JP4887042B2 - Insulation recovery method - Google Patents

Description

  The present invention relates to an insulation recovery method for electrical equipment, and more particularly to an insulation recovery method in the case where insulation is lowered due to contamination of an insulator.

  In many electric devices, a cable is used to supply electric power from outside and to exchange electric signals with the outside. When connecting such a cable and electrical equipment or connecting cables, a terminal block is often used from the viewpoint of simplifying work.

  In the terminal block, a conductor plate having a plurality of screw holes is arranged at a predetermined interval via an insulator. A plurality of cables are screwed to the conductor plate via connection terminals having holes of a predetermined size that are attached to the ends of the respective cables, so that they can be electrically connected to electrical equipment or other cables. Connected to. By using such a terminal block, there is an advantage that electrical equipment can be installed quickly, and restoration (replacement) work can be performed quickly when the cable is damaged.

  Generally, the terminal block is disposed at the lower part of the device from the viewpoint of work and safety, and dust and dust are likely to accumulate. Due to the accumulation of dust or dust, a leakage current is generated on the surface of the insulator between the conductor plates constituting the terminal block, resulting in a problem that the insulation between the adjacent conductor plates, that is, between the adjacent cables is lowered. For the same reason, there also arises a problem that the insulation between the conductor plate and the terminal block fixing member, that is, the insulation between the cable and the ground is lowered. Such a phenomenon is also called a “tracking phenomenon”.

  In addition, seawater or river water may enter the installation site of electrical equipment due to storm surges or river floods when typhoons arrive. In such a case, the terminal block that is often arranged in the lower part of the electric device is flooded. Once submerged, even if it is sufficiently dry, conductive fouling contained in seawater and river water will adhere, reducing the insulation between cables and the insulation between cables as well as dust and dust accumulation. Problem arises.

  For this reason, conventionally, accumulation of dust or dust is removed by cleaning work such as brushing or air blow, while washing with water or water vapor is performed when submerged by seawater or river water.

In recent years, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-176500 (Patent Document 1), a cleaning agent including an alcohol aqueous solution having higher cleaning power and drying property has been proposed. According to the cleaning agent disclosed in Patent Document 1, it is possible to suppress the occurrence of corrosion in the cleaned electrical equipment and the like and to shorten the drying time.
JP 2003-176500 A

  The above-described electrical equipment includes power transmission / distribution equipment for supplying power to general households and factories, and electrical equipment used for such power transmission / distribution equipment is required to be restored as soon as possible.

  However, the conventional cleaning with water or steam has a problem that a long drying time is required. In addition, when the cleaning agent disclosed in Patent Document 1 described above is used, although the drying time can be shortened as compared with the conventional case, a liquid draining process for blowing off the cleaning agent and for complete drying. This drying process was necessary and was not sufficient to realize a quick recovery at the site.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide an insulation recovery method for quickly recovering insulation when the insulation is deteriorated due to contamination of the insulator. .

  According to the present invention, in an electrical apparatus including a plurality of current-carrying parts insulated from each other via an insulator, the insulation recovery method is used when the insulator is soiled. The insulation recovery method according to the present invention includes a step of cleaning the fouling matter adhering to the insulator by spraying the cleaning agent, the cleaning agent being 55 to 65 mass% isohexane and 5 to 10 mass%. It contains ethanol, 1 to 5% by mass of n-hexane, and 1 to 5% by mass of acetone.

  Preferably, the cleaning step comprises brushing the insulator so as to separate the fouling material from the insulator.

  Preferably, the method further includes a step of wiping off the remaining cleaning agent after the cleaning step is completed.

  According to this invention, the cleaning agent exhibits a cleaning effect on the oily and ionic fouling substances and has high drying properties. Accordingly, it is possible to realize an insulation recovery method that quickly recovers insulation when insulation is reduced due to contamination of the insulator.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is an external view of a terminal block 1 which is an example of an application target of an insulation recovery method according to the present invention.
Referring to FIG. 1, terminal block 1 includes, as an example, three pairs of terminal ports so that cables for three phases (a phase, b phase, and c phase) can be connected. The terminal block 1 includes the conductor plates 2a, 2b, and 2c corresponding to the respective phases and the tightening screws 4.1a and 4.2a that are screwed into the screw holes provided in the conductor plates 2a, 2b, and 2c, respectively. , Tightening screws 4.1b, 4.2b, and tightening screws 4.1c, 4.2c.

