JP2003234224A - Method of arranging conductor with respect to zero- phase current transformer and holding and position adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the conventional problem that the detection of leakage currents at the level that becomes necessary for diagnosing insulation deterioration is not made with accuracy. <P>SOLUTION: A method of arranging conductor with respect to a zero-phase current transformer includes a step of arranging a plurality of conductors 2 passed through a zero-phase current transformer 3 along the diametral line of the through section of the transformer 3, and a step of observing the currents flowing to the conductors 2 by means of an measuring instrument 4 and rotating the conductors 2 or transformer 3 to the positions where the observed current values become the minimum. A conductor holding and position adjusting device for the zero-phase current transformer 3 is provided with a plurality of conductors which are passed through the through section of the transformer 3 and arranged along the diametral line of the through section and means which fix the conductors and current transformer. Consequently, detection accuracy can be obtained for leakage currents in very small areas. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor arranging method and a holding / position adjusting device for a zero-phase current transformer used in a leakage current detecting method which is one of methods for diagnosing insulation deterioration of cables. In particular, the present invention relates to a conductor arrangement method and a holding / position adjusting device for a zero-phase current transformer having improved balance characteristics.

[0002]

2. Description of the Related Art A conventional conductor arranging method for a zero-phase current transformer will be described with reference to the drawings. FIG. 5: is a figure which shows the installation place of a zero phase current transformer.

In FIG. 5, 1 is a load such as a motor (M), 2 is a system wire for supplying electric power to the load 1, and 3 is a zero-phase current transformer for detecting a zero-phase current flowing in the system wire 2. (ZCT) 4 is a measuring instrument such as an ammeter for observing the zero-phase current detected by the zero-phase current transformer 3.

FIG. 6 is a diagram showing a schematic cross section of the zero-phase current transformer portion of FIG.

FIG. 6 shows a position where the system electric wire 2 penetrates the zero-phase current transformer 3. Since the zero-phase current transformer 3 has a balanced characteristic, a zero-phase current is observed when a balanced current is passed through the system wire 2. Therefore, the zero-phase current transformer 3 is shielded, and the system electric wire 2 penetrating the zero-phase current transformer 3 is passed near the center to improve the equilibrium characteristics.

The zero-phase current is measured by using the zero-phase current transformer 3, as shown in FIG. As shown in FIG. 6, three-phase system electric wires 2 (wiring) are arranged in the center of the zero-phase current transformer 3. However, since the zero-phase current transformer 3 has the equilibrium characteristic, even if the sum of the currents passing through the zero-phase current transformer 3 is zero, a large current flows through the primary wiring, so that the current flows to the secondary side. An electric current flows. Therefore, if you want to detect a small zero-phase current,
The equilibrium property determines the measurement limit.

Although the zero-phase current increases with the progress of deterioration, it is difficult to measure the zero-phase current in a minute area due to the detection error due to the equilibrium characteristic.

[0008]

In the conventional conductor arranging method for the zero-phase current transformer as described above, since the zero-phase current transformer has the equilibrium characteristic, the level required for diagnosing insulation deterioration is required. However, there is a problem that the leakage current cannot be accurately detected.

The present invention has been made to solve the above-mentioned problems, and can improve the equilibrium characteristics,
An object of the present invention is to obtain a conductor arrangement method and a holding / position adjusting device for a zero-phase current transformer capable of measuring a zero-phase current in a minute region.

[0010]

A conductor arranging method for a zero-phase current transformer according to the present invention comprises a step of linearly arranging a plurality of conductors penetrating the zero-phase current transformer on the diameter of the penetrating portion. A step of observing a current flowing through the conductor with a measuring instrument and rotating the plurality of conductors or the zero-phase current transformer to a position where the observed value is a minimum, the zero-phase current transformer and the plurality of zero-phase current transformers. Fixing the conductor of the book.

Further, according to the method of arranging the conductors for the zero-phase current transformer according to the present invention, there is provided a first line parallel to the connecting line to the measuring instrument and passing through the center of the zero-phase current transformer, and the plurality of conductors. And the second conductor passing through the center of the zero-phase current transformer and the second line passing through the center of the zero-phase current transformer are fixed at a position of 90 degrees.

The holding / position adjusting device according to the present invention penetrates the zero-phase current transformer and the penetrating portion of the zero-phase current transformer, and a plurality of linearly arranged on the diameter of the penetrating portion. A conductor, and a means for fixing the plurality of conductors and the zero-phase current transformer are provided.

