KR101861491B1 - Method for Checking and Repairing of Underground Low Voltage Joint-box - Google Patents

Abstract

The present invention relates to a method for checking and repairing a underground low voltage connection box, which comprises: a first step of checking a state of a rubber packing of an inner insulation rubber plate after uncovering an upper cover of a underground low voltage connection box; a second step of measuring the temperature of a connection member for each phase; a third step of measuring leakage current and ground voltage by using a voltage meter after taping a helix with a silver foil; a fourth step of removing the silver foil when the leakage current and ground voltage measured in the third step are equal to or greater than 10 mA, and 25 V, respectively, cleaning the same with an electro contact cleaner which is a cleaning agent, spraying a liquid electrical insulation which is a coating agent thereto, having an insulation wire mounted and connected to left and right helices, covering an insulation contraction tube thereon, and heating, sealing, and reinforcing the same; and a fifth step of measuring the temperature in the second step and the leakage current and ground voltage in the third step again, and determining abnormality to terminate an operation. According to the method, a reinforcement work such as inspection or replacement of a defect portion and a connection member can be efficiently performed through a measurement result of the ground voltage and leakage current of a underground low voltage connection box in a live wire state, thereby securing the safety of facilities. Moreover, dust in the underground low voltage connection box is removed by using an electrical contact cleaner which is a cleansing agent, thereby preventing an accident due to a fire or short circuit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of checking and repairing an underground low-

The present invention relates to a method of inspecting and repairing an underground low-voltage connection box. More specifically, the method of inspecting and repairing underground low-voltage connection box that can prevent safety accident and safety accident by performing reinforcement work such as replacement of defective site and connection material through measurement result of ground voltage and leakage current of underground low- .

An underground low-voltage connection box is an electrical installation necessary for interconnection of underground cables. Specifically, it is used to connect low-voltage cables to underground distribution lines in the ground or buried in a branching place. It is covered with steel lid.

In recent years, due to the importance of the beauty of urban areas, the underground low voltage connection box has been increasing in installation place every year due to the undergrounding of the wiring line. It is installed in branch connection or straight line connection point of underground low-voltage cable, entry point of underground low-pressure customer, and other necessary site for other site conditions. Among them, trunk lines are mainly installed on back roads with frequent passage of people and heavy traffic, and on the premises of customers for incoming traffic. As of the end of 2016, more than 110,000 lines are installed nationwide.

In existing underground low-voltage connection boxes, there is a risk of general safety accidents in case of failure due to overheating of connection points and dropout of lids due to changes in operating environment. The inspection methods include the installation condition of the connection material during the heavy rain, the conformity through the measurement of the leakage current and the ground voltage, the damage of the junction box and the attachment of dirt, the grounding condition of the frame and the insulation rubber plate installation. Immediate reinforcement of these equipment is required after inspection, in the case of joints, lids, frame grounding and insulation.

As a related art related to this, Japanese Patent Laid-Open Publication No. 2000-005450 discloses an underground low voltage electric field shielding type connection material. However, the above invention relates to an underground low voltage line connecting material which connects a low voltage line in an underground wiring line, . Patent Document 002 discloses a " waterproof connection method of a flexible pipe and an underground ship ", which connects a flexible pipe for introducing a cable to a side wall of a subway such as a hand hole in a reliable sealed state, . Compared to the underground low-voltage connection box of the present invention, the above-mentioned patent document is similar in terms of waterproofing treatment to the connection site, but there is a large difference in overall.

Therefore, it is necessary to develop a new technique for securing safety through inspection and reinforcement of underground low-voltage connection boxes and further preventing safety accidents.

Korean Registered Patent No. 10-1680011 (November 21, 2016) Japanese Patent Application Laid-Open No. 6-193086 (July 12, 1994)

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method of inspecting and repairing an underground low-voltage connection box that can secure safety through inspection and reinforcement of an underground low-voltage connection box and further prevent a safety accident.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides: 1) a first step of checking the state of a rubber packing of an insulating rubber plate of an interior after removing an upper lid of an underground low- 2) a second step of measuring the temperature of each connection member; 3) a taping of the spiral to the tin foil, and then a leakage current and a ground voltage are measured by a voltage ammeter; 4) When the leakage current measured in the third step is 10 mA and the ground voltage is 25 V or more, the silver foil is removed and cleaned with an electro contact cleaner, which is a cleaning agent, to form a liquid Electrical Insulation) is sprayed, then the insulation wires are attached to the left and right spiral wires, and then the insulation shrink tube is covered and then heated and sealed to reinforce the fourth step. 5) a fifth step of measuring the temperature of the second step, the leakage current and the ground voltage of the third step again, determining whether there is an abnormality, and terminating the operation of the underground low voltage connection case ≪ / RTI >

Means for solving the other specific problems according to the present invention are described in the detailed description of the invention.

