JP2023082726A - Insulation quality confirmation method for insulation rope and insulation quality confirmation device used therefor - Google Patents

Abstract

To provide an insulation quality confirmation method and an insulation quality confirmation device that can accurately determine a section of an insulation defect of an insulation rope.SOLUTION: While an insulation rope R having an insulation layer Ro at an outer periphery of a rope core Rc is moved between a voltage application electrode 10c and a detection electrode 20, an inspection voltage which is low in level enough not to cause a dielectric breakdown is continuously applied to the voltage application electrode 10, and the detection electrode 20 measures a leakage current IL1 flowing on an outer surface of the insulation rope R and a leakage current IL2 flowing in the rope core Rc of the insulation rope R. It is determined that the insulation rope R is (a) an acceptable product satisfying insulation quality when only the leakage current IL1 flow on the outer surface of the insulation rope R or (b) an unacceptable product which does not satisfy the insulation quality when the leakage current IL2 flows in the rope core Rc in addition to the leakage current IL1 flowing on the outer surface of the insulation rope R.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an insulation confirmation method for confirming the insulation performance of an insulated rope and making pass/fail judgments, and an insulation confirmation device used therefor.

Insulated ropes are used to support wires to be replaced while keeping nearby power lines live in the replacement work of transmission lines.
Insulated ropes are required to have high insulation properties because they may come into contact with live wires or be exposed to induced voltage. Therefore, the insulated rope is composed of a rope core made of braided non-conductive or insulating fibers and an insulating layer in which the outer periphery of the rope core is coated with an insulating resin. The insulating layer itself has insulating performance and waterproof performance to prevent rainwater from entering the rope core. For this reason, the infiltration of rainwater into the rope core of the insulated rope is suppressed, and the flow of electricity due to the wetting of the rope core is also prevented. Therefore, the live line can be supported by the insulated rope without any trouble when the transmission line is rewired.

However, if the insulation layer of the insulated rope is damaged, rainwater will enter the core of the rope from there, resulting in loss of insulation. Scratches in the insulating layer are caused not only by manufacturing defects but also during use after manufacturing.
Therefore, in order to ensure the safety of transmission line replacement work, it is necessary to check the insulation properties of the insulated rope, and for that purpose, a highly reliable insulation confirmation test is required. In addition, this insulation confirmation test is required both immediately after manufacturing and each time the product is used after manufacturing.

By the way, there is an insulating rod as a tool used at the same work site as the insulating rope. Insulating rods are also stipulated by law to undergo an insulation test from the viewpoint of ensuring safety.
The test method (hereinafter referred to as prior art 1) is to apply an alternating voltage twice the voltage applied to the live line between two points on an insulating rod of a predetermined length and confirm that it can withstand for 5 minutes. is. In addition, several tens of centimeters of the entire length of the insulating rod were separated, and the test was performed sequentially on each part.

In some cases, the test of the insulated rope is performed according to the prior art 1 described above.
However, according to the prior art 1, the test is an intermittent method in which the test is performed by moving several tens of centimeters after the application of electricity for 5 minutes.

Regarding the intermittent and inefficient test of the prior art 1, a technique has been proposed that enables continuous testing (hereinafter referred to as prior art 2, see Patent Document 1).
This prior art 2 is configured as follows. A predetermined position of the insulated filament is sandwiched between a pair of electrifying rollers, and a portion to which a voltage is applied by the pair of electrifying rollers is defined as an electrifying portion, and at least one of the front and rear portions of the electrifying portion is positioned at a predetermined distance. is sandwiched between a pair of current detection rollers, and a portion that measures the current flowing through the pair of current detection rollers serves as a current pick-up portion. An ammeter is interposed in the current pick-up section, and measures the magnitude of the current flowing through the insulated wire between the applying section and the current pick-up section.

In this prior art 2, an AC voltage from an AC power source is applied to the application roller while moving the insulating wire, and a weak current transmitted through the insulating wire is detected by an ammeter connected to the current detection roller. It is described that the withstand voltage characteristic can be tested by measuring.