  For example, when two cables corresponding to the a phase are connected, a connection terminal (not shown) having a hole of a predetermined size attached to one end of each cable is connected to the conductor plate 2a and the fastening screws 4. 1a and between the conductor plate 2a and the fastening screw 4.2a and tighten. Then, the two cables are electrically connected via the conductor plate 2a. The same applies to the other phases. Note that the connection terminal is referred to as a crimp terminal, a compression terminal, or the like, depending on a method of attaching the cable.

  Furthermore, the terminal block 1 further includes an insulating mount 6 that supports the conductor plates 2a, 2b, and 2c, and insulating partitions 8 that are disposed on both sides of the conductor plates 2a, 2b, and 2c, respectively. The insulating mount 6 realizes insulation between the conductor plates 2a, 2b, and 2c, and the insulating partition 8 prevents a decrease in insulation and a short circuit due to accumulation of dust and dust.

  As shown in FIG. 1, in a general terminal block, since a plurality of pairs of terminal ports are continuously connected and arranged, even if they are separated from each other by an insulating partition wall 8, the absolute distance interval between them. Is short. For this reason, when conductive fouling substances adhere to the surfaces of the conductor plate and the insulating partition wall due to inundation with seawater or river water, a leakage current flows on the surface.

  Therefore, in the insulation recovery method according to the present invention, a cleaning agent having a high cleaning effect and a high drying property is sprayed onto the terminal block 1 to adhere to the surfaces of the conductor plates 2a, 2b, 2c, the insulating mount 6 and the insulating partition wall 8. Wash the debris.

  The cleaning agent used in the insulation recovery method according to the present invention is 55 to 65 mass% isohexane, 5 to 10 mass% ethanol, 1 to 5 mass% n-hexane, and 1 to 5 mass% acetone. including. Further, the remaining components include liquefied petroleum gas (LPG: Liquefied Petroleum Gas), butane, carbon dioxide and the like as propellants.

  In this cleaning agent, isohexane mainly exhibits a cleaning effect on oily fouling substances, and ethanol mainly exhibits a cleaning effect on ionic fouling substances. Acetone mainly emulsifies isohexane and ethanol.

FIG. 2 is a diagram showing a processing flow of the insulation recovery method according to the present invention.
FIG. 3 is a diagram showing an outline of the process of the insulation recovery method according to the present invention.

  With reference to FIG. 2 and FIG. 3, the operator sprays the cleaning agent on the workpiece such as the terminal block 1 (step ST1). In addition, it is desirable that the cleaning agent is filled in the spray can 30 or the like including the propellant. By increasing the spraying pressure, the contaminants can be separated and cleaned more effectively. At the same time, the operator brushes the surface so as to separate the adhered dirt (step ST2). That is, the operator brushes the surroundings of the insulating mount 6, the insulating partition wall 8, the tightening screws 4.1 a, 4.2 a, 4.1 b, 4.2 b, 4.1 c, 4.2 c with the brush 32, Promotes the separation of fouling material adhering to the surface.

  Thereafter, when spraying of the cleaning agent for a predetermined time is completed, the operator wipes off the remaining cleaning agent (step ST3). The remaining cleaning agent contains a fouling material separated from the insulating material. By wiping with a waste cloth 34 or the like, the fouling material can be removed more effectively, and more effective insulation recovery can be realized.

  According to the processing flow as described above, the insulation of the terminal block 1 that is the object to be processed can be recovered.

  In spraying the cleaning agent, the remaining cleaning agent can be reduced and more effective by inclining the sprayed surface of the object to be processed so that the cleaning agent after spraying flows down.

Hereinafter, the result verified about the effect of the cleaning agent concerning the present invention is explained.
FIG. 4 is a schematic configuration diagram of the verification apparatus 10 for verifying the effect of the cleaning agent according to the present invention.

  Referring to FIG. 4, using verification apparatus 10, a verification experiment was conducted on the insulation recovery effect by the insulation recovery method according to the present invention and the insulation recovery effect by the conventional water recovery method. The verification apparatus 10 includes the same simulated electric circuits 12.1 and 12.2. Simulated electric circuits 12.1 and 12.2 are to be processed terminal blocks 16.1 and 16.2, measurement terminal blocks 18.1 and 18.2, cables 14.1 and 14.2, respectively. It consists of rails 15 and 17 and a short-circuit cable 19.

