JP2636165B2 - Bypass connection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bypass connection device and, more particularly, to a low-voltage meter such as a watt-hour meter, which is used in an exchanging work to replace the low-voltage meter in an uninterrupted state with the completion of verification. The present invention relates to a bypass connection device for checking a connection state of a bypass line and an insulated wire during construction.

[0002]

2. Description of the Related Art For example, in the replacement work associated with the expiration of verification of a low-voltage meter such as a watt-hour meter, it has conventionally been difficult to perform replacement while supplying power to a load from a power supply.
It was common practice during blackouts. Replacement work in this power outage state is particularly inconvenient for power consumers who are not away, for example, time delay of electric clocks and timers,
This will cause inconvenience such as the loss of computer data.

Therefore, in recent years, as shown in FIG. 6, connection wires A _{1S to} A _3S and A _{1L to} A _1S on the power source S side and the load L side of the watt hour meter 1 so that replacement work can be performed in an uninterrupted state. the bypass line B ₁ .about.B ₃ connected between _3L, the bypass lines B ₁ ~
While supplying power from a power source S to the load L with a detour by B _3, approach to replace the energy meter 1 uninterruptible state is employed.

Here, the power supply S side of the watt-hour meter 1 is
Connection wire A on load L side_1S~ A_3S, A _1L~ A_3LIs the core wire
It is usually insulated wire with insulation coating.
The bypass line B₁~ B_ThreeAt both ends of the connecting wire A_1S~
A_3S, A_1L~ A_3L[Hereinafter referred to as insulated wire]
Dedicated to cut into the wire and electrically connect to the core wire
A tool 2 is provided.

[0005]

By the way, as described above,
In the case of single-phase three-wire or three-phase three-wire watt hour meter 1,
During replacement work during a power outage, the power meter 1
Insulated wire A_1S~ A_3S, A_1L~ A_3LIs the power supply S side and the load L
There will be three lines on each side. Therefore, the bypass line
B₁~ B_ThreeAlso requires three lines, and the bypass line
B₁~ B_ThreeTo insulated wire A_1S~ A_3S, A_1L~ A_3LConnect to
Insulated wire A on power supply S side_1S~ A_3SAnd this
And the corresponding insulated wire A on the load L side_1L~ A_3LBetween the two
Ipass line B ₁~ B_ThreeMust be connected without misconnection
No.

Accordingly, the operator can operate the bypass lines B _{1 to} B ₃
Inadvertently connecting and short-circuiting, there is a danger that the watt-hour meter 1 explodes due to the heat generated by the large current due to the instantaneous flow of a large current through the watt-hour meter 1, causing serious injury to the operator. is there. Therefore, the operator must carefully perform the replacement work, and there is a problem that the workability is extremely reduced.

Further, as described above, the insulated wires A _1S to
A _3S, A _1L order to A _3L is obtained by insulating coating treatment to the core wire, insulated wire A _1S to A _3S, bypass line B to A _1L to A _3L
When connecting _{1 to} B ₃ , bypass lines B _{1 to} B ₃
Special tools 2 at both ends of the insulated wires A _{1S to} A _3S , A _1L
ＡA _3L must be cut into the covering and electrically connected to the core wire. As a result, the special tool 2 does not reach the core wire due to insufficient bite into the insulated wires A _{1S to} A _3S , A _{1L to} A _3L , and the bypass wires B _{1 to} B ₃ are electrically connected to the core wire. May occur.

Also, the above-mentioned bypass line B₁~ B_ThreeContact
At the time of continuation, the special tools 2 at both ends_1S~
A_3S, A_1L~ A_3LEven if it is securely connected to
Prior to removal of watt-hour meter 1, temporarily
Wire A_1S~ A_3S, A_1L~ A_3LFrom the watt hour meter 1
Without bypass line B₁~ B_ThreeWith insulated wire A_1S~
A _3S, A_1L~ A_3LWhen the tool is pulled out,
Stressed bypass line B₁~ B_ThreeInsulated wire A
_1S~ A_3S, A_1L~ A_3LPossibility of poor connection with
is there.

