JPH068840B2 - Receiver for accident point exploration - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for accident point search for applying a high voltage pulse to search for a discharge ground fault point on an overhead distribution line.

[Conventional technology]

As a conventional receiving device for detecting an accident point of an overhead distribution line, there is one using a "signal arrival direction detecting device" disclosed in, for example, JP-A-59-68678. This conventional device will be described with reference to the drawings.

Fig. 8 is a block diagram of the receiver for this accident point exploration. (1) is an overhead distribution line that seems to have a discharge-induced ground fault, and (4A) and (4B) are this distribution line (1). An electromagnetic wave detection antenna that detects electromagnetic waves emitted by a current traveling wave propagating from the accident point above, (5) is a receiving device, and the antenna (4
A) and (4B) are connected respectively. Waveform (I) in the figure
Indicates the first wave of the fault current flowing through the distribution line (1).

(9A) and (9B) are absolute value circuits that output a positive voltage signal by inputting signals from the antennas (4A) and (4B), (10A) and (10B)
Is a monostable multivibrator that outputs a single pulse with the required pulse width Td by the signal input from the absolute value circuits (9A) and (9B). (11A) and (11B) are connected to each other's input / output terminals. A NAND circuit element that constitutes a flip-flop circuit. (12A) and (12B) are inverters that invert the signal level of the input signal and output it, and (13A) and (13B) are signal indicators.

Next, this operation will be described.

Assuming now that the antenna (4A) receives the electromagnetic wave earlier than the antenna (4B) by a time difference td, the voltage signal output from the antenna (4A) is first input to the absolute value circuit (9A). The monostable multivibrator (10A) outputs a single-shot pulse having a required time width Td according to the signal output from the absolute value circuit (9A). By inputting this single-shot pulse, NAND
The circuit element (11B) is interlocked, and the output signal of this NAND circuit element (11A) is output for the duration Td of the above input pulse. The signal is inverted by the inverter (12A) and the signal indicator (13A) is turned on. ， Display the direction of the accident point.

Then, when the antenna (4B) receives the electromagnetic wave and outputs a voltage signal, the same operation is performed.
Since the ND circuit element (11B) is interlocked with the NAND circuit element (11A), the signal indicator (13B) is not input and does not light up.

[Problems to be solved by the invention]

However, according to the above conventional device, in addition to the regular electromagnetic waves in which the current traveling wave propagating from the accident point to the distribution line is generated due to the ground fault discharge, for example, various foreign sources generated from nearby factories, private houses, and broadcasting facilities. There were problems such as receiving noise and displaying it incorrectly.

The present invention has been made to solve the above-described problems, and it is possible to prevent erroneous display by detecting persistent noise or intermittent noise that occurs intermittently in a short cycle of external noise. The purpose is to obtain a receiving device for accident point search that can be performed.

[Means for solving problems]

The accident point detection receiver according to the present invention inputs a time difference signal output means for outputting a pair of signals having a time difference according to an output signal of an antenna and an output signal of the time difference signal output means to determine a time difference between the input signals. A signal corresponding to a normal input signal or a noise signal by inputting an output signal of the time difference expansion means and an output signal of the time difference signal output means, which is expanded more than the time difference of And a signal fixing means for triggering by an output signal corresponding to the regular input signal and outputting a first-arrival signal corresponding to the accident point direction which is being output from the signal time difference expanding means by itself. It is equipped with.

[Action]

In the accident point exploration receiving device according to the present invention, the signal time difference expanding means expands the minute time difference of the input signal from the time difference signal outputting means to a predetermined time difference or more and outputs it.
The noise signal detection means determines whether the input signal from the time difference signal output means is a noise or a normal input signal depending on whether the time length of the input signal is longer or shorter than a predetermined time, and the noise signal detection means corresponds to the noise or the normal input. A signal is output, and the signal fixing circuit is triggered by the output signal corresponding to this regular input. At this time, the first-come-first-served signal corresponding to the fault point direction of the distribution line being output from the signal time difference expanding means is this signal fixing circuit. And hold and output.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. The same reference numerals as those in the conventional example indicate the same or corresponding portions. In Fig. 1, (1) is an overhead distribution line that appears to have a discharge-to-ground fault and is in a power failure state. (3) is the accident equipment connected to the unknown point B of this distribution line (1) and has caused a discharge-induced ground fault, and (2) is the means for applying high voltage pulse (section) that intermittently generates high voltage pulses. It is a power supply device) and is connected to the distribution line (1) at point A, and the distribution line (1) is charged by applying one high voltage pulse. (4A) and (4B) are electromagnetic wave detection antennas for detecting the electromagnetic waves emitted by the current traveling wave propagating from the accident point on the distribution line (1),
Usually, a loop antenna is used and is installed in series with respect to the traveling direction of the automobile (7), for example, on the roof of the automobile (7) at an appropriate distance l (m). (8) is the arrival time difference td of the signals received by the pair of antennas (4A) and (4B).
It is a receiving device that determines the direction of the accident point, and
A) and (4B) are connected via coaxial cables (6A) and (6B), respectively, and mounted on the automobile (7). The waveform (I) in the figure shows the first wave of the fault current flowing through the distribution line (1).

