JPS6139973Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for detecting ground fault points in overhead distribution lines (mainly overhead high-voltage distribution lines).

A conventional fault point detection device in which a transmitter intermittently sends out high-voltage pulses to the distribution line, while a worker carries a receiver and searches while moving along the distribution line. In this case, if a ground fault is caused by temporary contact of an animal such as a snake with a power distribution line, there is no need to go and investigate as the fault has already disappeared. However, it had the drawback of having to carefully search for the accident point, and end up wasting time without finding the accident point. In addition, in cases where ground faults occur due to trees, etc. occasionally coming into contact with power distribution lines, the receiver may not be aware of this and proceed with the search solely by relying on the receiver, causing the receiver to detect the signal. However, it also had the disadvantage that in some cases it did not detect the problem, resulting in the system having to repeatedly go back and forth along the distribution line without being able to locate the fault point.

Therefore, the present invention is designed to eliminate the above-mentioned drawbacks, and it is possible to know in advance whether or not there is a ground fault point on the distribution line before conducting exploration work along the distribution line, and furthermore, it is possible to know in advance whether or not there is a ground fault point on the distribution line. To provide an accident point detection device capable of estimating the type of ground fault accident in advance if there is one, and expediting subsequent work.

Examples of the present application will be described below. Figure 1 shows the principle of accident point exploration. In this figure, 100 indicates the ground, and 101 indicates an overhead high voltage distribution line. It is assumed that a point indicated by the reference numeral 102 on the distribution line of the distribution line 101 is an accident point of a ground fault. As is well known, there are various types of accidents such as damage to various equipment, cracks in insulators, and damage. In this distribution line, a high voltage pulse transmitter 1
03 is connected as shown in the figure, and a high voltage pulse is sent to the distribution line 101. Then, the current is arrow 104
The flow is as shown in . For this reason, the receiver 105
When moving along the above distribution line 101,
Before and after the accident point 102, the reception level changes as shown in (A). Therefore, by observing this change, the accident point can be discovered.

Next, the investigation work for the accident point will be explained in detail with further reference to FIGS. 2 to 9 of the drawings.

First, an overview of the work will be explained.

(A) First, take the transmitter and receiver and go to the substation where the failure is predicted to occur.

(B) Next, open the section switch to bring the section (indicated by reference numeral 106 in FIG. 1) where a failure is predicted to be out of power at the substation.

(C) Next, connect the transmitter 103. For this connection, first ground the ground terminal. This grounding means is the case 103' of the transmitter 103.
Connect the connector 5 of the main grounding lead wire 4 to the main grounding connector 2 attached to the
Further, the connector 8 connected to the auxiliary grounding lead wire 7 is connected to the auxiliary grounding connector 3 attached to the case 103' of the transmitter 103. On the other hand, the main grounding rod 6 and the auxiliary grounding rod 9 are driven into the ground while being separated from each other. Thereafter, the clip 4a of the main grounding lead wire 4 and the clip 7a of the auxiliary grounding lead wire 7 are connected to the grounding rods 6 and 9, respectively. Next, the high voltage output terminal 1 attached to the case 103' of the transmitter 103 is connected to all phases of the three-phase distribution line 101 in the power outage state using connection wires.

Next, the power terminal of the transmitter 103 is connected to a power source. For this connection, transmitter 1
Since the 03 case 103' is provided with an AC 100V input terminal 10 and a DC 12V input terminal 11, it is sufficient to select the power source that is available depending on the work place. Depending on the selection of this power source, the AC/DC switching switch SW ₁ is switched.

(D) Operation (1) First, close power switch SW ₂ to supply power to each circuit.

(2) Next, close charging pushbutton switch PB ₂ . Then, each circuit operates as described later, and a high voltage is stored in the high voltage capacitor _C1 .

(3) Next, close the transmission pushbutton switch PB ₃ . Then, the above high voltage capacitor C ₁
The high voltage stored in is sent out from the high voltage output terminal 1 to the distribution line 101.

(4) When high voltage is sent to the distribution line 101 as described above, the ground fault indicator meter _M2 displays the presence or absence of a fault point and, if there is a fault point, the magnitude of the fault.