However, the conventional technique 2 has the following problems.
(1) Patent Literature 1 describes that a predetermined voltage is applied to the applying portion (paragraph 0080) and that a weak current flows through the insulating wire (paragraph 0084). No specific technical information is described at all.
Therefore, inferring from the description that a weak current flows through the insulated filamentary material, it is understood that if the inside of the insulated filamentous material is wet, even a weak current will flow, but if it is dry, it will not flow. It seems that they are aware that the withstand voltage test can be performed in addition to the However, in actuality, when the inside of the insulating wire is wet, the insulating resin breaks down in the thickness direction between the electrode and the wet core material, and holes are formed in the resin, making the inside conductive. There is a risk of a short circuit through the rope, causing an abnormally large current to flow and burning the rope. In addition, if dielectric breakdown occurs, even if it is known that there is a wetted portion in the insulating wire between the applying portion and the current pick-up portion, it is impossible to specifically and accurately identify the location of the wetted portion. Can not. In other words, there is a problem of lack of position specifying ability.
(2) Furthermore, in the prior art 2, there is a problem that an error due to static induction current cannot be avoided. That is, the statically induced current that flows through the current pick-up section through the static capacitance in the air between the applying section and the current pick-up section flows to the ammeter via the current detection roller. This electrostatic induction current increases in proportion to the magnitude of the applied voltage, and may reach several tens of μA. When this induced current is added to the current flowing through the insulated rope R that you want to actually measure, the total current contains noise (the induced current) that is not useful for pass/fail judgment. was gone.

Japanese Unexamined Patent Application Publication No. 2004-20252

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an insulation confirmation method and an insulation confirmation device capable of accurately determining an insulation failure section in an insulated rope.

A method for checking the insulation of an insulated rope of the first invention is a method for checking the insulation of an insulated rope having a rope core braided with non-conductive fibers and an insulating layer in which the outer periphery of the rope core is coated with an insulating resin, A charging electrode for applying a voltage to the insulating rope, a detecting electrode for measuring the leakage current flowing through the insulating rope, an ammeter for measuring the current flowing through the detecting electrode, and a ground in the space surrounding the detecting electrode. Using an insulation rope insulation confirmation device consisting of an electrostatic shield box connected to the insulation layer, while moving the insulation rope between the application electrode and the detection electrode, the insulation layer on the application electrode A test voltage of a level that does not cause insulation breakdown is continuously applied to the detection electrode, and the leakage current flowing through the outer surface of the insulating rope and the leakage current flowing through the rope core of the insulating rope are measured with the detection electrode. When the measured value is (a) only the leakage current flowing on the outer surface of the insulated rope, the insulated rope is judged to be an acceptable product that satisfies the insulation, and (b) the leakage current flowing on the outer surface of the insulated rope is In addition, when the leakage current flowing through the rope core is also included, the insulated rope is judged as a rejected product that does not satisfy insulation.
A method for checking the insulation of an insulated rope according to a second invention is characterized in that, in the first invention, when the measured value of the leakage current starts to rise, it is determined that the wet section of the insulated rope begins, and at the same time the applied voltage is set to the inspection start voltage. to a lower test continuation voltage, and the test continuation voltage is applied until it can be determined that the wet section of the insulating rope has ended.
A device for checking the insulation of an insulated rope according to a third aspect of the invention is a device for checking the insulation of an insulated rope used in the method for checking the insulation of an insulated rope according to claim 1, comprising: a charging electrode for applying a voltage to the insulated rope; A detection electrode for measuring leakage current flowing through an insulating rope, an ammeter for measuring current flowing through the detection electrode, and an electrostatic shield box installed in the space surrounding the detection electrode and grounded. characterized by

According to the 1st invention, there exist the following effects.
a) There is a large difference in the amount of leakage current that flows through the outer surface of the insulated rope when the insulation is good, and the leakage current that flows through the core of the insulated rope when the insulation is poor. Since the determination can be made accurately and the amount of current changes rapidly, the location of the insulation failure can be specified accurately.
b) Since the statically induced current flowing in the air between the energizing electrode and the detecting electrode flows from the electrostatic shield box to the ground, in the ammeter there is only leakage current flowing to the detecting electrode. For this reason, it is possible to accurately judge the insulating property based on the amount of leakage current as a judgment criterion.
According to the second invention, when moisture in the insulating rope is confirmed during the insulation inspection under the application of the inspection start voltage, the voltage is switched to the inspection continuation voltage lower than the inspection start voltage, so that during the inspection Dielectric breakdown is less likely to occur. Therefore, the insulated rope can be inspected without being damaged.
According to the third aspect of the invention, the electrostatic induction current flowing in the air between the charging electrode and the detection electrode flows from the electrostatic shield box to the ground. For this reason, it is possible to accurately judge the insulating property based on the amount of leakage current as a judgment criterion.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the insulation confirmation method and insulation confirmation apparatus which concern on this invention. FIG. 2 is an enlarged view of a main part of the insulation checking device shown in FIG. 1; FIG. 3 is an explanatory diagram of the insulation confirmation device shown in FIG. 2, (A) is a configuration diagram of an electrode, and (B) is a configuration diagram of a shield box. (A) is an explanatory diagram of leakage current and measured current in the insulation confirmation device of the present invention, and (B) is an explanatory diagram of measured current in the prior art. FIG. 4 is an explanatory diagram of leakage current during a continuous test of the insulated rope in the insulation confirmation method of the present invention; FIG. 4 is an explanatory diagram of measured current in the insulation confirmation method of the present invention; It is explanatory drawing of an example of the insulation confirmation method in this invention.