FIG. 2 is a block diagram of the receiving device (8), and (9) is a time difference signal output means for inputting the output signals of the antennas (4A) and (4B) and outputting a signal having two time differences, In this embodiment, an absolute value circuit (9) that widens the input signal and always outputs a positive voltage signal regardless of the polarity of the input signal (9
It is composed of A) and (9B).

Reference numeral (10) is a signal time difference expanding means for expanding the minute time difference td of the output signals of the time difference signal output means (9) to a predetermined time difference or more and outputting the signal, and a pair of monostable multivibrator (1
0A), (10B) and a pair of flip-flop circuits
It is composed of NAND circuit elements (11A) and (11B). (16) inputs the output signal of the time difference signal output means (9) and determines whether this input signal is a noise signal or a normal input signal based on a ground fault discharge at an accident point, and a noise signal or a normal input A noise signal detecting means for outputting a signal corresponding to the signal, which is a monostable multivibrator with a re-trigger function for outputting a single-shot pulse signal having a time length Ti obtained by adding the time length of the input signal to a predetermined time length Tf. Triggered by the leading edge of the output pulse signal of (16A) and this monostable multivibrator (16A), a predetermined time shorter than the output pulse time length Td of the above monostable multivibrator (10A), (10B) A monostable multivibrator (17) that outputs a single-shot pulse signal of long Te and this monostable multivibrator
A monostable multivibrator (18) that is triggered by the trailing edge of the output pulse of (17) and outputs a single-shot pulse of a predetermined time width Ts, and this monostable multivibrator (18)
AND circuit element (19) that receives the output pulse signal of the monostable multivibrator (16A), and the output pulse signal of the monostable multivibrator (18) and the inverted output pulse of the monostable multivibrator (16A) It is composed of an AND circuit element (20) which receives a signal.

(15) is triggered by an output signal corresponding to the normal input signal of the noise signal detecting means (16), that is, an output signal of the AND circuit element (20), and at that time, the signal time difference expanding means
It is a signal fixing means for self-holding and outputting the output signal of (10). This is a pair of D type positive edge trigger type flip-flop circuit elements with reset terminals (hereinafter D
-Flip-flop circuit element) (15A) and (15B). The D-flip-flop circuit elements (15A) and (15B) are connected to the input terminal D at that time due to the rise of the signal input to the terminal T (clock input terminal).
The signal of is held by itself and output from the terminal Q,
Even if the signal at the terminal D changes thereafter, the output state does not change and is held until the reset signal is input to the terminal unless the input signal at the terminal T changes (rises). (21) is a monostable multivibrator which receives the output pulse of the AND circuit (19) and outputs a single-shot pulse from the terminal Q at the leading edge of the input signal. (22) is a signal indicator for inputting the output pulse signal of the monostable multivibrator (21) to indicate the input of a noise signal, and (23) is for resetting the D-flipflop circuit elements (15A), (15B). It is a switch for manual reset that supplies a signal.