As described above, when the bypass lines B _{1 to} B ₃ are connected and before the watt hour meter 1 is removed, the bypass line B _{1 is connected.}
If there is a poor connection .about.B _3, so that the power failure at the moment of removal in order to replace the energy meter 1. In particular, single phase 3
In the case of the wire system, if the insulated wires A _{1S to} A _3S , A _{1L to} A _3L have a poor connection to the neutral wire, a double voltage will be applied to the load and the electric equipment used by the user. In the case of a three-phase three-wire system, an open phase may occur. The bypass line B ₁ .about.B ₃ is insulated wire A _1S to A _3S, whether are securely connected to the A _1L to A _3L, worker because it was impossible to confirm visually, worker It had to rely on sensory things, and the workers required some skill.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a bypass connection device capable of checking the connection state of a bypass line and an insulated wire beforehand. .

[0011]

As a technical means for achieving the above object, the present invention relates to a plurality of pairs of insulated electric wires connected between a power supply side and a load side of a low-voltage meter and in a charged state. a plurality of bypass lines which are temporarily connected between the pair
Check whether the cable is properly connected between the corresponding insulated wires.
A misconnection detection circuit that detects whether a line voltage is generated between each bypass line on the power supply side and the load side, and a predetermined current flows through the insulated wire through the bypass line. Current detection circuit that detects whether or not the current is connected to the load side of the insulated wire, and a bypass line is connected between the power supply side and the load side based on the detection output of the incorrect connection detection circuit or the current detection circuit. And a control circuit for opening and closing a relay contact to be connected.

Further, the present invention provides a power supply circuit for driving the control circuit at a predetermined voltage and a control circuit thereof. It is desirable to provide a disconnection prevention circuit that opens the relay contact by disconnecting from the insulated wire and cuts off the drive voltage from the power supply circuit.

[0013]

In the bypass connection device according to the present invention, when connecting the bypass line between the insulated wires on the power supply side and the load side of the low-voltage gauge, whether the power supply side and the load side are correctly connected to the corresponding insulated wires. Is detected by the incorrect connection detection circuit. That is, in the erroneous connection detection circuit, the connection state of the bypass line is detected based on whether a line voltage is generated between the bypass lines.

When the low-voltage gauge is removed for replacement after the completion of the bypass connection, a current detection circuit detects whether or not the bypass line has a poor connection with the insulated wire. That is, in this current detection circuit, the current transformer connected to the load side of the insulated wire detects the connection state of the bypass wire based on whether or not a predetermined current is flowing through the insulated wire via the bypass wire. .

The connection state of the bypass line is recognized by the control circuit based on the detection outputs of the erroneous connection detection circuit and the current detection circuit. That is, the improper connection detection circuit determines the suitability of the work of connecting the bypass line to the insulated wire, and the current detection circuit determines the suitability of the connection state of the bypass line in the work of removing the low-voltage gauge.

Further, even if the power switch is forgotten to be turned off after the replacement of the low-voltage gauge, the forgotten-off prevention circuit provides
When the bypass line is disconnected from the insulated wire, the relay contact is opened and the drive voltage from the power supply circuit is cut off. Can be prevented.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In the following, a single-phase three-wire system or a three-phase three-wire system shown in FIG.
An embodiment applied to the linear watt-hour meter 1 will be described in detail, and the same parts as those in FIG.

The bypass connection device 3 is, as shown in FIG.
Connected between the power supply S side and the load L side of
Pair of Insulated Wires A in Electrical State_1SAnd A_1L, A_2SWhen
A_2L, A _3SAnd A_3LMultiple buses temporarily connected between
Ipass line B_1SAnd B_1L, B_2SAnd B_2L, B_3SAnd B_3LBut, corresponding
The insulated wires to be connected to each other.
Different.

