Plug-in type power cable sealing end for repairing fault and method for repairing fault

Abstract

The present invention relates to a power cable sealing end for repairing a fault, and more particularly, to a power cable sealing end for repairing a fault by replacing a faulty part in an outdoor sealing end with a plug-in type sealing end. A plug-in type power cable sealing end for repairing a fault according to the present invention may comprise: an insulating tube which has an upper electrode formed at the top and a lower electrode formed at the bottom, and is filled on the inside with an insulating gas while connected; a conductor lead wire that is connected to the upper electrode and is the same length as the insulating tube; a conductor sleeve, the upper side of which has the conductor lead wire fastened thereto in a plug-in manner, and the lower side of which has a conductor of a power cable fastened thereto; a stress cone that is inserted at a certain position of an insulator of the power cable in order to mitigate an electric field; a bushing fastened to the stress cone while surrounding same, wherein the conductor sleeve is fitted on the upper side of the bushing, and an outer flange is connected to the lower side of the bushing; a compression ring compressed by an elastic spring for maintaining the interfacial pressure of the stress cone; and a lower copper pipe connected to the lower end of the compression ring.

Description

Plug-in type fault recovery power cable termination box and fault recovery method

[0001] The present invention relates to a power cable termination box for fault recovery, and more specifically, to a power cable termination box for fault recovery that replaces a faulty part in an aerial termination box with a plug-in type termination box.

[0002] The terminals of underground ultra-high voltage power cables are divided into gas-filled termination boxes (EB-G) used to connect underground cables and circuit breakers in indoor substations, etc., and air-filled termination boxes (EB-A) used to extend underground cables outside and connect them to overhead lines, circuit breakers, transformers, etc.

[0003] The air terminal connection box (Out Door Sealing End) covers the connected area with a magnetic or silicone material tube, and the length of the tube varies depending on the capacity of the ultra-high voltage cable and the interfacial electric field characteristics.

[0004] The length of the cable is formed from a short distance of 3000mm to a long distance of 5000mm, and the exposed part of the ultra-high voltage cable connected to it also becomes longer depending on the length of the cable.

[0005] The connected state of the aerial terminal connection box is such that the ultra-high voltage cable is positioned vertically with respect to the ground, and accordingly, the ultra-high voltage cable is also placed vertically. The ultra-high voltage cable has a structure in which the conductor at the tip is fixed by a conductor lead rod and the lower part is fixed by an external case connected to the cable tube.

[0006] A conventional aerial terminal connection box of this structure is disclosed in Korean Utility Model Registration No. 20-0123113, Korean Patent Registration No. 10-0401595, and Korean Patent Registration No. 10-1557988.

[0007] However, since the length of exposed power cables in the aerial terminal box is considerable, there is a problem that when a fault (insulation breakdown, etc.) occurs inside it, it must be completely dismantled and replaced with a new one.

[0008] In particular, in a situation where the power cable must be cut by several meters due to replacement of a faulty section in an existing underground power cable system, if there is no spare line, the problem of difficulty in fault recovery itself may arise.

[0009] [Prior Art Literature]

[0010] [Patent Document]

[0011] (Patent Document 1) Republic of Korea Registered Utility Model No. 20-0123113

[0012] (Patent Document 2) Republic of Korea Registered Patent No. 10-0401595

[0013] (Patent Document 3) Republic of Korea Patent No. 10-1557988

[0014] The present invention is intended to solve the above-mentioned problem, and to provide a fault recovery terminal connection box for fault recovery in an aerial terminal connection box in a power cable system, and a fault recovery method thereof.