Next, the operation will be described. In Fig. 1, the overhead power distribution line (1) in the power failure state is connected to the high-voltage pulse applying means (power supply device) (2).
When charging is performed by applying a high voltage pulse at and the ground fault is discharged at the fault equipment (3), the ground fault current due to the charge charged on the distribution line (1) flows into the fault point B. The rise of the first wave of the transient current in this ground fault discharge is generally extremely steep, and there is a current traveling wave in the distribution line (1) in the direction from the fault point B to the point A toward the point A and to the side C opposite to the point. Propagate in the summer. A car (7) equipped with a pair of antennas (4A), (4B) and a receiving device (8) runs from an electricity application point A toward a non-electrification point side C and is an overhead distribution line.
When (1) is located at an arbitrary point D between the voltage application point A and the accident point B, assuming that (1) is running parallel to this line along the line (1), the above line ( The electromagnetic wave emitted from the current traveling wave propagating in 1) is transmitted to the antenna (4A),
When receiving at (4B), the antenna (4A) on the accident point B side receives first, and the other antenna (4B) receives after delaying by the time difference td. The above car (7) is at the point C opposite to the point where the voltage is applied from the accident point B
When the antennas (4A) and (4B) receive the electromagnetic waves when they are located at, the antenna (4B) at the accident point B side receives the other antenna (4A) earlier by the time difference td. Therefore, of the pair of antennas (4A) and (4B), the direction of arrival of the current traveling wave can be determined by determining which of the electromagnetic waves emitted by the current traveling wave propagating from the accident point was received first. That is, the direction of the accident point can be detected. Since the direction of the fault point can be detected by the intermittent application of the high-voltage pulse by the above-mentioned voltage applying device (2), the antennas (4A) and (4B) and the receiving device (8) are mounted as described above. If the vehicle (7) runs from the charging point (2) along the overhead distribution line (1) while detecting the direction of the accident point, the antenna that receives the electromagnetic wave first will receive the antenna (4A) rather than the antenna ( By changing to 4B), the ground fault accident point B can be inspected.

Next, noise signal detecting means in the receiving device (8) of FIG.
The operation of (16) will be described. FIG. 3 is a time chart at the input / output end of the noise signal detecting means (16) in FIG. 2, where (a) is the case where a normal input signal is input and (b) is the case where a noise signal is input. Show.

Note that the noise signal includes various types of noise such as extremely short noise such as 0.1 ms or less at the output stage of the loop antennas (4A) and (4B), long-lasting persistent noise, and noise that interrupts at short intervals. However, in the embodiment of the present invention, when noise detection is performed for the most abundant persistent noise (for example, one that lasts for 1 ms or more) and intermittent noise (for example, one that occurs intermittently in a cycle of less than 0.5 ms). Is shown.

In the noise signal detecting means (16), when the regular signal shown in FIG. 3 (a) is input, that is, the loop antenna (4A) receiving the electromagnetic wave emitted from the distribution line is changed to A ₀ in FIG. 3 (a). When the signal as shown is output, the monostable multivibrator (16A) is output from the absolute value circuit (9A).
(B) Triggered by inputting a signal such as that shown at A ₁ to terminal B.
(B) As shown in C ₂ and C ₃ , a predetermined time Tf from the time length of the input signal (eg 0.1 ms) due to the rise of the first wave of the input signal
(Eg 0.5 ms) Long time pulse signal Ti (eg 0.6
ms) and the output signal from the terminal Q is input to the terminal B of the monostable multivibrator (17).

The monostable multivibrator (17) is triggered by the rising edge of the leading edge of the input pulse signal.
(B) A pulse signal having a predetermined time width Tc (for example, 1 ms) as shown by C ₄ is output, and this pulse signal is input to the terminal of the monostable multivibrator (18). The monostable multivibrator (18) outputs a pulse signal of a predetermined time duration Tr from the terminal Q at the trailing edge of the trailing edge of the input signal as shown in C ₅ of FIG. 3, and this output pulse signal is an AND circuit element (19 ), (2
It is input to 0) respectively.

The low-level pulse signal is input to the other input terminal of the AND circuit element (20) from the terminal of the monostable multivibrator (16A), but in the case of regular signal input, the time width Ti of this output pulse is The monostable multivibrator (1
Since it is shorter than the output pulse width Tc of 7), the AND circuit element (2
0) outputs the same signal as the output pulse signal of the monostable multivibrator (18) as shown in C ₈ of FIG.
This signal is the output signal corresponding to the regular input signal,
Input to the clock terminal T of the D-flip-flop circuit element (15A), (15B) and the D-flip-flop circuit element
Activate (15A) and (15B). The other input terminal of the NAND circuit element (19) has a monostable multivibrator (16A).
High-level signal is input from the terminal Q of
Contrary to the case of the circuit element (20), the AND circuit element (19) does not output as shown in FIG. 3 C _6, and accordingly, the monostable multivibrator (21) does not operate and the circuit shown in FIG. The noise signal indicator (22) does not light up as shown in C ₇ .

