings]

[0024] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a cable movement observation device according to a first embodiment of the present invention. [Diagram 2] 1 is an enlarged cross-sectional view showing an upper part of a cylindrical housing of a cable movement observation device according to a first embodiment of the present invention. [Diagram 3]1 is an enlarged cross-sectional view of a state in which the opening / closing cover of a cylindrical housing of a cable movement observation device in accordance with a first embodiment of the present invention is open and the wire is pulled upward. [Figure 4] 1 is an enlarged front view showing the scale of the wire of the cable movement observation device of the first embodiment of the present invention. FIG. [Diagram 5] 1 is an enlarged front view of a state in which one end of a wire of a cable moving observation device in accordance with a first embodiment of the present invention is fixed to a cable. [Figure 6] 1 is a cross-sectional view of a handhole in which a cable movement observation device according to a first embodiment of the present invention is provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] (Embodiment Example 1) A moving cable observation device A according to a first embodiment of the present invention will be described with reference to Figs.

[0026] As shown in Fig. 1, this cable movement observation device A is a device that observes the movement of a cable 1 that is led out from a pipe entrance 5 to a pipe (not shown) in a handhole 2 provided in an underground power transmission line, and an opening 6 is provided in a ceiling plate 2a of the handhole 2, and a cylindrical housing 7 is fixed to the ceiling plate 2a so as to surround the opening 6. The upper end of this cylindrical housing 7 extends to the position of the ground surface GL, and an opening / closing cover 8 is provided at the upper end. In addition, the lower surface of the cylindrical housing 7 (water control valve box) rests on vibration-proof rubber 9 provided on the ceiling plate 2a, and the periphery is fixed with anchors 10.

[0027] Furthermore, the upper part of a guide tube 11 having a bent portion 11a at its lower end is supported inside the cylindrical housing 7, and the lower end of the guide tube 11 passes through the opening 6 and extends above the cable 1 in the handhole 2, with the bent portion 11a opening toward the pipe opening 5 just above the cable 1. The guide tube 11 penetrates the vibration-proof rubber 9. A rubber plate 12 is wrapped around the outer periphery of the cable 1 just before the pipe opening 5 in the handhole 2, and a plurality of tightening bands 13 are wrapped around the rubber plate 12 at intervals. The rubber plate 12 acts to absorb thermal expansion and contraction in the cross-sectional direction of the cable.

[0028] One end of wire 14 is fixed to one side of the tightening band 13, and the other end of wire 14 enters guide tube 11 through the opening of bent portion 11a at the lower end of guide tube 11, exits upper end 11b of guide tube 11, extends upward to first locking portion 15, which is the hinge portion under the opening / closing lid 8 inside the cylindrical casing 7, is hooked on first locking portion 15 and then hangs downward, descends below the upper end 11b of guide tube 11, bends back at that point, extends upward again, and is fixed by second locking portion 16 on the underside of the opening / closing lid 8.

[0029] 4, a scale 17 is provided in a certain range from the point where the wire 14 protrudes from the upper end 11b of the guide tube 11 to the other end. Before the other end of the wire 14 is hooked onto the first locking portion 15, the end of the wire 14 is pulled upward as shown in FIG. 3, and the scale 17 of the wire 14 is read and recorded using the position of the upper end of the cylindrical casing 7 with the opening / closing lid 8 opened as a reference point.

[0030] In addition, in the configuration in which one end of the wire 14 is fixed to the cable 1, as shown in Fig. 5, tape 18 is wound around both ends of the rubber plate 12, and the ends of the rubber plate 12 are formed into a tapered or streamlined shape. This allows the cable 1 to move smoothly within the packed sand, and therefore the wire 14 can also move reliably.

[0031] Moreover, the hand hole 2 is filled with sand 19 to prevent the cable from moving.

[0032] After a certain period of time in this state, it is determined whether or not the cable 1 has moved. At that time, as shown in Fig. 3, an operator opens the opening and closing cover 8 from the ground, removes the end of the wire 14 from the second locking portion 16 and the first locking portion 15, and pulls it up vertically. At that time, the scale 17 of the wire 14 is read at the position of the upper end of the cylindrical casing 7, and whether or not the cable 1 has been pulled into the conduit, or how far it has been pulled, is determined based on how far the wire 1 has been pulled in. If the amount of pull of the cable 1 is large, measures such as adding a cable movement restraining device can be taken.

[0033] In the above embodiment 1, the present invention has been described using a specific example of a handhole, but it can also be applied to manholes and U-shaped troughs. Also, in the above embodiment 1, a portion where measures are taken to prevent cable movement by filling sand 19 in handhole 2 is described, but even if such measures to prevent cable movement are not taken and groundwater happens to fill handhole 2, the present invention makes it easy to observe the amount of cable movement.