[0015] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0016] In order to solve the above-described problem, a plug-in type power cable termination box for fault recovery according to the present invention may be formed of a tube having an upper electrode formed at an upper end, a lower electrode formed at a lower end, and an insulating gas filled inside in a connected state, a conductor lead wire connected to the upper electrode and having a length equal to the tube, a conductor sleeve to which the conductor lead wire is connected in a plug-in manner at an upper end and to which a conductor of a power cable is connected at a lower end, a stress cone inserted at a predetermined position of an insulator of the power cable for alleviating an electric field, a bushing to which the conductor sleeve is fitted at an upper end, connected to an external flange at a lower end, and connected by wrapping around the stress cone, a compression ring for compressing with an elastic spring for maintaining an interface pressure of the stress cone, and a lower copper tube connected to the lower end of the compression ring.

[0017] In addition, the plug-in type fault recovery power cable termination box according to the present invention is a termination box that cuts the power cable at the connection part of an aerial termination box for an underground power cable where a fault has occurred and processes the terminal of the cut power cable with a termination box, and replaces the power cable inserted into a tube to secure an electrical leakage distance of the aerial termination box with a conductor lead wire of the length of the power cable, and the inside of the tube is filled with insulating gas, and the conductor lead wire is connected to one side of a conductor sleeve in a plug-in manner, and the conductor of the power cable is connected to the other side of the conductor sleeve. It can have a structure.

[0018] Here, the plug-in type fault recovery power cable termination box may further include a stress cone inserted into a predetermined position of the insulation of the power cable for electric field relief, a bushing having the conductor sleeve fitted on the upper side and connected to an external flange on the lower side and fastened by wrapping the stress cone, a compression ring compressed by an elastic spring for maintaining the interface pressure of the stress cone, and a lower copper pipe connected to the lower end of the compression ring.

[0019] In addition, a plug-in type power cable termination box for fault recovery according to the present invention may have a structure in which a tube having an upper electrode formed at an upper end and a lower electrode formed at a lower end, a bushing inserted into the lower inner side of the tube, a conductor lead wire connecting the upper electrode at the upper end of the tube and the electrode at the upper end of the bushing to each other in a plug-in manner, and the electrode at the upper end of the bushing is connected to a conductor of a power cable, and an insulating gas is filled between the tube and the bushing.

[0020] In addition, a fault recovery method using a plug-in type fault recovery power cable termination box according to the present invention can be achieved through a process of disassembling components of an aerial termination box where a fault (insulation breakdown) has occurred, cutting off the terminal portion of a power cable already installed in an underground power cable system, performing a terminal treatment process of the power cable in the cut position on the underground power cable system, connecting the power cable conductor to one end of a conductor sleeve, then connecting a conductor lead wire to the other end of the conductor sleeve in a plug-in manner, connecting a stress cone to a predetermined position for alleviating the electric field of the power cable, connecting a bushing to the outside of the stress cone, inserting a fin of a previously installed aerial termination box with the conductor lead wire centered inside, installing the fin, and filling the inside of the fin with insulating gas for insulation.

[0021] In addition, a fault recovery method using a plug-in type fault recovery power cable termination box according to the present invention comprises: a fault diagnosis step in which a fault (insulation breakdown) occurs inside an aerial termination box already installed in an underground power cable system and a fault portion cutting step in which components of the installed aerial termination box are disassembled and a terminal portion of a power cable is cut; a power cable termination processing step in which a terminal processing process of the power cable is performed; a conductor lead wire connecting step in which a conductor lead wire is connected to the other end of the conductor sleeve in a plug-in manner after connecting the power cable conductor to one end of the conductor sleeve; a stress cone connecting step in which a stress cone is connected to a predetermined position for electric field relief of the power cable and is fixed at the rear by a compression ring; a bushing fastening step in which both sides of a flange portion of a previously inserted bushing are fastened and fixed to an external flange and a lower copper pipe is connected to the rear end of the compression ring; It can be performed by including a step of installing a pipe of an air terminal connection box that has been installed, inserting the conductor lead wire into the center of the inside, and then fastening a lower electrode formed at the bottom of the pipe to an external flange; and an insulating gas filling step of filling the inside of the pipe with insulating gas for insulation.

[0022] Here, the terminal processing step may include removing the aluminum sheath of the power cable, processing the semiconductor layer, sanding the insulator, and exposing the conductor.