When the noise signal shown in Fig. 3 (b) is input,
That is, when the loop antenna (4A) that receives a noise signal outputs a signal as shown in Fig. 3 (b) A ₀ , a monostable multivibrator with a retrigger function that is retriggered at each rising edge of the input signal ( 16A) is triggered by the rising of the first wave of the output signal of the absolute value circuit (9A) as shown in Fig. 3 (b) A ₁ , and is output from terminal Q and terminal respectively as shown in Fig. 3 (b) C ₂ , C. _As shown in ₃ , the time width of the input signal (1ms
The pulse signal Ti (for example, 1.5 ms or longer) having a longer time than the above (Tf) (for example, 0.5 ms) is output. The AND circuit elements (19) and (20) receive the time as shown in Fig. 3 (b) C ₅ after a predetermined time Tc from the monostable multivibrator (18) as in the case where a normal signal is input. A pulse signal of width Tr is input. At the time of inputting this pulse signal, the time Ti of the output pulse signal of the monostable multivibrator (16A) is longer than Tc.
From (19), the same noise detection signal as the output pulse signal of the monostable multivibrator (18) as shown in FIG. 3 (b) C ₆ is output. By inputting this signal, the time width from the monostable multivibrator (21) to C ₇ in Fig. 3 (b) is shown.
A pulse signal of Tn is output, and the noise signal indicator (22) lights up for Tn time that can be arbitrarily set by the input of this signal, and the noise input is displayed. On the other hand, the above AND circuit element
Contrary to (19), the normal input detection signal is not output from the AND circuit element (20) as shown in C _{8 of} FIG. 3 (b).

Next, the operation of the receiving device (8) in FIG. 2 will be described with reference to FIG. Fig. 4 shows the case where a regular signal is input to the time chart at the input and output ends of each circuit block from the input terminals A ₀ and B ₀ of the receiver (8) to the signal indicators (13A) and (13B). Show. Here, assuming that the electromagnetic wave generated by the current traveling wave from the fault point of the distribution line is received earlier by the loop antenna (4A) than the loop antenna (4B) with a time difference td (for example, 10 ns), the loop antenna ( The operation of each circuit block from the signal input of 4A) and (4B) to the signal output of inverters (12A) and (12B) is the same as the conventional one shown in Fig. 8, and the loop antennas (4A) and (4B) ) And time difference signal output means
The output signals of the absolute value circuits (9A) and (9B) that compose (9) have a time difference td as shown in A ₀ , B ₀ and A ₁ , B ₁ of FIG. 4, respectively.
And a monostable multivibrator (10A), (10B) and a NAND circuit element (11
The output signals of A) and (11B) are as shown in Fig. 4, A ₂ , B ₂ and A ₃ , B ₃ , and they are expanded to the time difference of Td at the output stage of NAND circuit elements (11A) and (11B). Has been done. This NAND circuit element (1
The output signals of 1A) and (11B) are inverted by the inverters (12A) and (12B), and the signals as shown in A ₄ and B _{4 of} FIG.
5) D-flip-flop circuit elements (15A), (15)
Input to terminal D of B). The time width Td (eg, 10 ms) of the output pulse signal of the monostable multivibrator (10A), (10B) is longer than the time length Tc of the output pulse signal of the monostable multivibrator (17) of the noise signal detection circuit. Since it is set, AND of the above noise signal detection means (16)
The output signal corresponding to the fourth normal input such shown in FIG C ₈ outputted from the circuit element (20), the D- flip-flop circuit elements (15A), at the time when (15B) is triggered, the D- flip-flops since only the circuit element (15A) is high-level signal is input to the input terminal D, and this input signal by self-holding, and outputs a continuous signal such as shown from the terminal Q in Fig. 4 a _5, annunciator Turn on (13A) to indicate the direction of the accident point. The D-flip-flop circuit element
The output states from the terminals Q of (15A) and (15B) do not change even if a new signal is input to the terminal D unless there is a rising change of the new input signal to the terminal T. _As shown in ₉ , it is maintained until a reset signal is input to the terminal from the reset switch (23) at an arbitrary time Te.

