JP2004117207A - Accident point locating method for cable line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an accident point locating method for a cable line for locating an accident point without destroying a device in location of the accident point in the cable line. <P>SOLUTION: After a direct current voltage is generated from a discharge continuing direct current power source 4, a control signal is transmitted to an impulse voltage generation part 2 for generating an impulse voltage to superimpose it on the direct current voltage, and this is impressed to a cable terminal part 21 in the cable line 20 to cause arc discharge at the accident point with high resistance for lowering the resistance. When the arc discharge occurs at the accident point and a cable line voltage monitored by a voltage monitoring part 40 is lowered, a control part 30 gives a closing command to a high voltage switch 7, and a locating pulse is injected to the cable line 20 from a locating pulse generation part 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for locating a fault on a cable line, and more particularly, to a method for locating a fault on a cable line that can locate a fault without damaging a device.
[0002]
[Prior art]
As a conventional method for locating a fault on a cable line, for example, a discharge pulse for inducing a discharge at a fault point on a cable line where power supply is stopped is injected, and a pulse for fault point locating is performed during discharge. There is known a method of locating an accident point from a waveform of a reflected wave by injecting the reflected wave into a cable line.
[0003]
FIG. 2 shows an accident point locating device used in such a conventional cable line accident point locating method. The fault point locating apparatus 1a includes an impulse voltage generating unit 2 for causing a discharge at the fault point, a switch 3 for applying an impulse voltage generated by the impulse voltage generating unit 2 to a cable terminal unit 21, A DC power source 4 for continuation of discharge, a protection unit 5 composed of a blocking coil and a diode for protecting the DC power source 4 for continuation of discharge from an impulse voltage, and a pulse for locating a fault point during a discharge at a fault point. 21; a high-voltage switch 7 for connecting the cable terminal 21 and the locating pulse generator 6 during the injection of the locating pulse; and an accident by detecting a reflected wave from the accident point. A control unit 31 connects a locating unit 8 for locating a point, an impulse voltage generating unit 2, a DC power source 4 for continuation of discharge, a protection unit 5, a locating pulse generating unit 6 and a high voltage switch 7 via a control line 31. And a control unit 30a for controlling Te.
[0004]
The accident point locator 1a operates as follows. The control unit 30a generates a DC voltage from the DC power source 4 for continuing discharge, transmits a control signal to the impulse voltage generation unit 2, generates an impulse voltage, and superimposes the impulse voltage on the DC voltage. An arc current is applied to the cable end portion 21 to cause an arc discharge at a high-resistance accident point (not shown) to flow an arc current. At this time, the accident point has low resistance. The control unit 30a transmits a control signal to the locating pulse generator 6 while the resistance is low, and transmits a locating pulse from the locating pulse generator 6 to the cable terminal unit 21 via the high voltage switch 7. inject. The locating unit 8 detects the reflected wave of the locating pulse from the accident point by the sensor 22, and locates the distance from the cable terminal unit 21 to the accident point. In this way, since the location pulse is injected after the fault point has a low resistance, the distance from the cable terminal 21 to the fault point can be reliably located.
[0005]
[Problems to be solved by the invention]
However, according to the conventional fault point locating method, after the impulse voltage is applied, since the locating pulse is applied regardless of whether or not arc discharge occurs at the fault point, when arc discharge does not occur at the fault point, There is a problem that the impulse voltage remains in the cable line 20 and the impulse voltage is applied to the locating pulse generation unit 6 to possibly destroy the locating pulse generation unit 6.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for locating an accident point on a cable line, which can locate an accident point without damaging the device when locating an accident point on the cable line.
[0007]
[Means for Solving the Problems]
The present invention, in order to achieve the above object, injecting a locating pulse from the end of the cable line, in the fault point locating method of the cable line to locate the fault point based on the reflected wave waveform of the locating pulse, An application step of applying a DC voltage to the cable line and applying an impulse voltage to the cable line to cause an arc discharge at the accident point to cause an arc current to flow, and a monitoring step of monitoring a line voltage of the cable line. An injection step of injecting the positioning pulse into the cable line when the line voltage monitored in the monitoring step decreases after the application of the DC voltage and the impulse voltage. Provide an accident point location method.
[0008]
