JP2001324532A - Continuity confirming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm in no contact the continuity of a high-voltage cutout fuse and the connection section of an insulated wire or the like. SOLUTION: Current transformers 8 and 11 are pinched at both ends of continuity confirmation portions such as the high-voltage cutout fuse(CF) 1 and the connection section 6 of the insulated wire 2 or the like, and a high-frequency pulse signal having specific periodicity is injected to the insulated wire 2 connected to one side of the CF1 from the current transformer 8. The high-frequency pulse detected by the current transformer 11 fitted to the insulated wire 2 on the opposite side of the CF2 is judged by a judging unit 10, and continuity or noncontinuity is confirmed based on the peak voltage value of the detected pulse signal and its periodicity. The threshold value for continuity judgment is lowered in sequence from a high level during a setting action, the lowering of the level is stopped when periodic pulses are detected, and the level is set to the peak voltage value in a complete continuity state. The continuity of the continuity confirmation portion can be confirmed in no contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuity check method for checking the continuity of an electrical connection such as a high-voltage cutout fuse or a connection of an insulated wire.

[0002]

2. Description of the Related Art As a means for confirming conduction of a high-voltage cutout fuse, a connection portion of an insulated wire, and the like, a tester, a megohm meter, and the like are conventionally known. For example, to check the continuity of the high-voltage cutout fuse 1, the insulated wire 2, and the connection portion 6 using the tester, the megaohm meter, or the like,
As shown in FIG. 7, at both ends of the high-voltage cutout fuse 1, for example, at the connection portion 6, the tip of the measuring lead 9 a of the tester 8 is brought into contact with the conductor 2 b of the insulated wire 2, and a loop circuit including the tester 8 is made. Is electrically configured. Then, when the resistance value measured by the tester 8 falls below a preset threshold value, it can be determined that there is conduction.

[0003]

However, in order to confirm the continuity by the above-mentioned method, the conductor of the insulated wire must be exposed to the outside, and the connection between the high-voltage cutout fuse 1 and the insulated wire 2 is required. It is not possible to confirm the presence or absence of continuity in a state where all parts are covered. Also,
Contacting the measurement lead wire 9a with the conductor of the high-voltage insulated wire 2 involves danger and poses a safety problem.
The present invention has been made in order to solve the above-described problems of the related art, and an object thereof is to determine the continuity of a connection portion of a high-voltage cutout fuse or an insulated wire without electric contact. And a safe and efficient continuity check operation can be performed.

[0004]

A first current transformer (hereinafter referred to as CT) is attached to an insulated wire to which a high-voltage cutout fuse (hereinafter referred to as CF) is connected. A transmitter is connected to the first CT, and a high-frequency pulse current having a frequency component of at least 100 kHz and oscillated by the transmitter is repeatedly injected into a specific electric wire. Since a high-frequency pulse current having a steep rise can be considered in the same manner as a surge, when there is conduction in a CF, an insulated wire, and a connection portion thereof, the high-frequency pulse current induced by the first CT returns to the ground as a return path. Propagate. This allows
The high-frequency pulse signal can be propagated to the conduction confirmation portion without being in electrical contact with the CF, the insulated wire, and the connection portion thereof. On the other hand, when there is no conduction between the CF, the insulated wire, and the connection portion, an open end exists between the two, and the high-frequency pulse current does not propagate. A second CT is attached to the other insulated wire to which the CF is connected to detect the high-frequency pulse current. And the second CT
The conduction of the conduction confirmation part is confirmed from the voltage value and the periodicity of the high-frequency pulse detected in step (1). According to the above method, it is possible to judge the continuity of the connection portion of the high-voltage cutout fuse or the insulated wire in a non-contact manner, and to perform a safe and efficient continuity check.