[0023] According to the present invention, a fault recovery terminal connection box for fault recovery in an aerial terminal connection box in a power cable system and a fault recovery method thereof can be provided.

[0024] In addition, even when there is no spare power cable in an existing underground power cable system, a terminal connection box for failure recovery and a method for failure recovery thereof can be provided, which enable failure recovery by reconnecting only the terminal connection box without loss of the power cable.

[0025] However, the effects of the present invention are not limited to the above-described effects, and may be expanded in various ways without departing from the spirit and scope of the present invention.

[0026] FIG. 1 illustrates a power cable aerial termination connection box according to one embodiment of the present invention.

[0027] Figure 2 illustrates a failure point of a power cable aerial termination joint according to one embodiment of the present invention.

[0028] FIG. 3 illustrates a plug-in type fault recovery power cable termination box according to one embodiment of the present invention.

[0029] FIG. 4 is a flow chart of a fault recovery process using a plug-in type fault recovery power cable termination box according to one embodiment of the present invention.

[0030] The following detailed description of the present invention refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention, while different from each other, are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention. Furthermore, it should be understood that the positions or arrangements of individual components within each disclosed embodiment may be modified without departing from the spirit and scope of the present invention. Accordingly, the following detailed description is not intended to be limiting, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly described. Like reference numerals in the drawings designate the same or similar functionality throughout the several aspects.

[0031] FIG. 1 illustrates a power cable aerial termination connection box according to one embodiment of the present invention.

[0032] Referring to FIG. 1, the power cable aerial termination box of the present invention is a termination box used to extend a power cable (11) to the outside and connect it to an overhead line, circuit breaker, transformer, etc.

[0033] The power cable (11) is terminated by removing the exterior to expose the insulator (XLPE, Cross Linked Polyethylene, 12) to the designed length, and the conductor (13) of the power cable (11) from which the insulator (12) has been removed is exposed at the upper part of the insulator (12).

[0034] The power cable aerial termination joint is composed of a magnetic or conductor lead rod (21), a stress cone (22), a fixing bracket (23), a flange (24), a tube (25), and a lower copper tube (26).

[0035] The conductor lead rod (21) is inserted into the conductor (13) with the tip of the power cable (11) exposed, compressed or fastened, and electrically connected to the upper electrode of the conductor (25).

[0036] The stress cone (22) is positioned so as to slip on the cable insulator (12) and semiconducting layer of the power cable (11) with the aluminum sheath removed, prior to insertion and compression (or fastening) of the conductor lead (21).

[0037] The stress cone (22) is used to alleviate the interfacial electric field of the cable, and is formed of an insulating portion and a semiconducting portion using silicone material.

[0038] The stress cone (22) made of silicone has excellent elasticity, so when it is slipped down to the insertion position of the cable whose outer diameter is larger than the inner diameter of the stress cone (22) in a pre-inserted state, the inner diameter of the stress cone (22) increases due to elasticity, and it is completely attached to the cable.

[0039] The connector (25) is made of magnetic material or silicon material, and an upper electrode is formed on the upper side and connected to an upper shield (not shown), and a lower electrode is formed on the lower side and connected to a flange (24) via a fixing member (23), forming the exterior of a power cable aerial termination connection box while protecting the connection box and used as an insulating reinforcement material.

[0040] Among the terminal connection boxes of power cables, the connector (25) is exposed to the air, that is, the aerial terminal connection box, and the length of the connector used for external reinforcement is formed to be considerably long in consideration of the interface electric field characteristics of the air.

[0041] The interior of the love tube (25) is filled with air (30).

[0042] Figure 2 illustrates a failure point of a power cable aerial termination joint according to one embodiment of the present invention.

[0043] Referring to Figure 2, if a failure occurs at a specific location within the aerial terminal connection box, repair must be performed for that failure point (P).

[0044] The main cause of power cable failure is dielectric breakdown due to insulation deterioration of the power cable.