(5) If it is confirmed that there is a fault point based on the meter _M2 as described above, then carry a receiver and move along the distribution line where the high voltage is sent out, and search for the fault point. Do the following.

(6) When the investigation of the accident point is completed as described above, open the stop push button switch PB ₁ and also open the power switch SW ₂ .

(E) Once the above operations are completed, disconnect the power supply, disconnect the ground connection, and disconnect the high voltage side.

(F) Once the exploration has been completed as described above, the faulty part will be repaired as is well known, and then the opened section switch will be closed.

Next, each of the above operations will be explained in more detail.

(D)-(1) When the power switch SW ₂ is closed, the AC 100V power supply current from the input terminal 10 or the DC 12V power input from the input terminal 11 (for example, power from a car battery) is transferred to the inverter 12. The AC 100V power supply current obtained by conversion is
SW ₁ , power switch SW ₂ , fuse F (5
A). Then, the power indicator lamp PL ₁ and the high voltage stop lamp PL ₂ light up, respectively. A part of the input power supply current is also supplied to the ground confirmation circuit 14.

(D)-(2) Next, when charging pushbutton switch PB ₂ is closed (time point A in the time chart in Figure 5), the above power supply current flows to the ground confirmation circuit 14.
After passing through as described below, the signal is sent to each circuit element via the stop pushbutton switch _PB1 and the charging pushbutton switch _PB2 , both of which are in the closed state.

Then, each circuit element operates as shown in the time chart of FIG. That is, when the charging pushbutton switch _PB2 is closed as described above, the relay _R1 is energized via the diode _D5 . Then, relay contact R ₁ − of relay R _1
1 is closed to form a self-holding circuit. In addition, the relay contacts _R1-2 are switched, the high voltage stop lamp _PL2 is turned off, and the high _pressure air switch operating solenoid (first solenoid) _L1 is operated. Then, the two normally closed contacts L ₁ - ₁ of the high pressure air switch in the high voltage generation circuit 15,
_L1-2 open _respectively .

Also, when the charging pushbutton switch PB ₂ is closed, the relay contact R ₃ − of the relay R ₃ described later
Power supply current is supplied to the high voltage adjustment slider SD through _1b , and this slider SD
Power supply current is supplied to the primary coil of the step-up transformer Tr ₁ (a neon transformer is used as an example) through the transformer Tr 1 . Then, a high voltage is generated on the secondary side of the step-up transformer _Tr1 .
This high voltage (for example, 15KV) is converted into direct current through a high-voltage rectifier diode D ₁ and charged to a high-voltage capacitor C ₁ (for example, 2 μF 20KV). The voltage charged in the high voltage capacitor C ₁ is displayed by the charging voltage meter M ₁ via resistors r ₁ , r ₂ , r ₃ and capacitor C ₂ . Therefore, while watching this charging voltage meter _M1 , adjust the high voltage adjustment slider SD so that a predetermined high voltage is charged to the high voltage capacitor _C1 .

(D)-(3) Next, close the transmission pushbutton switch _PB3 (point B in FIG. 5). Then, relay _R2 is energized via diode _D6 , and relay _R2 operates. Relay contact _R2-1 closes due to the operation of relay _R2 , and _the first timer _T1
is supplied with power, and timer _T1 starts operating. Also, the high voltage application indicator lamp PL ₄ lights up. When the timer _T1 starts operating and a certain period of time (5.5 seconds in this example) has elapsed, _the timer contact _T1-1 closes for a short time (0.5 seconds in this example). _When timer contact _T1-1 closes, relay _R3 operates. Then, the relay contact _R3-1a closes, and _the AC power is rectified by the solenoid operating rectifier 17, smoothed by the smoothing capacitor _C3 , and then the high-pressure air switch operating solenoid (second solenoid)
Added to L ₂ . Then, the high-pressure air switch operating solenoid _L2 is activated, and _the normally open contact _L2-1 of the high-pressure air switch is closed. Then, the high voltage stored in the high voltage capacitor C ₁ is pulsed from the high voltage output terminal 1 to the distribution line via the limiting resistor (2.5KΩ) 18 and the contact L ₂ - ₁ , that is, as a high voltage. Sent out as voltage pulses.