Further, the holding / position adjusting device according to the present invention includes a first line which is parallel to the connecting line to the measuring instrument and which passes through the center of the zero-phase current transformer, and which passes through the centers of the plurality of conductors. The angle with the second line passing through the center of the zero-phase current transformer is 90 degrees.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. A conductor placement method and a holding / position adjusting device for a zero-phase current transformer according to Embodiment 1 of the present invention will be described with reference to the drawings. 1 is a diagram showing a method of arranging conductors in a zero-phase current transformer according to Embodiment 1 of the present invention. In each figure, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, in the first embodiment, the conductor (system electric wire 2) penetrating the zero-phase current transformer 3 is arranged linearly on the diameter, and the zero-phase current transformer 3 and the linear shape are arranged linearly. The problems described above are solved by rotating the zero-phase current transformer 3 or the conductor 2 to adjust the positions of the three conductors 2 arranged in 1 above, and fixing them at positions with good balance characteristics.

The zero-phase current transformer 3 according to the first embodiment improves the equilibrium characteristics by providing a shield on the secondary winding portion, as in the conventional zero-phase current transformer. To use.

As shown in FIG. 1, the fixed zero-phase current transformer 3
Improving the equilibrium characteristics is attempted by arranging three conductors 2 penetrating through each other linearly on the diameter and fixing them at a predetermined angle 5. The predetermined angle 5 is, for example, an angle from a line parallel to the connecting line (leading line) to the measuring instrument 4 and passing through the center of the zero-phase current transformer 3 as a reference.

The above predetermined angle 5 is obtained as follows. As shown in FIG. 2, two conductors 2 through which a round trip current flows
A and 2B are arranged at the outermost part of the inner diameter of the zero-phase current transformer 3 and the three conductors 2 are bound in a straight line.
The angle at which the output (residual current) of the measuring device 4 measured when B is simultaneously rotated in the directions of arrows 6A and 6B or the opposite direction is determined to be the optimum balance characteristic. In addition,
Actually, since it is difficult to rotate the conductor 2, the zero-phase current transformer 3 is rotated to obtain the predetermined angle 5. This angle 5
Is fixed at 90 degrees, the residual current becomes the smallest.

After the predetermined angle 5 is obtained, as a means for fixing the conductor 2 and the zero-phase current transformer 3 so that the three conductors 2 arranged in a straight line do not move, the conductor 2 is connected to the passing portion thereof. This is achieved by using a solid material that has passed through the through hole.

For example, two pieces having a semicircular shape and made of an insulating material are used, and they are inserted into the gap between the zero-phase current transformer 3 and the three conductors 2 linearly arranged.

FIG. 3 shows the holding / holding of the conductor for the zero-phase current transformer.
It is a figure which shows the example of a position adjusting device. Figure 3 (a) shows holding
FIG. 3 is a perspective view of the position adjusting device, and FIG.

In FIG. 3, 10 is a box-shaped case, and 11
Is two grooves, 12 and 1, which penetrate to the inside of the case 10.
3 is a position adjusting plate for fixing the position of the conductor 2 by rotating the conductor 2 or the zero-phase current transformer 3, and 14 and 15 are screws for fixing the position adjusting plates 12 and 13 to the case 10. Reference numeral 16 is a support plate connected to the position adjusting plates 12 and 13 for supporting the three conductors 2, 17 is a conductor holding plate for holding the three conductors 2 on the support plate 16, and 18 and 19 are the support plates 16 And a screw for connecting the conductor pressing plate 17 to each other.

FIG. 4 is a diagram showing an example of means for fixing the conductor and the zero-phase current transformer.

FIG. 4A shows a conductor 2 and a zero-phase current transformer 3 as a means for fixing the conductor 2 and the zero-phase current transformer 3 so that the three conductors 2 arranged in a straight line do not move. The clay 20 is filled in the gap portion of the.

FIG. 4B shows a supporting member having a U-shaped cross section as a means for fixing the conductor 2 and the zero-phase current transformer 3 so that the three conductors 2 arranged in a straight line do not move. The (molding materials) 21 and 22 are sandwiched from the left and right sides of the zero-phase current transformer 3. The diagram on the right side of FIG. 2B is a side view of the state in which the support member 21 is sandwiched between the zero-phase current transformers 3.

In FIG. 4 (c), the conductors 2 are fixed after being fixed by a jig 25 so that the three conductors 2 arranged in a straight line do not move.
As a means for fixing the zero-phase current transformer 3, support members (mold materials) 23 and 24 having a U-shaped cross section are sandwiched from both upper and lower sides of the zero-phase current transformer 3.