According to this configuration, by monitoring the line voltage of the cable line, it is possible to determine whether the impulse voltage remains in the cable line, and it is possible to inject the positioning pulse when the impulse voltage does not remain. It becomes.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an accident point locating device for a cable line according to an embodiment of the present invention. The fault point locating device 1 includes an impulse voltage generator 2 for causing a discharge at the fault point, a switch 3 for applying an impulse voltage generated by the impulse voltage generator 2 to a cable terminal 21, A DC power source 4 for continuation of discharge, a protection unit 5 composed of a blocking coil and a diode for protecting the DC power source 4 for impulse voltage from an impulse voltage, and a positioning pulse is injected into the cable line when a fault occurs during discharge. The positioning pulse generator 6, the high voltage switch 7 for connecting the cable line 20 and the positioning pulse generator 6 at the time of injection of the positioning pulse, the voltage monitoring unit 40 monitoring the voltage of the cable line 20, and the sensor 22. Locating unit 8 for detecting the reflected wave from the fault point through the fault and locating the fault point; impulse voltage generating unit 2; DC power source 4 for continuation of discharge; Use the pulse generator 6, and a control unit 30 which controls via a control line 31 to high-voltage switchgear 7 and the voltage monitoring unit 40.
[0010]
The accident point location device 1 operates as follows. The control unit 30 generates a DC voltage from the DC power source 4 for continuous discharge, transmits a control signal to the impulse voltage generation unit 2 to generate an impulse voltage, and superimposes the impulse voltage on the DC voltage. The voltage is applied to the cable terminal 21 to cause an arc discharge at a high-resistance accident point to lower the resistance. When an arc discharge occurs at the accident point and the cable line voltage monitored by the voltage monitoring unit 40 decreases, the control unit 30 issues a command to close the high withstand voltage switch 7, and the orientation is performed by the orientation pulse generation unit 6. The pulse for injection is injected into the cable line 20, and the locating unit 8 detects a reflected wave from the accident point via the sensor 22 to perform accident point locating for locating the accident point.
[0011]
When the arc discharge does not occur at the accident point and the cable line voltage monitored by the voltage monitoring unit 40 does not decrease, the control unit 30 does not output the close command of the high voltage switch 7 and outputs the DC power source 4 for continuation of discharge or the impulse. The voltage generator 2 and the like are stopped.
[0012]
According to this embodiment, when the cable line voltage monitored by the voltage monitoring unit 40 decreases, a positioning pulse is injected, and when the cable line voltage does not decrease, the closing command of the high voltage switch 7 is output. Since this is not performed, no impulse voltage is applied to the locating pulse generator 6 and the locating pulse generator 6 is not destroyed. In addition, if the high-voltage switch 7 is normally opened, the locating pulse generator 6 can be protected from an overvoltage flowing into the locating pulse generator 6 from the cable line 20 for some reason.
[0013]
【The invention's effect】
The method for locating an accident point on a cable line according to the present invention determines whether or not an impulse voltage remains in the cable line by monitoring the line voltage of the cable line. Since the pulse is injected into the cable line, the accident point can be located without damage to the device when the accident point is located on the cable line.
[Brief description of the drawings]
FIG. 1 shows an accident point locating device for a cable line according to an embodiment of the present invention.
FIG. 2 shows a conventional fault locating device for a cable line.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Accident point locating device 1a Accident point locating device 2 Impulse voltage generating unit 3 Switch 4 DC power supply for continuation of discharge 5 Protecting unit 6 Locating pulse generating unit 7 High voltage switch 8 Locating unit 20 Cable line 21 Cable terminal unit 22 Sensor 30 Control unit 30a Control unit 31 Control line 40 Voltage monitoring unit

Claims (2)

Injecting a locating pulse from the end of the cable line, in the fault point locating method of the cable line to locate the fault point based on the waveform of the reflected wave of the locating pulse,
Applying a DC voltage to the cable line and applying an impulse voltage to the cable line to cause an arc discharge at the accident point to cause an arc current to flow,
A monitoring step of monitoring a line voltage of the cable line;
An injection step of injecting the orientation pulse from an end of the cable line when the line voltage monitored in the monitoring step is reduced after the application of the DC voltage and the impulse voltage. A method for locating accident points on railway tracks. The injection step uses a locating pulse generator that generates the locating pulse and a switch for injecting the generated locating pulse into the cable line, and switches the switch when the line voltage decreases. 2. The fault locating method for a cable line according to claim 1, wherein the positioning line is closed, and the locating pulse is injected from an end of the cable line.

Images