[0045] At this time, the failure of the aerial terminal connection box and the power cable must be repaired, but the aerial terminal connection box uses a pipe (25) with a relatively long leakage length due to insulation reinforcement due to aerial exposure, and at this time, a power cable (11) corresponding to the length of the pipe (25) is inserted.

[0046] In order to repair a relatively long power cable (11) from a failure, the length (L) from the connection point to the end must be cut and then reassembled.

[0047] However, since the power cable (11) has been cut in the already installed underground power system, it is necessary to pull the power cable (11) to use it, but in many cases, it is impossible or difficult to pull the power cable and reassemble it in the already installed underground power system.

[0048] In order to perform fault recovery in the state of the installed underground power cable without moving its location, the present invention can perform fault recovery using a fault recovery connection box as shown in Fig. 3 below.

[0049] FIG. 3 illustrates a plug-in type fault recovery power cable termination box according to one embodiment of the present invention.

[0050] As shown in FIG. 3, a power cable termination box for fault recovery according to one embodiment of the present invention is a plug-in type, and as shown in FIG. 2, a power cable having a fault point is cut and replaced, and a conductor lead wire (38) of the same length is used to replace the conductor (12) of the power cable (11).

[0051] The power cable termination box for fault recovery of the present invention comprises a conductor lead rod (21), a conductor sleeve (25), a stress cone (32), a compression ring (33), a flange (34), an epoxy (or silicone) bushing (35), a lower copper tube (36), an upper shield (37), and a conductor lead wire (38).

[0052] The conductor lead rod (21) is a conductor connected to overhead lines, circuit breakers, transformers, etc.

[0053] A conductor lead wire (38) can be connected between the conductor lead rod (21) and the conductor sleeve (31) in a plug-in type.

[0054] The conductor lead wire (38) is replaced by the cut length of the power cable where the fault point in Fig. 2 occurred.

[0055] As shown in Fig. 1, the inside of the tube (25) of the aerial terminal connection box is air-insulated, and the insulator (12) of the power cable (11) is formed as long as the length of the tube (25) so that the conductor is not exposed. However, in the power cable termination connection box for fault recovery, instead of replacing the length of the insulator (12) of the power cable (11) inside the tube (25) with a conductor lead wire (38), the space between the conductor lead wire (38) and the tube (25) can be filled with SF6 gas as an insulator.

[0056] After the plug-in connection of the conductor lead wire (38) and the conductor sleeve (31), an upper shield (37) can be placed to alleviate the electric field of the conductor connection.

[0057] The stress cone (32) is positioned so as to slip on the insulator (12) and semiconducting layer of the power cable (11) with the aluminum sheath of the power cable (11) removed, in a state where it is inserted before fastening the conductor sleeve (31).

[0058] The stress cone (32) is used to alleviate the interface electric field of the power cable (11), and is formed of an insulating portion and a semiconducting portion using silicone material.

[0059] The stress cone (32) is set to be larger than the inner diameter of the power cable (11) to maintain the interface pressure of the power cable (11) within the design range, and is inserted into the insulator and semiconducting layer of the power cable (11) while being stretched by elasticity, and a compression ring (33) is fastened to push the stress cone (32) by applying spring pressure.

[0060] Afterwards, a bushing (35) made of epoxy or silicone material is fitted, and a flange formed on the lower side of the bushing (35) is fixed by being connected to an external flange (34).

[0061] A lower copper tube (36) is attached to the lower part of the flange (34) to protect the internal connecting material.

[0062] A power cable termination box for fault recovery of this structure uses a conductor lead wire (38) to replace a cut power cable (11) having a fault point, and instead of replacing the conductor lead wire (38) inside the tube (25) as is, it is filled with insulating gas (SF6) to prevent insulation breakdown, and a stress cone (32), a compression ring (33), a flange (34), a bushing (35), a lower copper tube (36), and an upper shield (37) are used to recover from faults.

