JP2790476B2 - Lightning arrester failure detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial application field >> The present invention relates to a device for detecting a failure of an arrester.

<< Conventional Technology >> Conventionally, in order to protect electrical equipment from lightning strikes, it is necessary to discharge excessive overvoltages caused by lightning strikes to the power supply lines and signal lines (hereinafter, referred to as signal lines) of the electrical equipment to the ground. Lightning arresters are used.

This lightning arrester is configured by connecting a voltage limiting element and a current limiting element in series, and is used by inserting this into a lead wire wired between a signal line and the ground.

The voltage limiting element is a so-called surge absorber composed of a gap or an element that provides a constant discharge voltage, while the current limiting element is formed of an element having a current characteristic such as controlling a discharge current and blocking a subsequent current. , So-called arresters.

The lightning arrester is indispensable for protecting train control on-site equipment, for example, a traffic light or a point machine from an electric shock.
In particular, recent electronic devices have the drawback that if they are damaged by a lightning strike, the entire control device will need to be replaced and the recovery will take a long time, and the economic damage will increase.

The reason is that the traffic light and the control equipment are kept in an electrically non-contact state by a photocoupler or the like, but when a signal line receives lightning, the internal semiconductor elements etc. rise through the chassis housing the control equipment. This is because they are destroyed by being exposed to the voltage.

Therefore, the lightning arrester is an indispensable protection device for train control.

<< Problems to be Solved by the Invention >> However, in the above-mentioned conventional lightning arrester, there is no effective means for detecting a failure of the lightning arrester. There was an inconvenience that it had to be replaced with a new one on a regular basis.

By the way, as a failure of the lightning arrester, the current control element often fails in the shoot mode due to its structural characteristics.In this case, when the signal line is struck by lightning, the abnormal voltage is discharged to the ground and the control equipment It is protected and can achieve its purpose in the event of a lightning strike. However, even during normal times, not when lightning strikes, the signal line is grounded to the ground, so signal current leaks or noise enters through the lead wires, causing malfunctions of control equipment. there were. Such inconveniences may be particularly problematic in electronic control devices because they are easily affected by the strength of the signal current.

The present invention has been made in order to respond to the demand for a reliable lightning arrester in response to the digitization of a control device connected to a signal line, and an apparatus capable of easily detecting a failure of the lightning arrester. The purpose is to provide.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention has an arrester and a detector, and the arrester has a voltage limiting element and a current limiting element connected in series to perform communication. Line, signal line, or lead wire wired between the power line and the earth.The detector detects the potential at the midpoint of connection between the voltage limiting element and the current limiting element, It is characterized by detecting a lightning arrester failure from the change.

<< Operation >> In a lightning arrester, when a signal line receives lightning, an abnormally high voltage is discharged to the ground via a voltage limiting element, and the continuation of discharge current is interrupted via a current limiting element. This allows
The control device connected to the signal line is protected, and after the discharge, the normal operation of the control device is resumed.

The detector monitors the potential change at the midpoint of the connection between the voltage limiting element and the current limiting element. If the current limiting element fails in the short mode, the potential drops to almost 0 and the surge arrester fails. Is detected.

<< Example >> Hereinafter, the present invention will be described with reference to the drawings.

The drawing is a schematic configuration diagram in a case where the failure detection device for an arrester according to the present invention is applied to a railway signal line.

Figure l _1, l ₂ is connected to one end of the power supply E, and the other end is a signal line of the reciprocating path connected to the photocoupler 1 as a switching element of the control box C, and return l ₁ of the signal line , A signal light is connected in series as a load R.

Therefore, when the light emitting diode 1a of the photocoupler 1 emits light at the output of an electronic control device (not shown), the light beam turns on the light receiving element 1b, so that the light is turned on and the current is supplied from the power source E to the load R. Is done. As a result, a signal lamp as a load is turned on.

On the other hand, when the light emitting diode 1a is turned off, the light receiving element
1b is switched off, the current to the signal lamp is cut off and turned off.

During lightning to the signal lines l _1, l _2, arrester 2 for discharging the abnormal voltage to ground it is provided.

Arrester 2, a known voltage limiting element 3a provided in the lead wire l _3, l _4, one end of which is connected to the signal lines l _1, l _2, and 3b, both of these voltage limiting element 3a, the output end of 3b One end is connected to
The other end is constituted by a well-known current limiting element 4 inserted in a grounded lead ₁₅ .

The detector 5 has a function of an electrometer, and is configured to display an alarm or a warning light when the potential is equal to or lower than a predetermined potential.