  The terminal blocks 16.1 and 16.2 to be processed are supported on the support rails 15 and are arranged below the verification device 10 and immersed in a water tank 22 filled with seawater for a predetermined time, and then insulated. It is a terminal block on which recovery processing is performed. On the other hand, the measurement terminal blocks 18.1 and 18.2 connected through the cables 14.1 and 14.2, respectively, are terminals for measuring the resistance values of the terminal blocks to be processed 16.1 and 16.2. It is a stand. That is, the resistance value in the to-be-processed terminal block 16.1, 16.2 is measured using the insulation resistance meter 20 connected to the measurement terminal blocks 18.1, 18.2. Further, the measurement terminal blocks 18.1 and 18.2 are carried on the support rails 17 and are disposed on the verification device 10.

  The support rails 15 and 17 are made of a conductive material and are electrically connected to each other via a short-circuit cable 19. Furthermore, since the short-circuit cable 19 is electrically connected to the ground potential GND, the potentials of the support rails 15 and 17 can be regarded as the ground potential GND.

  The insulation resistance meter 20 is also referred to as a megger, and is a device that applies a predetermined DC voltage between the ground and the terminal or between the terminals, and calculates an insulation resistance value from a current value generated at that time. Specifically, when measuring the resistance to ground, one of the measurement cables of the insulation resistance meter 20 is in pressure contact with a target terminal, and the other measurement cable is in pressure contact with the support rail 17 and then the direct current voltage. Apply. Further, when measuring the interphase resistance value, a DC voltage is applied after the respective measurement cables of the insulation resistance meter 20 are in pressure contact with the respective terminals. In the embodiment of the present invention, the DC voltage applied between the ground and the terminals is set to 500V.

  As a verification method, the verification apparatus 10 is lowered, and the terminal blocks 16.1 and 16.2 to be processed are immersed in the water tank 22 disposed therebelow for a predetermined time. By lowering the verification apparatus 10 as a whole, the immersion time of the terminal blocks to be processed 16.1 and 16.2, ie, the fouling conditions can be made the same. After immersion for a predetermined time, the insulation recovery method according to the present invention and the conventional insulation recovery method are performed on the terminal blocks 16.1 and 16.2, respectively. In addition, about immersion time, it was set as 2 types of 1 hour and 5 minutes.

FIG. 5 is a diagram showing insulation recovery characteristics after treatment when the immersion time is 1 hour.
FIG. 5A shows resistance values between the grounds (average resistance values between the terminals of the respective phases and the ground).

  FIG. 5B shows interphase resistance values (average of resistance values between ab phase, bc phase, and ca phase).

  Referring to FIG. 5 (a), the terminal block 16.1 processed according to the insulation recovery method according to the present invention recovered to a resistance value of about 500 MΩ in 1 hour after the processing, and thereafter has a high resistance. Keep the value. If it recovers to about 500 MΩ, energization (eg, 440 V) is possible, and it can be determined that sufficient insulation recovery has been performed.

  On the other hand, the to-be-processed terminal block 16.2 processed according to the conventional insulation recovery method has a resistance value of less than 1 MΩ even after 3.5 hours of processing, and cannot be energized. That is, it can be determined that insulation recovery has not been performed. And the to-be-processed terminal block 16.2 was able to exceed the resistance value of 100 M (ohm) 7.5 hours after a process.

  As described above, based on the time when the resistance value exceeds 100 MΩ, the insulation recovery method according to the present invention achieves insulation recovery more than 7.5 times faster than the conventional insulation recovery method. it can.

  Referring to FIG. 5B, similarly to FIG. 5A, the terminal block 16.1 processed according to the insulation recovery method according to the present invention has a resistance value of up to about 500 MΩ in one hour after the processing. It has recovered and maintains a high resistance value thereafter. Therefore, it can be determined that sufficient insulation has been recovered in one hour after the treatment.

  On the other hand, as in FIG. 5A, the to-be-processed terminal block 16.2 processed according to the conventional insulation recovery method has a resistance value of less than 1 MΩ even after 3.5 hours of processing. And the to-be-processed terminal block 16.2 was able to exceed the resistance value of 100 M (ohm) 7.5 hours after a process.