Next, when the loop antennas (4A) and (4B) receive a continuous noise signal (for example, one that continues for 1 ms or more), the above-mentioned regular signal input is performed until the output stage of the inverters (12A) and (12B). Works as if. However, when a noise signal is input, as described above, the AND circuit element (20) of the noise signal detecting means (16) causes the clock terminals T of the D-flip-flop circuit elements (15A) and (15B) to be input. No signal is input to the D-flip-flop circuit element (1
5A) and (15B) are not triggered, the output state at that time does not change before resetting, and does not output after resetting. Therefore, the signal indicators (13A) and (13B) will not be erroneously displayed.

Also, when an intermittent noise signal is input with a short cycle, for example, the pulse noise signal has a predetermined time length Tf (for example, 0.5 m) of the output pulse of the monostable multivibrator (16A).
s) When inputting intermittently at a shorter interval (not necessarily having the same period), the monostable multivibrator (16A) is able to measure the total length of the intermittent noise signal by the predetermined time length Tf. To output a single-shot pulse signal,
If the time length Ti of this pulse signal is longer than the output pulse time length Tc of the monostable multivibrator (17), the AND circuit element (19) outputs a signal corresponding to the noise signal. That is, it operates in the same manner as when the above-mentioned persistent noise signal is input, and the signal indicators (13A) and (13B) do not erroneously display.

FIG. 5 shows another embodiment of the loop antenna.
(4) is composed of one antenna whose normal to the antenna surface is installed at right angles to the traveling direction of the vehicle (7) in which it is mounted and parallel to the ground.

And the time difference signal output means (9) is the loop antenna (4)
Inverter that intensifies and inverts the output signal of
(24A) and a thickening means (24) comprising an inverting thickener (24B) for inverting the polarity of the output signal of the inverting thickener (24A) and outputting the inverted signal,
The embodiment shown in FIG. 2 is constituted by a pair of half-wave rectifying means (26A) and (26B) for half-wave rectifying and outputting the output signals of the inversion amplifiers (24A) and (24B). It's different.

In the embodiment shown in FIG. 5, the overhead distribution line (1) is connected from the accident point (3).
When the electromagnetic wave emitted by the current traveling wave propagating through the loop antenna (4) is received by the loop antenna (4), the polarity of the first wave of the output voltage of the loop antenna (4) is determined by the traveling direction of the current traveling wave. The time difference signal output means (9) inputs the output signal of the loop antenna (4), determines the direction of the fault point from the polarity of the first wave of the input signal, and has a time difference. Of the two signals, the signal corresponding to the fault point direction of the overhead distribution line is output first. That is, the amplification means (24) inputs the output signal of the loop antenna (4) and outputs two signals having different polarities, and these signals are transmitted by the half-wave rectification means (26A) and (26B). By half-wave rectifying each and outputting, half of the period of the output signal of the loop antenna (4) is inevitably between these two output signals.
When the polarity of the first wave of the output signal of the loop antenna (4) is negative, the half-wave rectifying means (26A) is used. The time difference signal is output before the wave rectifying means (26B). Therefore, this receiving device (8) also operates in the same manner as in the case of the embodiment shown in FIG. 2 and obtains the same effect.

Further, FIG. 6 shows still another embodiment, in which the first output voltage of the loop antenna (4) is the same as the embodiment of FIG.
The direction of the fault point of the overhead distribution line (1) is determined by the polarity of the wave. The amplification means (24) that constitutes the time difference signal output means (9) is the amplification of the embodiment shown in FIG. Instead of the inverting amplifier (24B) of the means (24), a non-inverting amplifier (25) that only enhances the input signal is used, and the input terminal of this non-inverting amplifier (25) is as described above. It differs from the embodiment shown in FIG. 5 in that it is connected to the input terminal of the inverting amplifier (24A) and the signal time difference expanding means (10) is configured as follows.
That is, the signal time difference expanding means (10) in this embodiment
Is a pair of D-flip-flop circuit elements (27A), (27B), each output terminal of which is connected to the other input terminal D.
And a circuit element for generating a reset signal for resetting the D-flip-flop circuit elements (27A) and (27B),
That is, a monostable multivibrator (28) that outputs a pulse signal triggered by the leading edge of the output pulse signal of the monostable multivibrator (16A), the monostable multivibrator (28) and the monostable multivibrator (16). ) OR circuit element (29) that receives both output pulse signals, and a monostable multivibrator (30) that outputs a pulse signal at the trailing edge of the output signal of this OR circuit element (29). It's composed.