[0034] The other end of wire 14 may be left hanging down from upper end 11b of guide tube 11 to the outside of guide tube 11 for a certain period of time, or may be hung on first engaging portion 15 and left hanging down from there for a certain period of time. What is important is that wire 14 maintains a degree of freedom when being pulled in as cable 1 moves, and that the other end of wire 14 can be easily pulled up when an operator opens opening / closing lid 8 after being left for a certain period of time.

[0035] In addition, in the above embodiment 1, a rubber plate 12 is used to fix one end of the wire 14 to the cable 1, but the rubber plate 12 is not necessary. Furthermore, the front and rear ends of the rubber plate 12 to be fixed are tapered by wrapping tape 18 around them, but the rubber plate 12 may be tapered by, for example, shaving it without wrapping tape 18 around it, or it may not be tapered at all. [Explanation of symbols]

[0036] A Cable Mobile Observation Device 1 Cable 2 Hand hole 2a Ceiling panel 3 Connection part 4 Offset section 5 Pipe opening 6 Opening 7 Cylindrical housing 8 Opening and closing cover 9 Anti-vibration rubber 10 Anchor 11 Guide tube 11a Bent part 11b Upper end 12 Rubber plate 13 Fastening band 14 Wire 15 First locking portion 16 Second locking portion 17 Scale 18 Tape 19 Sand

Claims

1. In a location where a cable is installed from a handhole, manhole, or U-shaped trough into a pipeline, the inside of the handhole, manhole, or U-shaped trough has been filled with sand or filled with groundwater, An opening is provided in a ceiling plate of a handhole, a manhole, or a U-shaped trough, a cylindrical housing is provided on an upper surface of the ceiling plate to cover the opening and has a height to the ground surface, and an upper opening of the cylindrical housing is covered with an opening / closing lid, a guide tube having an upper end fixed to an inner periphery of the cylindrical housing, a lower portion of the guide tube being passed through an opening in the ceiling plate and pulled into a handhole, a manhole, or a U-shaped trough, and the pulled-in end portion being bent and curved in the longitudinal direction of the cable above the cable; one end of a wire having the other end fixed to the outer periphery of the cable is passed through the guide tube and hung downward from the upper end of the guide tube to the outside of the guide tube, and a mark is made on the wire at the point where it protrudes from the upper end of the guide tube; This cable movement observation method is characterized by leaving the cable in this state for a certain period of time, then opening the opening / closing cover and extending the wire upward, and measuring the degree to which the cable has been pulled in based on the position of the mark.

2. In the invention of claim 1, the other end of the wire is passed through the guide tube and extended upward from the upper end of the guide tube, hooked onto a first locking portion provided at the upper inside portion of the cylindrical housing and then hung downward, the other hanging end is folded back and extended upward and fixed or locked to a second locking portion at the upper inside portion of the cylindrical housing, and a scale is provided in the longitudinal direction of the wire protruding from the upper end of the guide tube, A cable movement observation method characterized by leaving the wire in this state for a certain period of time, then opening the opening / closing cover, removing the other end of the wire from the second and first locking portions and extending it upward, and measuring the degree to which the wire is pulled in using the scale to measure the amount of movement of the cable.

3. In a location where a cable is installed from a handhole, manhole, or U-shaped trough into a pipeline, the inside of the handhole, manhole, or U-shaped trough has been filled with sand or filled with groundwater, an opening is provided in a ceiling plate of a handhole, a manhole, or a U-shaped trough, a cylindrical housing covering the opening and having a height to the ground surface is provided on an upper surface of the ceiling plate, and an upper opening of the cylindrical housing is covered with an opening / closing lid; a guide tube having an upper end fixed to an inner periphery of the cylindrical housing, a lower portion of the guide tube being passed through an opening in the ceiling plate and pulled into a handhole, a manhole, or a U-shaped trough, and the pulled-in end portion being curved and bent in the longitudinal direction of the cable above the cable; one end of a wire is fixed to the outer periphery of the cable, the other end of the wire is passed through the guide tube, extended upward from the upper end of the guide tube, hooked onto a first locking portion provided inside the cylindrical housing, and then hung downward; the other end of the hanging wire is folded back, extended upward, and fixed or locked to a second locking portion at the upper inside portion of the cylindrical housing; A cable movement observation device, characterized in that a scale is provided in the longitudinal direction on the outer periphery of the wire protruding from the upper end of the guide tube.

4. 。 The cable movement observation device described in claim 3, characterized in that one end of the wire is fixed to the outer periphery of the cable by wrapping a rubber plate around the outer periphery of the wire and tightening a plurality of tightening bands from above to fix the rubber plate to the cable, and then fixing one end of the wire to one of the tightening bands.

5. 5. A cable movement observation device according to claim 4, wherein both ends of the rubber plate wound around the cable on the side of the pipeline are tapered.

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