Next, embodiments of the present invention will be described with reference to the drawings.
An object whose insulating properties can be tested by the present invention is an insulating rope consisting of a rope core braided with non-conductive fibers and an insulating layer coated with an insulating resin on the outer periphery of the rope core. In this specification, the term "non-conductive fibers" is used to include insulating fibers. If the rope has this structure, even if there are various kinds of fibers in the rope core and various braiding methods, various kinds of insulating resins, and even if additional insulating materials are used, Application of the present invention is possible.

Since the rope core of the insulated rope is made of non-conductive fibers, it normally has no conductivity, but when rainwater enters and the rope core becomes wet, the conductivity suddenly increases. The insulation layer functions to prevent rainwater from entering the inside of the rope core. It will damage the insulation of the rope. Also, if the rope core is not sufficiently dried at the time of manufacture, the insulation will be lost.

FIG. 1 shows an insulation confirmation method according to the present invention and an insulation confirmation device used therefor.
An insulating rope R is unwound from an unwinding roll 1, wound on a winding roll 2, and moved in the direction of arrow a.
A pair of electrodes 10 and 20 constituting the insulation confirmation device A are installed between the unwinding roll 1 and the winding roll 2 . The pair of electrodes 10 and 20 are mounted on a portable frame, but it is optional whether they are portable or stationary.
The driving of the unwinding roll 1 and the winding roll 2 and the driving of the electrodes 10 and 20 are performed from the cab 3 .

As shown in FIG. 2, of the pair of electrodes 10 and 20, one electrode 10 is a charging electrode and the other electrode 20 is a detection electrode. The energizing electrode 10 receives a voltage from the power source 4 via the electric wire 5 and energizes the insulated rope R. As shown in FIG. The detection electrode 20 is an electrode for detecting a current flowing through the insulating rope R, is connected to a ground wire 31 , and an ammeter 32 is interposed in the ground wire 31 .

Details of the charging electrode 10 will be described with reference to FIGS. 2 and 3A.
The energizing electrode 10 has a pair of rollers 11 and 12, and is arranged so as to sandwich the insulating rope R from above and below. The lower roller 11 is pivotally supported by a fixed frame 13 . The upper roller 12 is pivotally supported by the movable frame 14 . The roller 12 is pulled downward by a spring 15 so that the pair of rollers 11 and 12 are in firm contact with the outer peripheral surface of the insulating rope R. Therefore, the insulating rope R can be moved in the direction of the arrow a by applying a rotational driving force to the pair of rollers 11 and 12 to rotate them. Moreover, if the movable frame 14 is energized, it is possible to energize the insulated rope R that is moving through the rollers 12 . This energizing electrode 10 is installed on an insulating base 35 as a unit. The insulating base 35 is a base made of an insulating material.

Details of the detection electrode 20 will be described with reference to FIGS. 2 and 3B.
The detection electrode 20 has a pair of rollers 21 and 22, and is arranged so as to sandwich the insulating rope R from above and below. The lower roller 21 is pivotally supported by a fixed frame 23 . The upper roller 22 is pivotally supported by a movable frame 24 . The roller 22 is pulled downward by a spring 25, and the pair of rollers 21 and 22 firmly contact the outer peripheral surface of the insulating rope R. Therefore, the insulating rope R can be moved in the direction of the arrow a by applying a rotational driving force to the pair of rollers 21 and 22 to rotate them. Also, the current that has flowed through the insulating rope R flows through the fixed frame 23 .
This detection electrode 20 is installed on an insulating base 35 as a unit.

A ground wire 31 is connected to the fixed frame 23 of the detection electrode 20 , and an ammeter 32 is interposed in the ground wire 31 . The fixed frame 23 is insulated from the ground and a shield box 30 to be described later by an insulating base 35 .
Therefore, all currents flowing through the insulating rope R can be measured by the ammeter 32 .

