JPH033608A - How to diagnose electrical wire abnormalities - Google Patents

Abstract

PURPOSE:To detect whether there is any defect at an internal layer or at an external layer, by using two sorts of inspecting coils, and by crossing the while layer section and the external layer section of an electric wire with magnetic flux, to look for the defect. CONSTITUTION:An inspecting coil 1A is supported in a state wound on the longitudinally cracked cylinder of non-magnetic substance, and consists of coils separated from each other at longitudinally cracked sections and connected to each other electrically and mechanically with a connector at the longitudinally cracked sections, and magnetic flux phi is crossed with the whole layer of an electric wire W to be measured. An inspecting coil 1C is a coil wound on a circular-plate-shaped core bent along the peripheral direction of the electric wire W to be measured, and the electric wire W is crossed with the magnetic flux phi mainly near an external layer, along the longitudinal direction of the electric wire W to be measured. First, by using the coil 1A, any defect at the whole layer is looked for, and when any defect is detected, then the section of the defect is looked for by using the coil 1C, and it is discriminated whether the defect is an internal layer defect or an external layer defect.

Description

Detailed Description of the Invention "Industrial Application Field J The present invention relates to a method for diagnosing abnormalities in electric wires, and in particular, by measuring the magnetic characteristics when alternating magnetic flux is applied to the conductor portion of the wire, This system diagnoses abnormalities such as corrosion conditions with high accuracy.

``Prior Art'' When electric wires such as steel-core aluminum stranded wires are placed in an environment such as an overhead wire near the coast, a problem arises in that there is a high risk of corrosion.

As a method for non-destructively inspecting the corrosion status of electric wires, electric wire inspection coil IB-1c.! shown in FIGS. 5(B), (C), and (D) is used. By attaching D to the wire W to be measured and energizing it, alternating magnetic flux crosses the conductor portion and ferromagnetic portion of the wire W to be measured, and whether abnormal phenomena such as corrosion occur due to changes in magnetic properties. Plans are being made to determine the

The electric wire inspection coil IB in FIG. 5(B) is called a probe coil or type, and since the coil is wound along the surface of the electric wire W to be measured, as shown by the broken line, The generated magnetic flux φ mainly crosses the radial direction of the electric wire W to be measured.

The electric wire inspection coil IC shown in FIG. 5(C) is called a split coil type, and a wire ring is wound around an arc plate-shaped iron core curved along the circumferential direction of the electric wire W to be measured. As shown by the broken line, the generated magnetic flux φ mainly crosses the vicinity of the outer layer along the longitudinal direction of the electric wire W to be measured.

The wire inspection coil ID shown in FIG. 5(D) is called a through-coil type, and is made by winding one strand of wire in a spiral around the surface of the wire W to be measured, as indicated by the broken line. As shown, the generated magnetic flux φ is considered to be effective in reaching the inside of the electric wire W to be measured.

"Problem to be Solved by the Invention" However, when inspecting an electric wire using the electric wire inspection coil IB-1c shown in FIGS. 5(B) and (C), the magnetic flux φ is This increases the accuracy of detecting local abnormalities in the outer layer of the wire, but it is difficult to detect abnormalities in the inner layer of the wire.On the other hand, the coil ID for wire inspection Since the magnetic flux φ can cross the inner layer, that is, all the layers of the wire, it is possible to detect the presence or absence of abnormalities in all the layers of the wire. However, with only this wire inspection coil ID, it is possible to detect defects in the outer layer. It is not possible to determine whether it is in the inner layer or not, and since it has to be wrapped around the electric wire W to be measured, there are problems such as poor workability and reduced inspection efficiency.

The present invention has been made in view of the above-mentioned circumstances, and provides high identification of abnormal parts of electric wires, and efficiently performs abnormality diagnosis work.

"Means for Solving the Problems" The present invention proposes two means for solving these problems. Collects characteristic data and determines whether there is an abnormality in all layers of the wire under test. If an abnormality is found, collects magnetic characteristic data by concentrating and intersecting No. 4 magnetic flux near the outer layer of the wire under test. This is a method for diagnosing an abnormality in an electric wire, which is characterized by determining whether or not there is an abnormality in the outer layer portion.