Features of the bypass connection device 3 according to the present invention
Is the power supply S side and the load L of the watt hour meter 1 as shown in FIG.
Side for each bypass line B_1SAnd B_2S, B_3SAnd B_2S, B_1L
And B_2L, B_3LAnd B_2LAnd B_1SAnd B_1L, B_2SAnd B_2L, B_3S
And B_3LLine voltage V between_12S, V _32S, V_12L, V_32LPassing
And V_1SL, V_2SL, V_3SLDetects whether or not an error has occurred
Connection detection circuit 4 and a bypass on the power supply S side and the load L side.
Line B_1S~ B_3S, B_1L~ B_3LInsulated wire A through_1S~ A
_3S, A_1L~ A_3LIsolates whether a given current is flowing through
Wire A_1S~ A_3S, A_1L~ A_3LConnected to the load L side of
Flower CT₁~ CT _ThreeA current detection circuit 5 for detecting
Based on the detection output of the incorrect connection detection circuit 4 or the current detection circuit 5,
And the bypass line B_1S~ B_3S, B_1L~ B_3LAnd the power supply S side
Relay contact P connected to load L side₁~ P_ThreeOpen and close
A control circuit 6 such as a CPU.

The erroneous connection detection circuit 4 includes a power supply S side and a load L side.
Bypass line B_1SAnd B_2S, B_3SAnd B _2S, B_1LAnd B_2L, B
_3LAnd B_2LBetween different phases and B_1SAnd B_1L, B_2SAnd B_2L, B_3SWhen
B_3LLine voltage V between the in-phase_12S, V_32S, V_12L, V
_32LAnd V_1SL, V_2SL, V_{3S L}For detecting
It is. As a concrete means, as shown in FIG.
Outputs either ON or OFF state depending on the presence or absence of voltage
A photocoupler PC is used. That is, the photocoupler P
The input side of C (light emitting diode LED) is connected to each bypass line
B_1S~ B_3S, B_1L~ B_3LHigh resistance R in between_aThrough
And the output side [phototransistor Tr]
Converts the pulse-like output waveform of the photocoupler PC to post-processing.
Via a waveform shaping circuit 11 for level conversion for simplicity
Connected to the control circuit 6.

FIG. 2 shows a circuit configuration for detecting one line voltage. Actually, seven line voltages V _12S , V _32S , V _12L , V _32L and V _1SL , V _2SL ,
Since it is necessary to detect _V3SL , seven circuit configurations described above are provided. However, one waveform shaping circuit 11 can be shared between the bypass lines.

The current detection circuit 5 is connected across the resistor 12 which converts a current flowing through the current transformer CT ₁ to CT ₃ provided in insulated wires A _1L to A _3L 3 into a voltage , An amplifier 13 for extracting only the voltage [current component] generated at both ends thereof, and a comparator connected to the output of each amplifier 13 and comparing a voltage output from the amplifier 13 with a reference voltage output from a reference voltage generator 14. And a waveform shaper 16 connected to the output of each comparator 15 and shaping the waveform of the signal output from the comparator 15 and outputting it to the control circuit 6.

The operation of the bypass connection device 3 having the above configuration will be described below. When the worker goes through the bypass line B _1S
B _3S, B _1L ~B _3L insulated wire A by attachment of special tool 2
_1S to A _3S, the connection state on connected to the A _1L to A _3L checked by the bypass connecting device 3.

First, the bypass lines B _{1S to} B _3S and B _{1L to} B _3L
, The line voltage between the different phases of the bypass lines B _1S and B _2S , B _3S and B _2S , B _1L and B _2L , B _3L and B _2L on the power supply S side and load L side of the watt hour meter 1 V _12S , V _32S , V _12L , and V _32L are detected by the incorrect connection detection circuit 4. In the erroneous connection detection circuit 4, the line voltages V _12S , V _32S ,
V _12L and V _32L are reduced to predetermined levels and applied to the photocoupler PC. As a result, if the bypass wires B _{1S to} B _3S and B _{1L to} B _3L are correctly connected to the corresponding insulated wires A _{1S to} A _3S , A _{1L to} A _3L on the power supply S side and the load L side, Line voltages V _12S , V _32S , V _12L , and V _32L are generated between the lines B _1S and B _2S , B _3S and B _2S , B _1L and B _2L , B _3L and B _2L , and the line voltage V _12S , V _32S , V _12L , V _32L , an ON signal is output from the photocoupler PC.
Is input to the control circuit 6. This photo cap
Output from the control circuit 6 based on the ON signal of the PC.
Display, such as a light emitting diode to notify normal connection status
A lamp (not shown) lights up.