At the same time _, relay contact _R3-2 is closed and power is supplied to the second timer _T2 . Also, in this state, the third timer T ₃ in the closed state
Power is supplied to the _{relay R4} through the timer contact _T3-1 and the diode _D7 , and this relay _R4 operates, and even after _the relay contact _R4-1 closes and _R3-2 opens _. Self-maintained. When the second timer _T2 starts operating and a certain period of time (2 seconds in this example) has elapsed, the second timer T2 starts operating.
The first contact _{T2-1 of} timer _T2 closes. Then, the third timer _T3 for reset also starts operating. A certain period of time after the third timer T ₃ starts operating (in this example, 2.2 seconds, that is, 4.2 seconds after the second timer T ₂ starts operating)
Once the time has elapsed, timer contact T _{3 -1} of third timer T ₃ momentarily opens and relay R ₄ is released. This opens relay contact R ₄ - ₁ , which opens timer T ₂ and its timer contact T _2
-1 , and the third timer _T3 returns again. Note that these second and third timers T ₂ and T ₃
The operation of the circuit and its related circuits is to intermittently open and close contact T ₂ - ₂ in the ground fault indicating circuit 16, which will be described later.

After that, as shown in the time chart, the timer contacts T ₁ - ₁ of the first timer T ₁ close for 0.5 seconds at 6 second intervals, so the same operation as above is repeated every time the timer contacts T ₁ - ₁ close. Then, high voltage pulses are sent out one after another from the high voltage output terminal 1 toward the power distribution line.

(D)-(4) As mentioned above, when a high voltage pulse is sent out from the high voltage output terminal 1 to the distribution line 101 and there is a ground fault point (fault point 102) in the middle of the sent out distribution line 101, The above-mentioned high-voltage pulse passes through the ground fault resistance through the following path, namely, the high-voltage capacitor C ₁ , the limiting resistor 18, and the normally open contact of the high-pressure air switch, as shown in Figure 6. _L2-1 , high voltage output terminal 1, distribution line 101, ground fault resistance Rx, earth between the ground fault point and transmitter installation point, ground rod 6 _, grounding lead wire 4, connectors 5, 2, transmission Ground circuit 19 of machine 103, resistor 2 for ground fault detection
0, flows through the high voltage capacitor _C1 path. In this case, when the ground fault resistance Rx is OΩ, that is, a complete ground fault, a current of 6 A flows through the path as described above. (In addition, this 6A is the current limiting resistor 18 when the charging voltage of the high voltage capacitor C ₁ is 15KV.
It is the value divided by the resistance value of 2.5KΩ. ) When the above-mentioned current flows, a voltage of 30V, for example, is generated across the ground fault detection resistor 20 (5Ω, for example). This voltage is charged to the hold capacitor _C4 via the relay contact _R2-2 (this contact is closed because the relay _R2 is operating as described above) and _the diode _D3 . The electric charge charged in the capacitor C ₄ flows to the ground fault indicator meter M ₂ via the resistors r ₄ and r ₅ . This causes the meter _M2 to indicate that the above-mentioned ground fault current has flowed. Furthermore, the ground fault resistance as above is OΩ.
In the case of
Sensitivity of earth fault indicator meter _M2 (e.g. 100μ
A) The values of resistors r ₄ and r ₅ (both together)
100KΩ) is selected.

In this way, when 2 seconds have passed since the earth fault indicator meter _M2 indicates that the earth fault current has flowed,
As described above, the timer contact _T2-2 closes due to the operation _of timer _T2 . As a result, the charge stored in capacitor C ₄ is momentarily discharged, and the needle of meter M ₂ returns to its starting point. Therefore, as described above, each time high voltage pulses are sent to the distribution line 101 at 6 second intervals, the ground fault indicator meter _M2 indicates for 2 seconds that there is a ground fault point and that a ground fault current is flowing.