A shield box 30 is installed around the detection electrode 20 . The shield box 30 is a rectangular parallelepiped box made of conductive material. Examples of the conductor material that can be used include metals such as iron and aluminum, carbon fibers other than metals, and the like, but any material can be used without particular limitation as long as it has conductivity. The shield box 30 may be composed of a flat plate, or may be a perforated plate obtained by perforating a flat plate.

The shield box 30 is a box that surrounds the detection electrode 20 and the insulating base 35, and is open only on the entry side and the exit side of the insulation rope R. is configured to cover the
A ground wire 34 is connected to the shield box 30 .

As shown in FIG. 4(A), in the apparatus of this embodiment, the static induced current is caused mainly through the static capacitance in the air between the charging electrode 10 and the shield box 30 installed around the detection electrode 20. Ic flows. Since the electrostatically induced current Ic flows through the shield box 30 to the ground wire 34, the detection electrode 20 can be protected from electrostatic induction.
Therefore, the ammeter 32 connected to the detection electrode 20 can measure only the current amount of the leakage current IL transmitted through the insulating rope R.

For comparison, the electrostatic induced current Ic in the prior art, which does not have a shield box as in Patent Document 1, will be described with reference to FIG. 4(B).
Since the detection electrode 20 is not provided with the shield box 30 in the prior art, the electrostatic induced current Ic mainly flowing through the capacitance in the air between the charging electrode 10 and the detection electrode 20 passes through the detection electrode 20 to the ammeter 32 . flow to In this case, the leakage current IL that has propagated through the insulating rope R in the direction from the charging electrode 10 to the detection electrode 20 also flows to the ammeter 32 . Therefore, the amount of current that can be measured by the ammeter 32 is the sum of the leakage current IL and the electrostatic induction current Ic, and the leakage current IL necessary for determining the insulation properties of the insulating rope R cannot be accurately measured. There is a problem.

Compared with the problem of the prior art, the present invention shown in FIG. can be accurately determined.

Next, a method for using the insulation confirmation device of the present invention will be described.
An insulated rope R is set in the insulation confirmation device A shown in FIGS. Specifically, the insulating rope R unwound from the unwinding roll 1 is passed between the pair of rollers 11 and 12 of the applying electrode 10 and between the pair of rollers 21 and 22 of the detecting electrode 20, and further the insulating rope R is wound around the take-up roll 2. After that, the winding roll 2, the unwinding roll 1, the applying electrode 10 and the detection electrode 20 are driven to move the insulating rope R in the direction of the arrow a. By doing this, the preparation for the continuous inspection is completed.

The insulation confirmation method according to the present invention is as follows.
As shown in FIGS. 1 and 2, while moving the insulating rope R between the charging electrode 10 and the detecting electrode 20, the charging electrode 10 is applied with an inspection voltage of a level that does not cause dielectric breakdown in the insulating layer. Apply electricity continuously. Then, the leakage current IL is measured as shown in FIG. 4(A). The term "leakage current IL" as used herein means "current flowing through the surface or inside of an insulating material" as defined in JIS standard [T1011].
The "current flowing through the surface of the insulating material" in the above definition corresponds to the leakage current _IL1 flowing through the outer surface of the insulating rope R herein, and the "current flowing through the interior of the insulating material" in the present invention. Corresponds to the leakage current _IL2 flowing inside the insulating rope R, ie through the rope core Rc.
Therefore, the detection electrode 20 measures the leak current IL ₁ flowing through the outer surface of the insulating rope R and the leak current IL ₂ flowing through the core of the insulating rope R shown in FIG. 5(A).

In FIGS. 5A and 5B, reference character R indicates an insulating rope composed of a rope core Rc and an outer insulating layer Ro. In FIG. 5, the insulating rope R is shown in cross section, and the insulating layer Ro is hatched with dotted lines. As shown in the figure, the outer periphery of the rope core Rc is entirely covered with an insulating layer Ro both in the circumferential and longitudinal directions. Therefore, as long as the insulating layer Ro is normal, the rope core Rc is dry. I have something to do. In this specification, a section where the rope core Rc is wet (a section in the longitudinal direction of the insulating rope R) is referred to as a wet section.