On the other hand, bypass lines B _{1S to} B _3S and B _{1L to} B _3L
There corresponding insulated wire A _1S ~A _3S, A _1L ~A or not connected to _3L, the bypass line _{B 1S ~B 3S, B 1L ~B} 3L special tool 2 is insulated wires A _1S to A at each end of the _3S , A _1L- A
_The bypass line B _1S is not in contact with the _3L core wire.
.About.B _3S, unless B _1L .about.B _3L connected correctly, the line voltage _{V 12S, V 32S, V 12L} , since V _32L is not generated, OFF signal from the photo-coupler PC is output, the
An OFF signal is input to the control circuit 6. This photo cap
Output from the control circuit 6 based on the OFF signal of the PC.
And an indicator lamp (not shown) that reports a connection error lights up.
And an alarm buzzer (not shown) sounds.

The ON signal or the OFF signal from the photocoupler PC is input to a control circuit 6 such as a CPU, and the control circuit 6 determines whether the connection states of the bypass lines B _{1S to} B _3S and B _{1L to} B _3L are good. is, the bypass line B _1S ~B _3S, B _1L ~
If B _3L has been properly connected [When the output of the photocoupler PC is ON signals], completing the bypass connection closes the relay contact P ₁ to P ₃ on the basis of the output from the control circuit 6.

In the erroneous connection detection circuit 4, prior to closing the relay contacts P _{1 to} P ₃ , the in-phase bypass line B _{1S is connected.}
And B _1L , B _2S and B _2L , B _3S and B _3L line voltages V _1SL , V
By detecting _2SL and V _3SL , the bypass lines B _1S to
In-phase insulated wires A _1S to which B _3S and B _{1L to} B _3L correspond
A _3S , A _{1L to} A _3L are detected whether they are securely connected,
If the line voltages V _1SL , V _2SL , V _3SL are not generated, the bypass lines B _{1S to} B _3S , B _{1L to} B _3L are connected to the in-phase insulated wires A _{1S to} A _3S , A _{1L to} A _3L. since the normal state, at which time, and so as to close the relay contact P ₁ to P _3.

By the completion of the bypass connection, even if the insulated wires A _{1S to} A _3S and A _{1L to} A _3L are removed from the watt-hour meter 1, the power supply S is connected to the bypass line B _{1S to} B _3S and B _{1L to} B _3L. Since power is supplied to the load L, a power failure state does not occur, and the watt hour meter 1 can be replaced in an uninterrupted state.

However, when connecting the bypass wires B _{1 to} B ₃ , the special tools 2 at both ends are connected to the insulated wires A _{1S to} A _3S ,
Even if it is securely connected to A _{1L to} A _3L , after that, in order to replace the watt hour meter 1, the insulated wires A _1S to
A _3S, but removing the A _1L to A _3L, this time, for example, the operator insulated wire A _1S to A _3S, bypass lines B ₁ .about.B without pulled from the power meter 1 with A _1L to A _3L insulated _{state 3} with the wires a _1S to a _3S, when pulled out a _1L to a _3L,
Stress is applied to the dedicated tool 2 and the bypass lines B ₁ to
Insulated wire A _1S to A _3S of B _3, there is a possibility that poor connection occurs between A _1L to A _3L.

Therefore, the watt hour meter 1 _{indicates that the} insulated wires A _1S to
At the time of removing A _3S , A _{1L to} A _3L , bypass lines B _{1 to} B
_It is necessary to check the connection state with the insulated wires A _{1S to} A _3S and A _{1L to} A _3L of No. ₃ . Therefore, the bypass lines B _1-
The connection state of B ₃ is monitored by the current detection circuit 5.