The inspection and repair method of the underground low-voltage connection box according to the present invention can efficiently perform the reinforcement work such as inspection and replacement of defective parts and connection materials through measurement results of the ground voltage and leakage current of the underground low- And furthermore, the dust in the underground low-pressure connection box is removed through the use of the electro-contact cleaner, which is a cleaning agent, so that there is an advantage that a safety accident due to a fire or a short circuit can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a schematic structure of a general underground low-pressure connection box. FIG.
2 is a block diagram showing a schematic operation sequence of a method of checking and repairing an underground low-voltage connection box according to the present invention.
3 is a view showing the internal structure of an underground low-pressure connection box according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention can be modified in various forms, and the scope of the present invention should not be construed as being limited to the following embodiments. This embodiment is provided to more fully illustrate the present invention to those skilled in the art. Therefore, the shape and detailed configuration of elements in the drawings have been simplified for explanation. It is to be understood that the terminology used herein is for the purpose of describing preferred embodiments of the present invention.

FIG. 1 is a block diagram showing a schematic structure of a general underground low-voltage connection box, FIG. 2 is a block diagram showing a schematic operation sequence of a method for inspecting and repairing an underground low-voltage connection box according to the present invention, Pressure connection box. Fig.

1, the structure of a general underground low-voltage connection box includes a lid 4, an insulating rubber plate 3, a frame 2, a cable 5, a connection member 1, a ground 2- 1).

The lid 4 and the frame 2 are preferably reinforced plastic (GFRP) having sufficient strength, durability and insulation as the material of the lid 4 and the frame 2, Since it is not insulated, there is a risk of electric shock accident.

An insulating rubber plate 3 is inserted between the lid 4 and the frame 2. A rubber packing (not shown) having an insulating and waterproof function is sealed between the insulating rubber plate 3 and the frame 2, Is inserted.

In the frame 2 of the underground low-voltage connection box, a plurality of cables 5 are connected by the connection member 1, and the lower portion is grounded 2-1 underground.

3, the cables 5 are connected to each other through the connection member 1, and in order to prevent the operator from electric shock in the live state, the insulated electric wire 9 is supported by the fastening clip 8 Respectively.

It is also preferable that the spiral 6, the connection member 1, the fastening clip 8 and the insulated electric wire 9 are tightly sealed with the insulating shrink tube 7 for insulation and waterproofing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, each step of the " method for inspecting and repairing an underground low-voltage connection box " according to the present invention will be described in detail.

The "method for inspecting and repairing the underground low-voltage connection box" according to the present invention comprises the steps of: 1) checking the state of the rubber packing of the inner insulating rubber plate after removing the upper lid of the underground low- 2) a second step of measuring the temperature of each connection member; 3) a taping of the spiral to the tin foil, and then a leakage current and a ground voltage are measured by a voltage ammeter; 4) When the leakage current measured in the third step is 10 mA and the ground voltage is 25 V or more, the silver foil is removed and cleaned with an electro contact cleaner, which is a cleaning agent, to form a liquid Electrical Insulation) is sprayed, then the insulation wires are attached to the left and right spiral wires, and then the insulation shrink tube is covered and then heated and sealed to reinforce the fourth step. 5) a fifth step of measuring the temperature of the second step, the leakage current and the ground voltage of the third step again, determining the abnormality, and terminating the operation.

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First, the first step is a preparation step of a "method for inspecting and repairing an underground low-voltage connection box" according to the present invention. The first step is to remove the upper lid 4 of the underground low-voltage connection box, (Without reference numerals) is complete. If the rubber packing is broken, the insulation rubber plate 3 is not sealed and the waterproof function is lost, so that the insulation is not provided.