  As in FIG. 5A, based on the time when the resistance value exceeds 100 MΩ, the insulation recovery method according to the present invention is 7.5 times faster than the conventional insulation recovery method. Insulation recovery can be realized.

FIG. 6 is a diagram showing the insulation recovery characteristics after the treatment when the immersion time is 5 minutes.
Fig.6 (a) is a resistance value between grounds (the average of the resistance value between the terminal of each phase, and ground).

  FIG. 6B shows interphase resistance values (average of resistance values between ab phase, bc phase, and ca phase).

  Referring to FIG. 6 (a), the terminal block 16.1 processed according to the insulation recovery method according to the present invention recovered to a resistance value of about 500 MΩ in 1 hour after the treatment, and sufficient insulation recovery was achieved. Can be determined. Then, at 3.5 hours after the treatment, the resistance value has recovered to 1000 MΩ, which is the maximum value that can be measured by the insulation resistance meter 20.

  On the other hand, the to-be-processed terminal block 16.2 processed according to the conventional insulation recovery method has a resistance value of less than 100 MΩ even 2.5 hours after the processing. And the to-be-processed terminal block 16.2 was able to exceed the resistance value of 100 M (ohm) 3.5 hours after a process.

  As described above, based on the time when the resistance value exceeds 100 MΩ, the insulation recovery method according to the present invention achieves insulation recovery at a speed 3.5 times faster than the conventional insulation recovery method. it can.

  Referring to FIG. 6B, the terminal block 16.1 processed according to the insulation recovery method according to the present invention recovered the resistance value to about 1000 MΩ in 1 hour after the processing, and the value thereafter. To maintain. Therefore, it can be determined that sufficient insulation has been recovered in one hour after the treatment.

  On the other hand, as in FIG. 6A, the to-be-processed terminal block 16.2 processed according to the conventional insulation recovery method has a resistance value of less than 100 MΩ even after 2.5 hours from the processing. And the to-be-processed terminal block 16.2 was able to exceed the resistance value of 100 M (ohm) 3.5 hours after a process.

  As in FIG. 6A, based on the time when the resistance value exceeds 100 MΩ, the insulation recovery method according to the present invention is 3.5 times faster than the conventional insulation recovery method. Insulation recovery can be realized.

  As described above, the insulation recovery method according to the present invention can recover sufficient insulation within one hour regardless of the time of immersion in seawater. Further, the recovery time can be greatly shortened as compared with the insulation recovery process by conventional water cleaning.

  Next, a comparative study was conducted on changes in insulation characteristics due to humidity after insulation recovery treatment. In general, when a fouling substance adhering to the surface of an insulator absorbs moisture due to humidity, the leakage current increases and the insulation characteristics deteriorate. That is, if the resistance value fluctuates due to the influence of humidity, it means that the contaminated material has not been sufficiently cleaned.

  FIG. 7 is a diagram showing the relationship between the humidity after the treatment and the resistance to ground when the immersion time is 1 hour. Moreover, FIG. 8 is a figure which shows the relationship between the humidity after a process in case immersion time is 1 hour, and an interphase resistance value.

FIGS. 7A and 8A show the case of the insulation recovery method according to the present invention.
FIG. 7B and FIG. 8B show the case of the conventional insulation recovery method.

  Referring to FIGS. 7A and 8A, according to the insulation recovery method of the present invention, the resistance value is maintained at about 1000 MΩ at medium humidity (about 40% to about 70%). . Further, even when the humidity is increased (about 70% or more), the resistance value decreases to about several tens of MΩ, but it is within a practically allowable range, and it can be said that a necessary cleaning effect is obtained.

  On the other hand, referring to FIGS. 7B and 8B, according to the conventional insulation recovery method, the resistance value is maintained at about 1000 MΩ at medium humidity (about 40% to about 70%). However, when the humidity is increased (about 70% or more), the resistance value is reduced to less than 1 MΩ. That is, according to the conventional insulation recovery method, it can be determined that the amount of the remaining fouling material is large and the moisture absorption region is generated. Therefore, according to the conventional insulation recovery method, it can be determined that the necessary cleaning effect is not obtained and sufficient insulation recovery is not performed.