Next, a case will be described in which there is a ground fault point, but the ground fault resistance Rx is relatively large (for example, 5KΩ). In this case, the current flowing in the above path is 15KV divided by 7.5KΩ, which is the sum of 25KΩ and 5KΩ, or 2A. Therefore, a voltage of 10V is generated across the ground fault detection resistor 20. Accordingly, a corresponding charge is stored in capacitor _C4 . Therefore, in this case, the ground fault indicator meter _M2 indicates the intermediate point b as shown in FIG.

Next, if there is no ground fault point, the ground fault resistance is infinite, so no current will flow through the path described above. Therefore, no voltage appears across the ground fault detection resistor 20 either. As a result, the ground fault indicator meter _M2 continues to indicate the starting point.
In reality, there is a ground capacitance of the distribution line,
Furthermore, when it rains, the surface resistance of utility poles and insulators decreases, so a small amount of current flows through these as well through the above-mentioned path. The flowing current generates a voltage across the ground fault detection resistor 20. However, due to the above-mentioned causes, the current flowing through the above path is extremely small, and therefore the voltage generated across the ground fault detection resistor 20 is also extremely small. Therefore earth fault indicator meter M ₂
The deflection of the pointer is also extremely small (at most the extent shown by c in Fig. 7). Therefore, in this case, the distribution line is considered to be healthy.

(D)-(5) Exploration of the fault point using the receiver is performed as follows. That is, a worker carries the receiver 105 and moves along the power distribution line. receiver 10
For example, a configuration as shown in FIG. 8 is used as 5. When searching for an accident point using this receiver, the following operations are performed in the receiver.

(1) Before passing the fault point High voltage pulses are sent from the transmitter to the distribution line 101 at 6 second intervals as shown in a in FIG. 9. This signal is then detected by antenna 31 in receiver 105 as shown in FIG. 9b. This detected signal is amplified by an amplifier 32 as shown in c, and further rectified by a rectifier 33 as shown in d. This rectified signal is differentiated by a differentiator 34 and becomes a signal as shown in e. This signal is further rectified by a rectifier 35 to become a signal indicated by f, and a signal indicated by g is added to a meter 36. Therefore, the meter 36 intermittently swings significantly each time the high voltage pulse is sent to the power distribution line.

On the other hand, the output signal of the amplifier 32 is sent to the audio monitor circuit 37.
7 outputs a signal as indicated by h. This signal is rectified by a rectifier 38 as indicated by 1, and further differentiated by a differentiator 39 as indicated by j, thereby intermittently activating the audio alarm 40 as indicated by k. Therefore, the audio alarm device 40 intermittently emits an alarm sound such as "boo".

(2) When passing the accident point Beyond the accident point, almost no signal from the transmitter comes to the distribution line, so the receiver 105 is almost unable to receive the signal. Or the reception level becomes extremely low. Therefore, the deflection of the meter 36 is also extremely small (the deflection is reduced by more than half). Also, audio alarm 4
0 will also no longer issue an alarm.

(D)-(6) When stop pushbutton switch PB ₁ is opened, power supply current is no longer supplied to relay R 1 and relay _{R 1 returns} to its normal state. Then, the relay contact R ₁ - ₂ returns to the state shown in the figure, and the high pressure air switch operating solenoid L ₁ also returns to its original state. Therefore, the normally closed contacts L ₁ - ₁ and L ₁ - ₂ of the high pressure air switch in the high voltage generation circuit 15 are respectively closed as shown. Then, the charge stored in the high voltage capacitor C ₁ is transferred to the limiting resistor 1
8. Discharge occurs through the path of contact L ₁ - ₁ and discharge resistor 21 . In addition, the charge remaining on the distribution line 101 is also transferred to the high voltage output terminal 1, contact _L1-2 , _discharge resistor 21, grounding circuit 19, connector 2,
5. Discharge occurs through the path of the main grounding rod 6. Therefore, even if the user touches the high voltage output terminal 1 to disconnect the connection after completing the measurement operation as described above, or works on the power distribution line, a discharge accident can be prevented.

Next, the ground confirmation circuit 14 will be explained.

When the main earthing rod 6 and the auxiliary earthing rod 9 are completely grounded, and the connection between the earthing rods 6 and 9 and the main earthing connector 2 and the auxiliary earthing connector 3 is complete, the following occurs. An action is taken.