[0063] By doing this, it becomes possible to perfectly perform connection and fault recovery of the power cable at the cut location without having to pull the power cable by the length of the cut for fault recovery.

[0064] FIG. 4 is a flow chart of a fault recovery process using a plug-in type fault recovery power cable termination box according to one embodiment of the present invention.

[0065] Referring to FIG. 4, a fault recovery process using a plug-in type fault recovery power cable termination box of the present invention is described.

[0066] First, a fault (insulation breakdown, etc., see Figure 2) occurs inside an aerial termination box (EB-A, Figure 1) installed in an underground power cable system, and a fault diagnosis is performed (S41).

[0067] When a fault is diagnosed, the parts of the installed aerial terminal connection box are disassembled, and the terminal part of the power cable (11) (as long as the length L in Fig. 2, where the length L means the length cut for fault recovery) is cut (S42).

[0068] A terminal treatment process of a power cable (11) is performed to repair a fault. The terminal treatment process may be a preliminary process prior to connection to a junction box, which may include removal of the aluminum sheath of the power cable, semiconductor layer treatment, sanding of the insulator (12), and exposure of the conductor (13) (S43).

[0069] After connecting the power cable conductor (13) to one end of the conductor sleeve (31), the conductor lead wire (38) prepared according to the design of the length of the connector (25) and the connection length is connected to the other end of the conductor sleeve (31) in a plug-in manner (S44).

[0070] At this time, internal insulating parts (stress cone (32), compression ring (33), flange (34), bushing (35), lower copper pipe (36), etc.) are inserted in advance before connecting the conductor.

[0071] According to the design criteria, the stress cone (32) is connected to the correct position and the rear is fixed by the compression ring (33) (S45).

[0072] Both sides of the flange portion of the inserted bushing (35) are fastened to the flange (34), the lower copper pipe (36) is connected to the rear end of the compression ring (33) (S46), and then bonding work is performed between the lower end of the lower copper pipe (36) and the outer covering of the power cable (11).

[0073] The previously installed air terminal connection box's fin (25) is used as is, the fin (25) is inserted with the conductor lead wire (38) centered on the inside, and the lower electrode formed at the bottom of the fin (25) is fastened to the external flange (S47).

[0074] With all the components of the connection box connected, SF6 gas (40) is filled inside the tube (25) for insulation (S48). A vacuum process may be performed before filling.

[0075] By doing this, the power cable of only the fault area can be cut without pulling the installed underground power cable (11), and complete recovery can be performed through a fault recovery terminal connection box via a conductor lead wire (38) of the same length (S49).

[0076] The features, structures, effects, etc. described in the embodiments above are included in one embodiment of the present invention, and are not necessarily limited to that one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified to implement other embodiments by those skilled in the art. Therefore, the contents related to such combinations and modifications should be construed as being included within the scope of the present invention.

[0077] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

[0078] [Explanation of symbols]

[0079] 11: Power cable

[0080] 12: Insulator

[0081] 13: Conductor

[0082] 21: Conductor withdrawal rod

[0083] 22, 32: Stress cone

[0084] 23: Support bracket

[0085] 24, 34: Flange

[0086] 25: Aegwan

[0087] 26, 36: Lower East Wing

[0088] 30: Air

[0089] 31: Conductor sleeve

[0090] 33: Compression ring

[0091] 35: Bushing

[0092] 37: Upper shield

[0093] 40: SF6 gas

Claims

1. A tube in which an upper electrode is formed at the top, a lower electrode is formed at the bottom, and an insulating gas is filled inside while in a connected state. A conductor lead wire having a length equal to that of the above-mentioned tube and connected to the above-mentioned upper electrode, A conductor sleeve to which the conductor lead wire is connected in a plug-in manner on the upper side and to which the conductor of the power cable is connected on the lower side, A stress cone inserted into a predetermined location of the insulator of the above power cable to relieve electric fields, A bushing having the conductor sleeve fitted on the upper side, connected to an external flange on the lower side, and fastened by wrapping the stress cone, A compression ring that compresses with an elastic spring to maintain the interface pressure of the above stress cone, A plug-in type fault recovery power cable termination box, comprising a lower tube connected to the lower end of the above compression ring.