[0005] The present invention can also be configured as follows. (1) The first and second CTs have a structure in which half-broken cores are opposed to each other and sandwiched between insulated wires, and a part of the core is wound with a coil to act as a current transformer.
Thereby, the first and second CTs can be easily attached to both ends of the conduction confirmation portion. (2) The high-frequency pulse detected by the second CT includes high-frequency noise having a pulse at irregular time intervals, and the detected signal has a periodic frequency of the commercial frequency and its harmonics. Noise may be included. Therefore, the predetermined period of the high-frequency pulse injected from the first CT is different from the commercial frequency of 50 Hz, 60 Hz, and its harmonics. Thus, the conduction can be confirmed without being affected by the periodic noise of the commercial frequency and its harmonics. (3) The voltage value of the high-frequency pulse signal detected by the second CT exceeds a threshold value set in advance to a value exceeding the voltage value of the noise, and the high-frequency pulse injected from the first current transformer If the periodicity of the signal and the periodicity of the high-frequency pulse signal detected by the second current transformer match at a preset frequency, it is determined that there is conduction in the conduction confirmation portion. During the setting operation, the threshold value of the conduction judgment is gradually lowered from a high level, and when a periodic pulse is detected, the level is stopped from being lowered, and the threshold value is set according to the peak voltage value in a state where there is complete conduction. It should be left. At this time, the period of the continuously oscillating high-frequency pulse current may be changed into the first CT while being changed at certain intervals.

[0006]

FIG. 1 is a diagram showing a method for confirming conduction according to an embodiment of the present invention. As shown in FIG.
A high-frequency pulse injection CT8 and a high-frequency pulse detection CT11 are sandwiched from above the coating. The high-frequency pulse injection CT8 and the high-frequency pulse detection CT11 are, for example,
It is a structure in which half-broken cores are sandwiched between insulated wires facing each other, and acts as a current transformer by winding a coil around a part of the core. The high-frequency pulse generator 7 is connected to the high-frequency pulse injection CT 8 to inject a high-frequency pulse current from the high-frequency pulse injection CT 8. The determiner 10 is connected to the high-frequency pulse detection CT 11 to determine the high-frequency pulse detected by the high-frequency pulse detection CT 11 and discriminate it from noise.

FIG. 2 is a diagram showing a waveform example of a high-frequency pulse current injected into the high-frequency pulse injection CT 8. In the case of the waveform shown in FIG.
3 ms. As a result, the commercial frequency of 50 Hz
Or it can be easily distinguished from the periodic noise of 60 Hz and its harmonics. FIG. 3 shows a high-frequency pulse detecting CT1 when the conduction confirmation portion is conducting.
FIG. 3 is a diagram illustrating a waveform example of a high-frequency pulse signal detected in 1. When a steeply rising pulse current having a frequency component of 100 Hz or more is injected as shown in FIG. 2, a high-frequency pulse signal having a waveform as shown in FIG. 3 is induced in the insulated wire 2 sandwiched between the high-frequency pulse injection CTs 8. To propagate. Here, the high-frequency pulse current is injected from the high-frequency pulse oscillator 7 into the high-frequency pulse injection CT 8 so that the peak voltage value of the high-frequency pulse signal induced in the insulated wire 2 exceeds the noise voltage value.

Before removing the old fuse 5 in the high-voltage cut-out fuse 1, the decision unit 10 sets a threshold value in accordance with the peak voltage of the high-frequency pulse signal detected by the high-frequency pulse detection CT 11. That is, the threshold value is set to a value slightly lower than the peak voltage value of the high-frequency pulse signal in the state where conduction is present. Judge 1
A clock having a cycle of a pulse oscillated by the high-frequency pulse oscillator 7 is set to 0, and the periodicity of a pulse signal having a peak voltage value exceeding a threshold value can be determined. During the setting operation, the threshold is sequentially lowered from a high level, and when the periodic pulse signal synchronized with the clock is detected, the lowering of the level is stopped, thereby setting the threshold to the peak voltage value of the high-frequency pulse signal. Can be set at a slightly lower value.

FIG. 4 is a diagram showing a waveform example of a high-frequency pulse signal detected by the high-frequency pulse detecting CT 11 when there is no conduction. When the old fuse 5 is removed from the high-voltage cut-out fuse 1, the peak voltage value of the high-frequency pulse signal becomes extremely small or almost 0 mV as compared with the case where there is conduction. Next, when a new fuse is inserted into the high-voltage cutout fuse 1 and the fuse 5 is not in contact with the upper electrode 3 and the lower electrode 4, the peak voltage of the high-frequency pulse signal detected by the high-frequency pulse detection CT 11 is determined in advance. This is far below the set threshold value. On the other hand, when a new fuse is correctly and completely inserted into the high-voltage cutout fuse 1, the fuse 5 comes into contact with the upper electrode 3 and the lower electrode 4, and the peak voltage of the high-frequency pulse signal detected by the high-frequency pulse detection CT11 is: The value exceeds a preset threshold. Here, if the periodicity of the high-frequency pulse signal is synchronized with the clock, it is considered that this signal has propagated through the conduction confirmation portion, and thus the interval between the high-frequency pulse injection CT8 and the high-frequency pulse detection CT11. Can be confirmed to exist.