One end of the detector 5, a voltage limiting element 3a, are connected to the leads connected l ₅ of 3b and the current limiting element 4, i.e. connected is connected to a midpoint b, leads the other end which is grounded to the earth l Inserted in ₆ .

 The operation of this embodiment having the above configuration will be described.

Assuming that the signal line ₁₁ is lightning-triggered when the lightning arrester 2 is normal, the abnormal voltage is applied to the signal line ₁₁ and the ground via the elements of the voltage limiting element 3a and the elements of the current limiting element 4. conductive path is formed between, thereby the abnormal voltage is discharged to ground, the control device connected to the signal line l ₁ is effectively protected from the abnormal voltage. Note that the signal line l ₂ acts similarly via a voltage limiting element 3b also when the lightning.

After the discharge is completed, the conductive path formed at the time of lightning is cut off based on the characteristics of the current limiting element 4, so that the signal currents of the signal lines l ₁ and l ₂ are prevented from flowing to the ground. The signal lines l ₁ and l ₂ are again maintained in the normal control signal state. Therefore, it is possible to effectively prevent noise from entering the control device from the ground through the conductive path formed during the lightning strike, or malfunction of the controller due to leakage of the signal current.

When the current limiting element 4 is conducting (during lightning), the potential at the connection midpoint A is substantially equal to 0, while when not conducting (normal time without lightning), the voltage of the signal lines l ₁ and l ₂ is Is maintained at or above a predetermined potential.

On the other hand, if any of the signal lines l ₁ and l ₂ receives a lightning strike when the current limiting element 4 has failed in the short mode,
Via the voltage limiting element 3a or 3b and the current limiting element 4,
As in the case of the above-mentioned lightning strike, an abnormal voltage can be released to the ground, and the control equipment is protected for the time being.

However, since the current limiting element 4 is short-circuited, the conductive path formed between each of the signal lines l ₁ and l ₂ and the ground remains as it is even during normal times, and the signal current leaks through this conductive path. Or noise from the ground enters. Therefore, even when the photocoupler 1 is turned on, the current to the load R does not reach the specified value, and a predetermined control operation is not performed. That is, there is a possibility that the signal lamp does not light or a sufficient illuminance cannot be maintained. Occur.

Further, when the signal lines l ₁ and l ₂ transmit control signals to the control device, that is, when the arrangement of each element of the photocoupler 1 is reversed, the control signal cannot be transmitted to the control device, and May malfunction.

In such a situation, the potential at the connection midpoint A is almost 0 because the current limiting element 4 is short-circuited.
Therefore, when the potential of the detector 5 is 0 in a normal state when the lightning is not received, the lightning arrester 2 acts so as to notify the operator of the failure with an alarm or an indicator lamp.

Therefore, the operator can know the failure of the lightning arrester by the alarm or the indicator light, and can quickly replace the lightning arrester, so that the signal transmission state of the signal lines l ₁ and l ₂ can be quickly returned to normal. be able to.

In the present embodiment described above, since the potential at the contact midpoint between the voltage limiting elements 3a and 3b and the current limiting element 4 is detected by the detector 5, the signal lines l ₁ and l ₂ receive lightning. In normal times, when the potential is almost 0, it is possible to easily detect that the current limiting element 4 is short-circuited, that is, that the lightning arrester 2 is out of order.

Therefore, since the failure of the lightning arrester 2 can be detected quickly, there is an effect that the malfunction can be prevented by replacing it with a normal one.

<< Effects of the Invention >> The present invention is configured so that the potential at the midpoint of the contact point between the voltage limiting element and the current limiting element is detected by the detector. When the value is 0, it is possible to easily detect that the current limiting element of the surge arrester is in a short-circuit state and has failed.

Therefore, the lightning arrester can be promptly replaced with a normal one, so that a malfunction of the control device can be efficiently prevented.

Further, it is not necessary to replace the normal lightning arrester indiscriminately as in the related art, and the economic efficiency can be improved.

[Brief description of the drawings]

The drawing is a schematic configuration diagram in a case where the failure detection device for an arrester according to the present invention is applied to a railway signal line. 1 ...... photocoupler, 2 ...... arrester, 3a, 3b ...... voltage limiting element, 4 ...... current limiting element, 5 ...... detector, l _1, l ₂ ...... signal line, E ...... power, R ... ... Load (signal light).

Claims (1)

(57) [Claims] 1. A lightning arrestor and a detector are provided. (B) The lightning arrester has a voltage limiting element and a current limiting element connected in series, and is connected to a communication line, a signal line or a transmission line. (C) the detector detects the potential at the midpoint of connection between the voltage limiting element and the current limiting element, and detects the potential from a change in the detected value. A failure detector for an arrester, which detects a failure of the arrester.