When the power switch SW ₂ is turned on, a voltage is applied to the primary coil Tr _{2 a} of the first insulating transformer Tr 2 (a 100 V to 10 V transformer is used as an example). Then, a voltage appears in the secondary coil Tr ₂ b of the transformer Tr ₂ , and the following circuit, that is, the secondary coil
Tr ₂ b, terminal 3c of auxiliary grounding connector 3, terminal 8c of connector 8, auxiliary grounding lead wire 7, clip 7a, auxiliary grounding rod 9, main grounding rod 6, clip 4a, main grounding lead wire 4, connector 5 Terminal 5c of connector 2, terminal 2c of connector 2, primary side Tr _{3a of second insulation transformer Tr 3 to} insulation transformer
Current flows in the circuit of Tr ₂ b on the secondary side of Tr ₂ . Then, a voltage is induced in the secondary side Tr ₃ b of the insulating transformer Tr ₃ , and a signal is applied between the gate and cathode of the thyristor SCR ₁ . This establishes conduction between the anode and cathode of thyristor _SCR1 . Then relay _R5 operates. Due to the operation of relay _R5 , its _{contact R5-1}
closes. Then, the current from the power switch SW ₂ is applied to the terminal 3b of the auxiliary grounding connector 3, the terminal 8b of the connector 8, the terminal 8a of the connector 8, the terminal 3a of the connector 3, the terminal 2b of the main grounding connector 2, and the terminal of the connector 5. 5b, the terminal 5a of the connector 5, the terminal 2a _of the connector 2, and the relay contact _R5-1 .

In order to perform such an operation, the main grounding rod 6 and the auxiliary grounding rod 9 must be in perfect contact with the ground (the driving interval between these grounding rods 6 and 9 must be, for example, 0.5 to 1.
m. ), it is desirable that the grounding resistance between the grounding rods 6 and 9 is, for example, 1KΩ or less.

Furthermore, since a DC relay is used as _the relay R ₅ , a capacitor C ₅ is connected in parallel to it, and the relay R ₅ and capacitor C ₅ are A protective diode _D2 is connected to prevent destruction.

Furthermore, whether the grounding is complete and energization is being carried out reliably can be determined by the lighting of the grounding confirmation display lamp _PL5 connected in parallel with the relay _R5 .

Also connected to various parts of this ground confirmation circuit 14.
ZNR is a surge generator used to prevent insulation transformers Tr ₃ and Tr ₂ from being destroyed due to the potential difference between the 100V AC second-class ground used as a power source and the ground of the case of this transmitter. It is an absorber.

In the above case, if either the main grounding rod 6 or the auxiliary grounding rod 9 is not securely grounded, the grounding resistance between the two grounding rods 6 and 9 will be larger than the predetermined value. . Then, the current flowing through the primary side Tr ₃ a of the insulating transformer Tr ₃ becomes smaller, and the voltage appearing on its secondary side Tr ₃ b also becomes smaller. Thyristor SCR therefore does not conduct. Therefore, relay _R5 also does not operate and relay contact _{R5-1 remains} open. In this case, relay contact R _5-1 remains open, i.e. if the installation is incomplete and high voltages may be induced in the transmitter case and pose _a danger to personnel. Therefore, no current flows to the charging push button side. Therefore, high pressure as described above is not generated.

The above also applies to the connection between the main grounding connector 2 and the connector 5, or the connection between the auxiliary grounding connector 3.
The same applies when the connection between the connector 8 and the connector 8 is incomplete.

Furthermore, if the grounding lead wire comes off from the grounding rod while the transmitter is in use, or if connector 5 or 8 comes off from connector 2 or 3, the relay contact R ₅ - ₁ opens, cutting off the current supply.

That is, as is clear from the circuit diagram, the thyristor
An alternating current signal is used as the gate signal for SCR ₁ . Therefore, if the grounding lead wires 4 and 7 are broken or the clips come off and the grounding becomes incomplete, the signal to the gate of thyristor SCR ₁ is immediately cut off and the signal to the gate of thyristor SCR ₁ is interrupted. is OFF
This is because.