As shown in FIG. 4(A), when an insulated rope R is sandwiched at two points between a charging electrode 10 and a detecting electrode 20 and an AC voltage is applied, a leakage current IL flows through a place or route where it should not normally flow. That is, the leakage current IL appears as a leakage current _IL1 flowing through the outer surface of the insulating layer Ro of the insulating rope R, or as a leakage current _IL2 flowing inside the non-conductive rope core Rc of the insulating rope R.

When the insulating rope R is dry, as shown in FIG. 5B, only the leakage current _IL1 flows through the outer surface of the insulating layer Ro when the insulating rope R is sandwiched between the charging electrode 10 and the detection electrode 20. However, as shown in FIG. 6, the amount of leakage current _IL1 that flows during drying is proportional to the applied voltage, but is very small.
On the other hand, when the rope core Rc of the insulating rope R becomes wet, the rope core Rc becomes conductive. In this case, as shown in FIG. 5A, on the side of the charging electrode 10, the insulating layer Ro is sandwiched between the charging electrode 10 and the conductive rope core Rc, and a capacitor C is formed here. . Also, it is considered that a capacitor C is similarly formed on the detection electrode 20 side. These two capacitors and the rope core Rc, which has become conductive due to wetting, form a series circuit through which leakage current _IL2 flows. As shown in FIG. 6, when wet, this causes a very small amount of IL ₁ to flow in addition to this leakage current IL ₂ , and tends to significantly increase the amount of current as the applied voltage increases.

The formation phenomenon of the capacitor C referred to here was discovered by the present inventor for the first time, and through experiments described later, the leakage current value (IL ₁ +IL ₂ ) flowing through the rope core Rc when wet and the applied voltage are shown in FIG. The theoretical background is the recognition that a substantially proportional relationship holds as shown in Fig. 6.

Advantages of the insulation confirmation method of the present invention will be described with reference to FIG.
An inspection voltage is applied to the applied electrode 10 from the power supply 4 . Then, if the insulation layer Ro of the insulation rope R has a defect such as a tear or a hole, rainwater enters the rope core Rc and becomes wet and conductive, so as shown in FIG. A large current, which is the current _IL1 plus the leakage current _IL2, flows.
On the other hand, when there is no defect in the insulating layer Ro of the insulating rope R, the rope core Rc is dry, so only the leakage current _IL1 flows as shown in FIG. 5(B).

As shown in FIG. 6, there is a significant difference between the total amount of leakage currents IL ₁ and IL ₂ and the amount of leakage current IL ₁ only. Judgments can be made accurately. Moreover, since the rise of the current amount is steep, the start position of the wet section (that is, the section with poor insulation) can also be specified accurately and concretely, for example, in units of cm. In addition, since the amount of current drops sharply at the end point of the wet section, it can be specified accurately in units of cm.

In the present invention, the main purpose of the inspection is the presence or absence of the wet section of the rope core Rc, in other words, the quality of the insulation, so the applied voltage may be somewhat low. Specifically, it may be about 20 kV. In addition, instead of applying to a fixed point for a long period of time (for example, about several minutes), a current of about 50 kV may be applied as long as the current is applied while changing the application location continuously and the current increase can be interrupted instantaneously. . In any case, a voltage of a level that does not cause dielectric breakdown and damage to the insulating layer Ro of the insulating rope R can be used. In this specification, this level of voltage is used as the test voltage.

Next, an experimental example shown in FIG. 7 will be used to explain how the insulation confirmation test is continuously performed over the entire length of the insulated rope R. FIG. The apparatus shown in FIG. 1 was used for the experiment.
In FIG. 7, the lower horizontal axis indicates the inspection position of the insulating rope R, and the upper horizontal axis indicates the damaged portion (that is, the wet section of the rope core Rc) in the insulating rope R to be inspected in black. there is That is, the insulating rope R used in the experiment was soaked in water for 24 hours by damaging the insulating layer Ro at positions of 150 cm, 220 cm and 240 cm shown on the upper horizontal axis of FIG. I used the one with the interval.

In the experimental example of FIG. 7, two types of test voltages, namely, test start voltage and test continuation voltage, are used. The test start voltage was set to 50 kV, and the test continuation voltage was set to 20 kV. The reason why the test start voltage is set at 50 kV and is higher than the test continuation voltage is that when the voltage is high, the wet section approaches and the amount of leakage current begins to increase, and the rise of the amount of current on the ammeter can be clearly and quickly grasped. .
Also, the reason why the test continuation voltage is set to 20 kV and is lower than the test start voltage is to prevent dielectric breakdown from occurring in the insulated rope R even if the voltage is applied for a long period of time.