The second method is to collect magnetic data when alternating magnetic flux concentrates and intersects near the outer layer of the wire to be measured, and to determine whether there is an abnormality in the outer layer of the wire to be measured, and if no abnormality is found. A method for diagnosing an abnormality in an electric wire is characterized in that alternating magnetic flux is passed through all the layers of the electric wire to be measured to collect magnetic characteristic data to determine whether or not there is an abnormality in all the layers.

``Effect'' In the first method, if no abnormality is recognized when alternating magnetic flux crosses all layers of the wire under test, it means that the wire under test has no defect and is sound. However, if an abnormality is observed, it means that there is a defect somewhere in the wire to be measured.

Therefore, in this case, the presence or absence of an abnormality in the outer layer is determined by concentrating and crossing the alternating magnetic flux near the outer layer of the wire to be measured, and if no abnormality is found,
It is confirmed that the defect is in the inner layer portion, and if an abnormality is observed, it is confirmed that the defect is in the outer layer portion.

In the second method, if an abnormality is observed when alternating magnetic flux is concentrated and crossed near the outer layer of the wire to be measured, it is confirmed that there is a defect in the outer layer, and if no abnormality is observed, Diagnose whether or not an abnormality is observed in other parts of the wire under test by crossing alternating magnetic flux through all layers of the wire under test. If no abnormality is found in all layers of the wire, If no defects occur and it is confirmed that this is a sound wire, and an abnormality is found in all the layers, it is confirmed that there is a defect in the inner layer of the wire to be measured.

[Example J] Hereinafter, an example of the method for diagnosing electric wire abnormality according to the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a flow for diagnosing the presence or absence of abnormality in electric wires using two types of test coils of different methods.

In this case, two types of test coils are used: one shown in Figure 5 (A), which was developed to have characteristics similar to those shown in Figure 5 (D), and which avoids alternating magnetic flux from crossing all layers of the wire under test. , and the one shown in FIG. 5(C) in which alternating magnetic flux is concentrated and crossed near the outer layer of the wire to be measured is used. Furthermore, the fifth
The inspection coil IA shown in Figure (A) is supported in a wound state around a vertically divided cylindrical body made of a non-magnetic material, and a coiled wire ring that is divided at a vertically divided point is connected to a connector at a vertically divided point. electrically and mechanically coupled, and the fifth
As shown in Figure (A), the magnetic flux φ can be made to cross all layers of the electric wire W to be measured.

These two test coils IA and IC are alternately attached to the wire W to be measured to determine the impedance, and a diagnosis of wire abnormality is performed based on the presence or absence of a difference from the standard wire (healthy wire).

In other words, it is possible to determine whether the detected defect occurs in the outer layer or the inner layer using the logic according to the example evaluation/diagnosis flow shown in the flow of FIG. The diagnostic flow in this case will be explained step by step.

SL: Using the testing coil shown in Figure 5 (A), cross an alternating magnetic flux across the inner and outer layers (all layers) of the wire, and S2: Check whether there is a difference in impedance with a sound wire. The presence or absence of a defect is diagnosed by determining, and if there is no difference, the process moves to S3, and if there is a difference, the process moves to S4.

S3: [It is confirmed that there are no defects in all layers of one diagnostic test piece, and the work is completed.

S4: Using the test coil shown in FIG. 5(C), cross an alternating magnetic flux across the outer layer of the electric wire, and S5: Determine whether there is a difference in impedance with a sound electric wire. If there is no difference or the difference is small, the process moves to S6, and if there is a difference, the process moves to S7.

S6: [Diagnosis 2 It is confirmed that there are no defects in the outer layer portion, and the work is completed.

S7: [Diagnosis 3] It is confirmed that there is a defect in the outer layer portion, and the work is ended.

[Experiment example Next, an experimental example will be explained with reference to FIGS. 2 to 4.

In this experimental example, the impedance was measured in the order of the full-layer inspection coil IA shown in FIG. 5(A) and the outer layer inspection coil Ic shown in FIG. 5(C) according to the flowchart of the embodiment shown in FIG. did.

That is, the test coil IA is attached to the wire W to be measured, its impedance Z+n is measured, and this impedance Z
, n and the impedance Z+o obtained by attaching the test coil IA to a standard electric wire (healthy electric wire), ΔZ, 11=Z In Z +o is determined.