Next, FIG. 10 shows an embodiment in which the configuration of the transmitter for detecting the accident point is simplified. In the figure, 61 is an intermittent operating circuit that intermittently generates an output signal and connects the solenoid L ₂ e and the timer 6 described below.
2 is set to operate. As this circuit, in addition to the circuit composed of the timer _T1 and related circuit elements in the previous embodiment, other circuits that generate output signals intermittently may be used. Reference numeral 62 denotes a timer, which is configured to produce an output and close the timer contact 63 when a predetermined period of time has elapsed after the input of the signal from the circuit. As this timer, other than the circuit constituted by the timer timer _T2 and related circuit elements, other circuits that operate as described above may be used.

As described above, in this invention, high voltage pulses are sent out intermittently to the distribution line 101 one after another, so when searching for a fault point on the distribution line 101, the high voltage pulses are By sending the signal out onto the power line, the receiver can be moved along the power distribution line, as is well known, and the fault point can be easily found.

Moreover, in the case of the device of the present invention, a high voltage pulse is sent to the distribution line 101, and when the current due to the high voltage pulse flows to the ground via the ground fault resistance Rx at the ground fault point, the current is connected to the ground fault point. Detection resistor 20
Since the ground fault indicator meter M ₂ is caused to swing according to the magnitude of the current, when attempting to locate the ground fault point of the distribution line 101 as described above, the above meter M ₂ One of the features of this system is that it is possible to instantly determine whether or not it is necessary to sequentially explore various parts of a long power distribution line as described above, just by looking at the fluctuations of the system, while remaining in the location where the equipment is installed. . This has a revolutionary effect in preventing unnecessary work such as going out of the way even though there is no fault point on the distribution line.

Moreover, since the meter M ₂ is made to swing according to the magnitude of the current, if it is determined that there is a fault point based on the swing of the meter M ₂ , the magnitude of the swing of the meter M ₂ It has the advantage of being able to infer the type of ground fault at the same time. This makes it possible to plan in advance how best to carry out future exploration, or how to carry out subsequent accident recovery work, and to expedite the subsequent work. It has a big effect. To reiterate the above point in more detail, the device of the present invention can repeatedly send high voltage pulses to the distribution line, and at the same time, it can send a meter M ₂ that swings due to the current flowing due to the pulse. To prepare for the problem, after arriving at one end of the section where the fault point is to be detected and connecting this device, wait for a while before going out to investigate the fault point sequentially along the distribution line in the fault section.
By repeatedly sending high-voltage pulses to the distribution line and observing how the meter _M2 swings, we can determine whether or not it is necessary to go out to investigate the fault point, and if so, what to do. It has the advantage of letting you know before you go out whether you should go out or not. (1) Even if pulses are repeatedly sent to the distribution line, the meter will not work.
If M ₂ never swings, it can be assumed that, for example, a bird or a snake has touched the power line temporarily and has already left the line. Therefore, in this case, it can be determined that it is unnecessary to go out of the way to explore, and there is an effect that the waste of time for such exploration can be omitted.

(2) If meter _M2 swings or does not swing, it is assumed that trees are swaying in the wind and touch the power lines only in strong winds, or that kites tangled in the power lines occasionally touch the ground wire. be able to.
Also, if the insulator swings or does not swing depending on the strength of the rain, it can be inferred that bridging occurs in the cracks in the insulator only during heavy rain, causing a ground fault. Therefore, in these cases, it can be determined that it is necessary to conduct an exploration along the distribution lines, and the person who goes out for the exploration is advised to carefully visually check the distribution lines, obstacles around them, and insulators that support the wiring. It has the feature of encouraging exploration to proceed.

(3) Meter _M2 is touched every time, but if the way it swings each time is that it swings gradually up to the middle and then suddenly stops, it can be inferred that a gap ground fault has occurred in the insulator. Therefore, when it is determined that exploration is necessary and the user goes out to explore, it is possible to move while paying attention to the instructions from the receiver, and to move in areas where there are insulators while paying attention to the insulators.

(4) If the meter _M2 swings out every time, it can be inferred that a complete ground fault has occurred. In this case, it can be immediately determined that an exploration is required, and the exploration method also has the advantage of allowing rapid exploration by car, for example, while paying attention only to instructions from the receiver.