The operation of the receiving device (8) in FIG. 6 will be described with reference to the time chart in FIG.

First, the operation in the case of the normal signal input shown in Fig. 7 (a) will be described. The signal is output from the loop antenna (4) as shown in Fig. 7 (b) A _0, and the amplification means (24) Fig. 7 (a) A ₁ , B from the inverting amplifier (24A) and non-inverting amplifier (25)
_As shown in ₁ , signals with different amplitudes and different polarities are output,
Half-wave rectification means (26A) and (26B) perform half-wave rectification and waveform shaping, and the output signals as shown in A ₂ and B ₂ of FIG. 7 are D-flip-flop circuit elements (27A), ( 27B) clock terminal T
Are input respectively. However, the half-wave rectifying means (26
The output signals of A) and (26B) are of the cycle of the output signal of the antenna (4).
Half-wave rectifier means corresponding to the fault point direction at half of the time difference td ₂ (2
Since signal 6A) is output first, the 7 (b) A _4, as shown in B ₄ D- flip-flop circuit elements only (27A) is the first-arrival signal and outputs the self-holding, subsequent D- The flip-flop circuit element (15A) is input to the terminal D and the other circuit element (27B) is interlocked to obtain this circuit element.
Block output from (27B). The D-flip-flop circuit elements (15A) and (15B) are synchronized with the signal output of the half-wave rectifying means (26A) in the same manner as in the embodiment of FIG. It operates by the input signal as shown in Fig. 7 (a) C ₈ output from the AND circuit element (20) of 16), and as shown in Fig. 7 (a) A ₅ and B ₅ , the input signal of terminal D. Self-holds and outputs. On the other hand, the monostable multivibrator (28) inputs the output pulse signal of the monostable multivibrator (16A), outputs a pulse signal of a predetermined time width Tg triggered by the rising edge of the leading edge of this pulse signal, and outputs the OR circuit. A signal such as C _{10 in} FIG. 7 (a) is input to the monostable multivibrator (30) via the element (29). The monostable multivibrator (30) is triggered by the trailing edge of the trailing edge of this input pulse signal and outputs a signal such as C _{11 in} Fig. 7 (a), and the D-flipflop circuit element (27)
A) and (27B) are input to the reset terminals, and these circuit elements (27A) and (27B) are reset. The above O
The R circuit element (29) includes the monostable multivibrator (16
The output pulse signal of A) is also input, but the time width Ti of this pulse signal is ignored because it is shorter than the output pulse signal width Tg of the monostable multivibrator (28) in the case of a normal input signal. Further, by setting the time width Tg of the pulse signal to be longer than the predetermined time width Tc of the output pulse of the monostable multivibrator (17), before resetting the D-flip-flop circuit elements (27A) and (27B). , The D-flip-flop circuit elements (15A) and (15B) are activated (set).

Next, the operation in the case of noise signal input shown in FIG. 7B will be described. Also in this case, from the output signal of the loop antenna (4) to the operation of self-holding the first-arrival signal and blocking the latter-arrival signal output of the D-flip-flop circuit elements (27A) and (27B)
As shown in Fig. (B) A _{0 to} A ₄ , B ₄ , this is the same as in the case of inputting a normal signal.

However, in the case of noise signal input, the signal output from the AND circuit element (20) of the noise signal detection means (16) is changed to C ₈ in FIG. 7 (b) for the same reason as in the embodiment of FIG. Since it is not output as shown, the D-flipflop circuit element (1
5A), (15B) does not operate and does not output a signal as shown in FIG. 7 (b) A _5, B _5. On the other hand, the monostable multivibrator (1
6A), the time length Ti of the output pulse signal is often larger than the time width Tg of the output pulse signal of the monostable multivibrator (28) when a noise signal is input. In this case, the D-flip-flop circuit element is used. (27A) and (27B) will be reset after a time Ti longer than the time width of the noise signal by a predetermined time.

That is, in this embodiment, when the reset timing of the D-flip-flop circuit elements (27A) and (27B) that self-holds and outputs the first-arrival signal and blocks the output of the last-arrival signal, the normal input signal is used. After the predetermined time after the output signal of the above-mentioned circuit element (27A) or (27B) is self-held and output after the D-flip-flop circuit element (15A), (15B) of the latter stage is set and the noise signal is input. This is a predetermined time after the noise signal is input.