FIG. 5 is a diagram showing an example of the configuration of the decision unit 10. As shown in FIG. In the figure, reference numeral 7 denotes a high-frequency pulse oscillator that generates a high-frequency pulse current at a predetermined cycle T. The high-frequency pulse oscillator 7 is provided with an output level adjuster 7a. The peak value (voltage value) of the high-frequency pulse current output from the oscillator 5 can be adjusted. The high-frequency pulse current generated by the high-frequency pulse oscillator 7 is injected into the insulated wire 2 by the high-frequency pulse injection CT 8. Reference numeral 10 denotes a determiner, and a determiner 1
0 is provided with comparators 21a and 22a, and the comparators 21a and 22a generate an output pulse when the detected high-frequency pulse signal is larger than the set voltage set by the set resistors 21b and 22b. The sensitivity of the comparator 22a is set to be about twice the sensitivity of the comparator 21a, and the operating level of each of the comparators 21a and 22a can be adjusted by adjusting the setting resistors 21b and 22b that are linked.

As described above, the setting resistors 21b and 22b can set the threshold value at which the determinator 10 generates an output in accordance with the peak value of the pulse signal detected by the high-frequency pulse detecting CT11. . Reference numeral 21c denotes a periodicity determining circuit for determining the periodicity of the pulse signal. For example, as shown in FIG. 6, the pulse interval T output from the comparator 21a falls within a predetermined range (T1 <T <T1 + Δ).
T), and latches the latch circuit 21d. By providing the periodicity determination circuit 21c, the latch circuit 21d is not latched by noise or the like whose pulse interval is not close to T (T1 <T <T1 + ΔT), so that malfunction due to noise or the like can be reduced. it can. Light emitting diodes (LED) 21e, 22e are connected to the outputs of the latch circuit 21d and the comparator 22a, and the latch circuit 21d is latched.
Generates an output, the corresponding LED is turned on.

In order to check the continuity by using the above-described determiner, first, only the LED 22e is turned on by noise on the insulated wire 2 in a state where no pulse is injected from the high-frequency pulse injection CT 8 to the insulated wire 2. And setting resistor 2
Adjust 1b and 22b. Next, before removing the old fuse in the high-voltage cutout fuse 1 as described above, a harmonic pulse current is injected into the insulated wire 2 from the high-frequency pulse injection CT 8, and both the LEDs 21e and 22e are reliably turned on. Make sure that LED 21e, 2
When 2e does not light, the output level of the harmonic pulse oscillator 7 is increased by the output level adjuster of the harmonic pulse oscillator 7.

By performing the above-described calibration, it becomes possible to discriminate between noise on the insulated wire 2 and a single high-frequency pulse injected from the high-frequency pulse oscillator 7.
Next, as described above, the high-frequency pulse detecting CT11 is used.
In accordance with the peak voltage of the high-frequency pulse signal detected in
The threshold values are set by adjusting the setting resistors 21b and 22b. Thereafter, as described above, the old fuse 5 is removed from the high-voltage cutout fuse 1, a new fuse is inserted, and the lighting state of the LED 21e is checked. This allows
The conduction state of the conduction confirmation portion can be confirmed. Note that the above determination can be made by using a processor instead of the circuit shown in FIG.

In the above embodiment, the high-frequency pulse injection CT
Although the description has been given of the case of injecting a high-frequency pulse current having a constant period from 8, the repetition period of the high-frequency pulse to be injected is made variable at predetermined intervals in the middle so that high-frequency pulses of a plurality of frequencies are injected into the same insulated wire. It may be. For example, a first pulse oscillator having a repetition period of 75 kHz and a second pulse oscillator having a repetition period of 85 kHz are prepared, and a pulse generated by the first pulse oscillator and a pulse generated by the second pulse oscillator are supplied for a predetermined time. It is switched every time and injected alternately from the high-frequency pulse injection CT 8 into the insulated wire 2. Then, the determination circuit 10 determines whether or not the high-frequency pulse detected by the high-frequency pulse detection CT 11 has the periodicity. By doing so, the conduction check can be reliably performed without being further affected by noise.