  FIG. 9 is a diagram showing the relationship between the humidity after treatment and the resistance to ground when the immersion time is 5 minutes. Moreover, FIG. 10 is a figure which shows the relationship between the humidity after a process and the interphase resistance value when immersion time is 5 minutes.

FIG. 9A and FIG. 10A show the case of the insulation recovery method according to the present invention.
FIG. 9B and FIG. 10B show the case of the conventional insulation recovery method.

  Referring to FIGS. 9A and 10A, according to the insulation recovery method according to the present invention, as in FIGS. 7A and 8A described above, medium humidity (about 40%) is obtained. (About 70%), the resistance value is maintained at about 1000 MΩ. Further, even when the humidity is increased (about 70% or more), the resistance value decreases to about 10 MΩ, but it is within a practically allowable range, and it can be said that a necessary cleaning effect is obtained.

  On the other hand, referring to FIGS. 9B and 10B, according to the conventional insulation recovery method, the resistance value is maintained at about 1000 MΩ at medium humidity (about 40% to about 70%). However, when the humidity is increased (about 70% or more), the resistance value is reduced to less than 1 MΩ. Therefore, according to the conventional insulation recovery method, it can be determined that the necessary cleaning effect is not obtained and sufficient insulation recovery is not performed.

  As described above, the insulation recovery method according to the present invention is less susceptible to the influence of humidity after processing, and can maintain the recovered insulation characteristics. That is, since the deterioration of the insulation characteristics due to moisture absorption of the fouling material has not occurred, it can be determined that the fouling material has been sufficiently washed to restore insulation.

  In the above description, the case where the object to be recovered from insulation is a terminal block has been described, but it goes without saying that the present invention can also be applied to other electric devices and parts thereof.

  According to the embodiment of the present invention, compared with the conventional insulation recovery method, it is possible to achieve a much quicker insulation recovery, and it is possible to suppress residual contaminants due to its high cleaning effect. Insulation is not reduced again due to moisture absorption. Accordingly, it is possible to realize an insulation recovery method that quickly recovers insulation when insulation is reduced due to contamination of the insulator.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is an external view of the terminal block which is an example of the application object of the insulation recovery method which concerns on this invention. It is a figure which shows the processing flow of the insulation recovery method which concerns on this invention. It is a figure which shows the outline | summary of a process of the insulation recovery method which concerns on this invention. It is a schematic block diagram of the verification apparatus for verifying the effect of the cleaning agent which concerns on this invention. It is a figure which shows the insulation recovery characteristic after a process in case the immersion time is 1 hour. It is a figure which shows the insulation recovery characteristic after a process in case immersion time is 5 minutes. It is a figure which shows the relationship between the humidity after a process at the time of immersion time being 1 hour, and resistance value between ground. It is a figure which shows the relationship between the humidity after a process when immersion time is 1 hour, and an interphase resistance value. It is a figure which shows the relationship between the humidity after a process in case immersion time is 5 minutes, and the resistance value between ground. It is a figure which shows the relationship between the humidity after a process in case immersion time is 5 minutes, and an interphase resistance value.

Explanation of symbols

  1 Terminal block, 2a, 2b, 2c Conductor plate, 4.1a, 4.2a, 4.1b, 4.2b, 4.1c, 4.2c Clamping screw, 6 Insulation base, 8 Insulation partition, 10 Verification device, 12.1, 12.2 Simulated electrical circuit, 14.1, 14.2 Cable, 15, 17 Support rail, 16.1, 16.2 Processed terminal block, 18.1, 18.2 Measurement terminal block, 19 Short-circuit cable, 20 Insulation resistance meter, 22 Water tank, 30 Spray can, 32 Brush, 34 West, GND Ground potential.

Claims (3)

In an electrical apparatus including a plurality of current-carrying parts insulated from each other through an insulator, an insulation recovery method when the insulator is soiled,
Cleaning the fouling material adhering to the insulator by spraying a cleaning agent;
The cleaning agent is
55-65 wt% isohexane,
5-10 mass% ethanol,
1-5 mass% n-hexane,
An insulation recovery method comprising 1 to 5% by mass of acetone.   The insulation recovery method according to claim 1, wherein the cleaning step includes a step of brushing the insulator so as to separate the fouling material from the insulator.   The insulation recovery method according to claim 1, further comprising a step of wiping off the remaining cleaning agent after the cleaning step is completed.

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