The second step is a step of measuring the temperature of each connection member 1 formed in the frame 2, and the temperature of the connection member 1 is measured by using a thermal image thermometer or an infrared thermometer. At this time, the installation state of the connection member (1) is checked, and if the measurement temperature is high, the connection is poor and the connection is poor, so the connection should be completely tightened to maintain the ambient temperature.

The third step is to measure the leakage current and the ground voltage with a voltage ammeter after tapping the spiral wire 6 with a tin foil. After tapping the spiral wire 6 with the tin foil, the leakage current between the ground 2-1 (1), lid (4), and ground (2-1) are immediately replaced when the leakage current exceeds 10 mA and the ground voltage exceeds 25 V at the same time. Should be reinforced. The voltage ammeter used at this time is not particularly limited, but it is preferable to use an analog voltage ammeter.

In the fourth step, if the leakage current measured in the third step is 10 mA and the ground voltage is 25 V or more, the silver foil is removed, washed with a cleaning agent, sprayed with a coating agent, and insulated wires are attached to the left and right spiral wires After the insulation shrink tube is covered, it is heated and sealed to reinforce it. Specifically, when the leakage current measured in the third step is 10 mA and the ground voltage is 25 V or more, the connection state of the connection member 1 is not good, so that heat is generated or a bolt is loosened, And the like. In order to reinforce this, the silver foil is removed, and the area of the connection member 1 is cleaned with a cleaning agent, and then the coating agent is sprayed. Then, by inserting and connecting the insulated electric wire 9 to the left and right helix 6, the electric current is dispersed so that the repair work can be performed even in the live state. Then, the insulated shrink tube 7 It is preferable to tightly seal and reinforce it by heating (see Fig. 2).

The cleaning agent used is Electro Contact Cleaner (ECC-90, manufactured by Ilshin CNA Co., Ltd.). It is excellent in electrical insulation and does not leave any residue or condensate after use. It is noncorrosive. It is a dust remover that has many advantages such as being able to do. In addition, the coating agent is a liquid electrical insulation (Liquid Electrical Insulation, manufactured by Nanoprotech, USA), which is capable of long-term protection from moisture, and has excellent advantages such as instantaneous insulation resistance and conductivity.

Finally, as in the second and third steps, the temperature, the leakage current, and the ground voltage are measured again, and if the leakage current is 10 mA and the ground voltage is less than 25 V, , Check whether there is an abnormality in the connection, and finish the work when it is confirmed that there is no abnormality.

As described above, the inspection and repair method of the underground low-voltage connection box according to the present invention efficiently performs the reinforcement work such as inspection and replacement of defective parts and connection materials through measurement result of ground voltage and leakage current of underground low- Thereby securing the stability of the facility. Furthermore, the dust in the underground low-pressure connection box is removed through the use of the electro-contact cleaner, which is a detergent, to prevent safety accidents caused by fire or short-circuit.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . Accordingly, it should be apparent that the true scope of the present invention is defined by the following claims.

1: connection member 2: frame
2-1: Ground 3: Insulated rubber plate
4: Lid 5: Cable
6: Helical 7: Insulated shrink tube
8: Fastening clip 9: Insulated wire

Claims (5)

1) a first step of checking the state of the rubber packing of the inner insulation rubber plate after removing the upper lid of the underground low-pressure connection box;
2) a second step of measuring the temperature of each connection member;
3) a taping of the spiral to the tin foil, and then a leakage current and a ground voltage are measured by a voltage ammeter;
4) When the leakage current measured in the third step is 10 mA and the ground voltage is 25 V or more, the silver foil is removed and cleaned with an electro contact cleaner, which is a cleaning agent, to form a liquid Electrical Insulation) is sprayed, then the insulation wires are attached to the left and right spiral wires, and then the insulation shrink tube is covered and then heated and sealed to reinforce the fourth step.
5) a fifth step of measuring the temperature of the second step, the leakage current and the ground voltage of the third step again, determining whether there is an abnormality, and terminating the operation of the underground low voltage connection case Way.
The method according to claim 1,
Wherein the temperature measurement in the second step is performed with a thermal image thermometer.
The method according to claim 1,
Wherein the temperature measurement in the second step is performed using an infrared thermometer.
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