Similarly, the test coil IC is attached to the wire W to be measured, and its impedance Ztn is measured.
Difference between yn and impedance Z20 obtained by attaching the test coil Ic to a standard electric wire ΔZtn=Ztn
Zt. seek.

The specifications of the test coils IA and tC used in the experimental example are as follows.

Specifications for inspection coil IA: Number of close turns of 0/3φ enameled wire = 60 turns Core diameter: 20+nmφ Specifications of inspection coil IC: Number of close turns of 0/3φ enameled wire: 260 turns Center diameter: 20mmφ Coil length (axis Directional dimension): 5 mm Figure 2 shows the electric wire model compared in the experimental example, and sample Sa is a sound electric wire of steel core aluminum stranded wire (ACSR) made by twisting aluminum wire on steel wire. The model, sample sb, is a wire model in which 6 outer layer aluminum wires are missing due to corrosion etc., and sample Sc is a wire model in which 6 inner layer aluminum wires are missing due to corrosion etc. In Fig. 2, The mark (blacked out part) means a missing strand.

For these wire models, frequencies 50 to 100
The aforementioned impedance difference at 0 kHz was determined. The results are shown in FIGS. 3 and 4.

As is clear from FIG. 3, according to the inspection coil IA of the example in FIG. 5(A), the detection sensitivity is good when the wire defect location is in the outer layer and the inner layer, especially as the frequency becomes higher. Therefore, although the difference in impedance becomes significant, the difference in impedance depending on the location where the wire is missing is small, and within the range of this full-layer inspection, no difference in characteristics occurs due to the location where the wire is missing.

On the other hand, as is clear from Fig. 4, Fig. 5 (C
) According to the inspection coil Ic in the example, the detection sensitivity is good when the defective part of the wire is in the outer layer, and the impedance difference between the inner and outer layers becomes a noticeable difference, especially from the low frequency region, so it is easy to detect the defective part. Judgment becomes easier.

In addition, in the explanation based on the flow in FIG. 1, the presence or absence of defects in the outer layer portion is determined after determining the presence or absence of defects in all the layer portions, but a diagnosis method in which the steps of S4 and St are reversed may be used. You can also pick it up.

[Effects of the Invention] According to the method for diagnosing abnormalities in electric wires according to the present invention, two types of testing coils with different methods are used to cross magnetic flux through the entire layer portion and the outer layer portion of the wire, thereby detecting defects in each portion. By determining whether or not there is a defective part, it is possible to diagnose and confirm whether the defective part is located in the inner or outer layer of the wire. By using different coils, it is possible to reliably and quickly identify them.

[Brief explanation of drawings]

Fig. 1 is a flowchart of an embodiment of the electric wire abnormality diagnosis method according to the present invention, Fig. 2 (A) to C) is an explanatory diagram of an electric wire model compared in an experimental example, and Fig. Figure 4 is a frequency characteristic diagram of the impedance difference determined by the layer inspection coil and the wire defect location, Figure 4 is a frequency characteristic diagram of the impedance difference determined by the outer layer inspection coil and the wire defect location, and Figure 5 (A) or D) is an explanatory diagram of a coil model used for electric wire inspection. IA-1, D... Coil for electric wire inspection, W...
...Wire to be measured. Fig.1 Fig.2

Claims (1)

[Claims] 1. Collecting magnetic property data when alternating magnetic flux crosses all layers of the wire to be measured and determining whether or not there is an abnormality in all the layers of the wire to be measured, and when an abnormality is found. A method for diagnosing an abnormality in an electric wire, characterized in that alternating magnetic flux is focused and crossed near the outer layer of the electric wire to be measured, and magnetic property data is collected to determine whether or not there is an abnormality in the outer layer. 2. Collect magnetic data when alternating magnetic flux concentrates and crosses near the outer layer of the wire to be measured, determine whether there is an abnormality in the outer layer of the wire to be measured, and if no abnormality is found, A method for diagnosing an abnormality in a wire, characterized in that alternating magnetic flux is passed through all the layers to collect magnetic property data to determine whether or not there is an abnormality in all the layers.