Further, in the signal time difference expanding means (10) and the signal fixing means (15) in the embodiment shown in FIG. 6, the D-flip-flop circuit elements (27A), (27B) and (15A), (15B) are used.
It is obvious that a similar effect can be obtained by using a J-flip-flop circuit element instead of. When the negative edge trigger type D-type or J-type flip-flop circuit element is used in the embodiment of FIG. 6, an inverter is provided in the preceding stage for the purpose of inverting the high and low levels of the input signal. The same effect can be obtained by inserting it.

Further, the thickening means (24) consisting of the inverting thickening device (24A) and the non-inverting thickening device (25) shown in FIG. 6 is replaced by the thickening means (24) of the embodiment shown in FIG. On the contrary, even if used for 2
It is clear that the same effect can be obtained by using the thickening means (24) consisting of two inversion thickening devices (24A) and (24B) instead of the thickening means (24) shown in FIG. .

〔The invention's effect〕

As described above, according to the present invention, the noise signal detection means determines whether the input signal received by the antenna is a regular signal or a noise signal, and if it is a regular signal, outputs a signal corresponding to this signal and outputs the signal. The fixing means is triggered, and at that time, the first-come-first-served signal indicating the direction of the accident point, which is input from the signal time difference expanding means in the preceding stage, is self-held and output, but if it is a noise signal, the corresponding signal, that is, noise Since the detection signal is output, the trigger signal of the signal fixing means is not output, and the signal fixing means is configured not to operate, it is possible to prevent an erroneous display of the device due to the input of the noise signal and to input the noise signal. There is an effect that it can be detected.

[Brief description of drawings]

FIG. 1 is an explanatory view for explaining the concept of the receiver for accident point search according to the present invention, and FIG. 2 is a block diagram showing an embodiment of the receiver for accident point search according to the present invention, FIGS. 3 and 4. Is a time chart showing the operation of the input / output terminal of the receiving device shown in FIG. 2, and FIGS. 5 and 6 are block diagrams of the receiving device for detecting an accident point showing another different embodiment, respectively.
FIG. 8 is a time chart showing the operation of the input / output terminals of the receiving device shown in FIG. 6, and FIG. 8 is a block diagram showing the conventional receiving device. In the figure, (1) is an overhead distribution line, (2) is a high-voltage pulse applying means (voltage-applying device), (3) is a ground fault equipment, (4), (4A), (4B)
Is a loop antenna, (8) is a receiving device, (9) is a time difference signal output means, (10) is a signal time difference expanding means, (15) is a signal fixing means, and (17) is a noise signal detecting means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. An antenna for receiving an electromagnetic wave generated by a current traveling wave from an accident point of an overhead distribution line, a time difference signal output means for outputting a time difference signal by an output signal of the antenna, and a time difference between output signals of the time difference signal output means. A signal which expands and outputs a signal over a predetermined time difference, the output signal of the time difference signal output means is input, and it is determined whether this input signal is noise or a normal signal, and a signal corresponding to noise or a normal signal is obtained. A noise signal detecting means for outputting a corresponding signal, and a signal fixing means for triggering by an output signal corresponding to a normal signal of the noise signal detecting means and for self-holding and outputting the first-arrival signal output from the signal time difference expanding circuit. A receiver for detecting an accident point, comprising: 2. A first monostable multivibrator with a retrigger function, wherein the noise signal detection means is triggered by a voltage change of an input signal and outputs a pulse signal having a predetermined time longer than the time length of the input signal, This monostable multivibrator or a second monostable multivibrator which outputs a pulse signal having a predetermined time width shorter than the time difference of the output signal of the signal time difference expanding means by the voltage change of the leading edge of the output pulse signal of the signal time difference expanding means. A third monostable multivibrator that outputs a pulse signal according to a voltage change at a trailing edge of an output pulse signal of the second monostable multivibrator, an output pulse signal of the third monostable multivibrator, and the first Input the output pulse signal of the monostable multivibrator of and output the signal corresponding to the noise input The first AND circuit, the output pulse signal of the third monostable multivibrator, and the inverted signal of the output pulse signal of the first monostable multivibrator are input to output a signal corresponding to the normal signal. AN
Claim 1 characterized in that it comprises a D circuit.
Receiving device for accident point search described in paragraph.