2. The power cable at the connection point of the aerial termination box for the underground power cable where a fault has occurred is cut off, and the terminal of the cut power cable is processed as a termination box. In order to secure the electrical leakage distance of the aerial terminal connection box, the power cable inserted into the inner tube is replaced with a conductor lead wire of the length of the power cable, and the inner tube is filled with insulating gas. A plug-in type fault recovery power cable termination box, wherein the conductor lead wire is connected to one side of a conductor sleeve in a plug-in manner, and a conductor of a power cable is connected to the other side of the conductor sleeve.

3. In paragraph 2, A stress cone inserted into a predetermined location of the insulator of the above power cable to relieve electric fields, A bushing having the conductor sleeve fitted on the upper side, connected to an external flange on the lower side, and fastened by wrapping the stress cone, A compression ring that compresses with an elastic spring to maintain the interface pressure of the above stress cone, A plug-in type fault recovery power cable termination box further comprising a lower copper tube connected to the lower end of the compression ring.

4. A tube in which the upper electrode is formed at the top and the lower electrode is formed at the bottom, A bushing inserted into the lower inner side of the above-mentioned pipe, A conductor lead wire that connects the upper electrode at the top of the above-mentioned tube and the electrode at the top of the above-mentioned bushing in a plug-in manner, The electrode at the top of the above bushing is connected to the conductor of the power cable, A plug-in type fault recovery power cable termination box having a structure in which insulating gas is filled between the above-mentioned tube and the above-mentioned bushing.

5. Dismantle the parts of the aerial terminal connection box where a failure (insulation breakdown) has occurred, and cut off the terminal part of the power cable installed in the underground power cable system. In the above-mentioned underground power cable system, the terminal processing process of the power cable is performed in the cut position and in that state, After connecting the above power cable conductor to one end of the conductor sleeve, the conductor lead wire is connected to the other end of the conductor sleeve in a plug-in manner. To relieve the electric field of the above power cable, a stress cone is connected to a predetermined position, and a bushing is fastened to the outside of the stress cone. After inserting the conductor lead wire into the previously installed aerial terminal connection box with the inner center as the center, install the above-mentioned tube. A fault recovery method using a plug-in type fault recovery power cable termination box, which comprises a process of filling the inside of the above-mentioned tube with insulating gas for insulation.

6. A fault diagnosis stage in which a fault (insulation breakdown) occurs inside an aerial termination box installed in an underground power cable system and fault diagnosis is performed; A faulty section cutting step in which the parts of the installed aerial terminal connection box are dismantled and the terminal part of the power cable is cut off; A power cable terminal treatment step for performing a terminal treatment process of the above power cable; A conductor lead connection step of connecting the power cable conductor to one end of a conductor sleeve and then connecting a conductor lead to the other end of the conductor sleeve in a plug-in manner; A stress cone connection step of connecting a stress cone to a predetermined position to relieve the electric field of the above power cable and fixing the rear side thereof with a compression ring; A bushing fastening step of fastening and fixing both sides of the flange portion of the inserted bushing to an external flange and connecting the lower pipe to the rear end of the compression ring; A step for installing a pipe by inserting the previously installed air-end connection box with the conductor lead wire centered inside, and then connecting the lower electrode formed at the bottom of the pipe to an external flange; and A fault recovery method using a plug-in type fault recovery power cable termination box, comprising an insulating gas filling step of filling the inside of the above-mentioned tube with insulating gas for insulation.

7. In paragraph 6, A fault recovery method using a plug-in type fault recovery power cable termination box, wherein the above terminal processing step includes the processes of removing the aluminum sheath of the power cable, processing a semiconductor layer, sanding an insulator, and exposing a conductor.

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