That is, the equilibrium characteristic of the zero-phase current transformer 3 changes depending on the arrangement of the cable (system wire: conductor 2). The electric wire 2 passing the reciprocating current is arranged on the diameter inside the zero-phase current transformer 3, and the cable is rotated while observing the output on the secondary side. The secondary output takes the maximum and the minimum depending on the arrangement of the cables, so the position where the output is the minimum is found. By arranging the three-phase electric wire 2 on the diameter where the secondary output is minimized by the reciprocating current, the balance characteristic can be improved. The balance characteristic is better than the conventional method in which the three-phase electric wires 2 are concentrated.

According to the first embodiment, the zero-phase current transformer 3
Since the equilibrium characteristics are improved and the zero-phase current detection level is improved, it is possible to obtain the leakage current detection accuracy in a minute region which is necessary for diagnosing the insulation deterioration performed in the live line.

[0029]

As described above, the conductor arranging method for the zero-phase current transformer according to the present invention arranges a plurality of conductors penetrating the zero-phase current transformer linearly on the diameter of the penetrating portion. Observing a current flowing through the conductor with a measuring instrument, rotating the plurality of conductors or the zero-phase current transformer to a position where the observed value is minimum, the zero-phase current transformer and the zero-phase current transformer Since the step of fixing a plurality of conductors is included, it is possible to obtain the accuracy of detecting the leakage current in a minute area.

As described above, the conductor arranging method for the zero-phase current transformer according to the present invention includes the first line parallel to the connecting line to the measuring instrument and passing through the center of the zero-phase current transformer, Since the zero-phase current transformer and the plurality of conductors are fixed at a position where the angle with the second line passing through the centers of the plurality of conductors and passing through the center of the zero-phase current transformer is 90 degrees, An effect is obtained that the detection accuracy of the leakage current in the minute area can be obtained.

As described above, the holding / position adjusting device according to the present invention penetrates the zero-phase current transformer and the penetrating portion of the zero-phase current transformer, and is arranged linearly on the diameter of the penetrating portion. Since the plurality of conductors and the means for fixing the plurality of conductors and the zero-phase current transformer are provided, it is possible to obtain the detection accuracy of the leakage current in the minute region.

Further, as described above, the holding / position adjusting device according to the present invention includes the first line parallel to the connecting line to the measuring instrument and passing through the center of the zero-phase current transformer, and the plurality of conductors. The angle with the second line passing through the center of the zero phase current transformer and passing through the center of the zero-phase current transformer is set to 90 degrees, so that there is an effect that the detection accuracy of the leakage current in the minute region can be obtained.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of a conductor arranging method for a zero-phase current transformer according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a conductor arranging method for the zero-phase current transformer according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of a conductor holding / position adjusting device for the zero-phase current transformer according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an example of means for fixing the conductor and the zero-phase current transformer in the method of arranging the conductor for the zero-phase current transformer according to the first embodiment of the present invention.

[Fig. 5] Fig. 5 is a view showing an installation place of a zero-phase current transformer according to the related art and the first embodiment of the present invention.

FIG. 6 is a view showing a cross section of a conventional conductor arranging method for a zero-phase current transformer.

[Explanation of symbols]

2 conductors (system cables), 3 zero-phase current transformers, 4 measuring instruments,
5 Angles that give the best balance characteristics, 10 cases, 11
Groove, 12, 13 Position adjustment plate, 14, 15 Screw, 16
Support plate, 17 Conductor retainer plate, 18, 19 Screws, 20
Clay, 21, 22 support member, 23, 24 support member, 25 jig.

Claims (4)

[Claims] 1. A step of arranging a plurality of conductors penetrating a zero-phase current transformer in a straight line on the diameter of the penetrating portion, and observing a current flowing through the conductor with a measuring instrument, and observing that the observed value is minimum. Zero phase current transformer, the step of rotating the plurality of conductors or the zero phase current transformer to a certain position, and the step of fixing the zero phase current transformer and the plurality of conductors. How to place conductors to. 2. A first line parallel to the connecting line to the measuring instrument and passing through the center of the zero-phase current transformer, and a first line passing through the centers of the plurality of conductors and passing through the center of the zero-phase current transformer. The method for arranging a conductor with respect to a zero-phase current transformer according to claim 1, wherein the zero-phase current transformer and the plurality of conductors are fixed at a position where an angle with the line 2 is 90 degrees. 3. A zero-phase current transformer, a plurality of conductors penetrating a penetrating portion of the zero-phase current transformer and linearly arranged on a diameter of the penetrating portion, and the plurality of conductors. A holding / position adjusting device comprising means for fixing the zero-phase current transformer. 4. A first line parallel to the connecting line to the measuring instrument and passing through the center of the zero-phase current transformer, and a first line passing through the centers of the plurality of conductors and passing through the center of the zero-phase current transformer. The holding and position adjusting device according to claim 3, wherein the angle with the line 2 is 90 degrees.