[0015]

As described above, in the present invention, a high-frequency pulse signal is periodically and continuously injected into an insulated wire including a continuity check portion by the first current transformer and passed through the continuity check portion. The high-frequency pulse transmitted by the second current transformer is detected by the second current transformer, and the conduction is checked based on the voltage value and the periodicity. Can be determined, and a safe and efficient continuity check operation can be performed. Also, by using a half-core current transformer,
The current transformer can be easily attached to the insulated wire.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conduction confirmation method according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a waveform example of a high-frequency pulse current injected into a high-frequency pulse injection CT.

FIG. 3 shows a C for detecting a high-frequency pulse when there is conduction.
FIG. 3 is a diagram illustrating a waveform example of a high-frequency pulse signal detected at T.

FIG. 4 is a diagram illustrating a waveform example of a high-frequency pulse signal detected for high-frequency pulse detection when there is no conduction;

FIG. 5 is a diagram illustrating a configuration example of a determiner 10;

FIG. 6 is a diagram illustrating an example of a method of determining periodicity of a pulse signal.

FIG. 7 is a diagram showing a conventional conduction checking method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High voltage cutout fuse 2 Insulated wire 2a Insulated wire conductor 3 Upper electrode 4 Lower electrode 5 Fuse 6 Connection part 7 High frequency pulse oscillator 8 High frequency pulse injection CT 9a Measurement lead wire 9b Coaxial cable 10 Judge 11 High frequency pulse detection CT

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Sato 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Kiyoshi Yamada 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Hiroshi Yamamoto 2-2-2 Yoyogi, Shibuya-ku, Tokyo East Japan Railway Company (72) Inventor Takao Fukushi 2-2-2 Yoyogi, Shibuya-ku, Tokyo No. East Japan Railway Company (72) Inventor Jun Miura 2-2-2 Yoyogi, Shibuya-ku, Tokyo East Japan Railway Company F-term (reference) 2G014 AA13 AB43 AB46 AC17 5G502 AA05 AA18 GG01

Claims (5)

[Claims] 1. A method for confirming the presence or absence of continuity of an electrical connection portion, comprising: injecting a high-frequency pulse into one of the insulated wires of the continuity check portion periodically using a first current transformer; In the other insulated wire of the continuity check portion, the second current transformer detects the high-frequency pulse propagated through the continuity check portion, and the plurality of high-frequency pulses detected by the second current transformer are detected. A continuity check method characterized by non-contact checking of continuity in a continuity check portion from a voltage value and a periodicity of a high-frequency pulse. 2. A first current transformer using a half core and attached to one of the insulated wires and the other insulated wire of the continuity check portion, and a first current transformer attached to one of the insulated wires. 2. A pulse signal having a frequency component distinguishable from a commercial frequency and its harmonics is injected from a transformer, and the pulse signal is detected by a second current transformer attached to the other insulated wire. How to check continuity. 3. The voltage value of the high-frequency pulse signal detected by the second current transformer exceeds a threshold value set in advance to a value exceeding a noise voltage value, and the first current transformer When the periodicity of the high-frequency pulse signal injected from the transformer and the periodicity of the high-frequency pulse signal detected by the second current transformer match at a preset frequency, it is determined that there is conduction in the conduction confirmation portion. 3. The method according to claim 1, wherein the conduction is confirmed. 4. A repetition frequency of a commercial frequency of 50 Hz,
2. The method according to claim 1, wherein a high-frequency pulse having a frequency different from 60 Hz and its harmonics is repeatedly oscillated, and is periodically injected from the first current transformer into one of the insulated wires of the conduction confirmation portion. 4. The method according to claim 2, wherein 5. The method according to claim 1, wherein a repetition period of a high-frequency pulse to be injected into one of the insulated wires of the continuity check portion is changed at predetermined intervals on the way, and a plurality of high-frequency pulses are injected into the same insulated wire. 5. The method of claim 1, wherein the continuity is checked.