Experiments were conducted as follows.
First, an inspection start voltage of 50 kV is applied to the charging electrode 10, and the unwinding roll 1, the rollers 11 and 12 of the charging electrode 10, the rollers 21 and 22 of the detection electrode 20, and the winding roll 2 are rotationally driven to insulate. Rope R was moved. At this time, the insulating rope R moves from 0 cm (left end on the upper horizontal axis) to 350 cm (right end on the upper horizontal axis) shown on the upper horizontal axis of FIG. Then, when a portion whose insulation is desired to be checked in the longitudinal direction of the insulating rope R (hereinafter sometimes referred to as a position to be inspected) comes between the charging electrode 10 and the detection electrode 20, the leakage current IL flowing in that section is detected. can do.
After the start of the experiment, when the inspection target position of the insulating rope R reached around 100 cm, the measured value of the leakage current IL began to rise. From this current increase, it can be judged that the wet section of the insulating rope R begins. Therefore, if the voltage is applied in this state, dielectric breakdown occurs. Therefore, the voltage applied was lowered from the inspection start voltage of 50 kV to a lower inspection continuation voltage of 20 kV, and the inspection was continued. Then, the test continuation voltage was applied until it was determined that the wet section of the insulating rope R was finished.

At positions of 150 cm, 220 cm and 240 cm where wet sections were created in the insulating rope R, the amount of leakage current IL measurable by the ammeter 32 increased. The leakage current IL increased because the leakage current _IL2 flowing inside the rope core Rc was added to the leakage current _IL1 flowing through the outer surface of the insulating layer Ro. Moreover, the leakage current IL rises sharply and increases proportionally. Also, the decrease in the amount of leakage current is abruptly reduced.
As described above, the increase and decrease in the leakage current IL appear instantaneously, indicating that the start and end of the wet section can be identified accurately.
Moreover, since the inspection continuation voltage of 20 kV is lower than the inspection start voltage of 50 kV, it is easy to handle and can be carried out safely.

INDUSTRIAL APPLICABILITY The insulation property checking method and insulation property checking device of the present invention can be used to check the insulation performance of an insulated rope immediately after manufacture, as well as to check whether or not the insulation performance of an insulated rope during use has deteriorated.

1 unwinding roll 2 winding roll 10 electrifying electrode 11 roller 12 roller 20 detection electrode 21 roller 22 roller 30 shield box 32 ammeter Ic electrostatic induction current IL leakage current A insulation confirmation device

Claims (3)

A method for checking insulation of an insulating rope having a rope core braided with non-conductive fibers and an insulating layer in which the outer periphery of the rope core is coated with an insulating resin,
A charging electrode for applying a voltage to the insulating rope, a detecting electrode for measuring the leakage current flowing through the insulating rope, an ammeter for measuring the current flowing through the detecting electrode, and a ground in the space surrounding the detecting electrode. Using an insulation rope insulation confirmation device consisting of an electrostatic shield box connected to
While moving the insulating rope between the applying electrode and the detecting electrode,
continuously applying an inspection voltage at a level that does not cause dielectric breakdown to the insulating layer to the applied electrode;
The detection electrode measures the leakage current flowing through the outer surface of the insulating rope and the leakage current flowing through the rope core of the insulating rope,
The measured value of the leakage current is
(a) judging that the insulated rope is an acceptable product that satisfies the insulation properties when only the leakage current flows through the outer surface of the insulated rope;
(b) Insulation check of an insulated rope, characterized in that the insulated rope is judged as a rejected product that does not satisfy the insulation when the leakage current flowing through the core of the insulated rope is included in addition to the leakage current flowing through the outer surface of the insulated rope. Method. When the measured value of the leakage current starts to rise, it is determined that the wet section of the insulating rope begins, and at the same time, the applied voltage is decreased from the test start voltage to a lower test continuation voltage, and the wet section of the insulating rope ends. 2. The method for checking the insulation of an insulated rope according to claim 1, wherein the test continuation voltage is applied until it can be determined that An insulation confirmation device for an insulated rope used in the insulation confirmation method for an insulated rope according to claim 1,
a energizing electrode for applying a voltage to the insulated rope;
a detection electrode for measuring leakage current flowing through the insulating rope;
an ammeter that measures the current flowing through the detection electrode;
An apparatus for checking the insulation of an insulating rope, comprising an electrostatic shield box installed in the space surrounding the detection electrode and connected to the ground.

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