In this way, the device of the present invention has a great practical effect of making it possible to judge in advance whether or not it is necessary to go on an exploration trip and the method of exploration that is appropriate for the type of accident before going on an exploration trip. .

Furthermore, in the present invention, since a hold capacitor _C4 is attached to the meter _M2 , even if the current flowing due to the high voltage pulse is extremely short, the meter _M2 will not swing. It also has the effect of lengthening the time and making it easier to see the swing of the meter _M2 .

Moreover, as mentioned above, high voltage pulses are sent out one after another intermittently, and each time the meter _M2 sends out a high voltage pulse and gives an instruction, both ends are short-circuited to recover, and the next pulse is sent out. When the accident occurs, instructions are given again from the zero state, so the worker can see not only the maximum deflection of meter _M2 but also the average deflection each time. This also has the effect of making inferences more accurate. Furthermore, in the case of the fault point detection device of the present invention, if the earth fault indicator meter _M2 swings due to the sending of high voltage pulses as described above, the swing is held, and then the swing is restored after a certain period of time has elapsed. Even if the earth fault indicator meter _M2 is configured to perform
The deflection of the meter is held by a holding capacitor C ₄ connected in parallel to the timer contact T ₂ − connected in parallel to the capacitor C ₄ .
₂ short-circuits the capacitor C ₄ to discharge its charge and restore the deflection of the meter M _2. Therefore, the structure is simple, has few parts, and is inexpensive. As a result, the device can be provided at a low price. be.

Furthermore, even if the above-mentioned operation is repeated each time the high-voltage pulse is sent out, when performing the repeated operation,
Each time an actuation signal is intermittently output from one intermittent actuation circuit, (a) the solenoid _L2 is actuated to close _the solenoid contact _L2-1 and send out a high voltage pulse. (b) By activating the timer _T2 , _the timer contact _T2-2 is closed after a certain period of time and the meter _M2 is restored, so that the sending of high voltage pulses and the restoration of the meter _M2 can be accurately performed. It has the advantage of being able to be repeated at specific timings. This has the effect of increasing the accuracy of the deflection of the meter _M2 each time a high voltage pulse is sent out, and therefore making it possible to estimate the type of the ground fault with high reliability.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and Fig. 1 shows an overview of fault point detection, Fig. 2 shows a circuit diagram of a transmitter, Fig. 3 shows a grounding system, and Fig. 4 shows a connector. Figure 5 is a time chart, Figure 6 is a diagram showing the circuit through which earth fault current flows, Figure 7 is an explanation diagram of instructions for the earth fault indicator meter, Figure 8 is a block diagram of the receiver. , FIG. 9 is an operating waveform diagram of the receiver, and FIG. 10 is a diagram showing a different embodiment. 100...Earth, 101...Power line, 103'
...Case, 15...High voltage generation circuit.

Claims (1)

[Scope of utility model registration request] The case is equipped with a high voltage generation circuit, a high voltage output terminal that can be connected to a power distribution line, and a ground terminal that can be grounded to the earth, and the high voltage side of the high voltage generation circuit is The ground side of the high voltage generation circuit is connected to the high voltage output terminal, and the ground side of the high voltage generation circuit is connected to the ground terminal. A solenoid contact is provided, and a ground fault detection resistor is provided in the connection circuit between the ground side of the high voltage generation circuit and the ground terminal, and a diode is provided at both ends of the ground fault detection resistor. A hold capacitor is connected through the capacitor, and a ground fault indicator meter and a timer contact are connected in parallel to both ends of the capacitor, and on the other hand, an intermittent operation circuit is provided that outputs an operation signal intermittently. and a solenoid for activating the solenoid contact and a timer for activating the timer contact are connected to the output end of the intermittent operation circuit, and the timer, after inputting a signal, The timer contact is configured to temporarily close when a certain period of time shorter than the time interval of the output signal of the intermittent operation circuit has elapsed, and the solenoid contact is closed by the solenoid when the operation signal is output from the intermittent operation circuit. A high-voltage pulse is sent out to the distribution line, and when the predetermined period of time has elapsed, a timer contact closes to short-circuit the hold capacitor.