After the connection of the bypass lines B _{1 to} B ₃ is completed, the watt-hour meter 1 is connected to the insulated wire A _1S for replacement of the watt-hour meter 1.
To A _3S, Removing the A _1L to A _3L, the bypass line B ₁ .about.B
_A current will flow from the power supply S to the load L via ₃ . In the current detection circuit 5, this current is transmitted to the insulated wire A _1S
~A _3S, A _1L ~A current transformer CT ₁ is provided on the load L side of _3L ~
Detected by CT _3, the bypass line B ₁ .about.B ₃ based on the presence or absence of the current through the special tool 2 insulated wires A _1S to A
_3S, monitors whether a connection failure between A _1L to A _3L.

That is, the current transformer CT₁~ CT_ThreeCurrent
If it is flowing, based on the output signal from the current detection circuit 5,
Control circuit 6 for bypass line B₁~ B_ThreeConnection is good
, And conversely, the current transformer CT₁~ CT_ThreeCurrent
If not, the output signal from the current detection circuit 5
Control circuit 6 to bypass line B₁~ B_ThreeConnection status
It is determined to be defective. Specifically, the current detection circuit 5
Is the current transformer CT₁~ CT _ThreeTo the comparator 15
A set value based on the reference voltage generator 14 [for example, 10 m
A), and if it is larger than the set value,
Line A_1S~ A_3S, A _1L~ A_3LCurrent is flowing through
If it is smaller than the set value,_1S~ A_3S, A_1L
~ A_3LNo current is flowing through the
Power.

If the connection state of the bypass lines B _{1 to} B ₃ is bad, all the relay contacts P _{1 to} P ₃ are opened at the same time based on the output from the control circuit 6 to cut off the bypass connection. At this time, by the output of the control circuit 6 described above,
Although not shown, the indicator lamp that reports a connection error lights up.
And the alarm buzzer sounds.

As a result, when the watt hour meter 1 is replaced,
Insulated wire A from meter 1_1S~ A_3S, A _1L~ A_3LRemove
Line B due to operator error₁~ B_ThreeConnection
Even if a failure occurs, the connection failure is detected by the current detection circuit.
5 can be detected quickly by monitoring, all immediately
Relay contact P₁~ P_ThreeBy opening all
Bypass line B₁~ B_ThreeAnd insulated wire A_1S~ A_3S, A_1L~
A_3LCurrent on the load L side.
Breakage of the electrical equipment used can be prevented beforehand.

Here, the current detection circuit 5 starts monitoring when the connection of the bypass lines B _{1 to} B ₃ is completed and the relay contacts P _{1 to} P ₃ are closed.
Terminates after the completion exchange monitoring at the time of opening the relay contact P ₁ to P _3. Here, there is a state in which no electric device is used on the load L side. At this time, no current flows through all the insulated wires A _{1S to} A _3S and A _{1L to} A _3L . In this case, the insulated wire A
_1S to A _3S, starts the monitoring of the current flowing in the A _1L to A _3L, and erroneously determined the connection failure bypass line B ₁ .about.B ₃ to no current flows through the current transformer CT ₁ to CT ₃ , a situation which immediately result in open the relay contact P ₁ to P ₃ will occur.

In order to prevent this, current monitoring is started.
First, all insulated wires A_1S~ A_3S, A
_1L~ A_3LWhen no current is flowing through the
Then, the monitoring by the current detection circuit 5 ends. And without
A single insulated wire A_1S~ A _3S, A_1L~ A_3LEven current
Is flowing, the insulated wire A where the current is flowing_1S~
A_3S, A_1L~ A_3LMonitoring of electricity meter 1
Relay contact P after replacement₁~ P_ThreeUntil the opening of
If the current flowing through the
Line B₁~ B_ThreeAt the time when it is determined that
All relay contacts P in points₁~ P_ThreeOpen the bypass
Disconnect the connection.

The bypass connection device 3 as described above
Then, when using the electronic circuit including the control circuit 6 such as the CPU, when the worker completes the replacement work and forgets to turn off the power switch and moves to the next replacement work, the power switch remains ON. , The bypass line B _1S
B _3S, B _1L ~B _3L the following energy meter 1 of the insulated wire A _1S to A
_3S, when attempting to connect to the A _1L to A _3L, the bypass line B _1S
ＢB _3S , B _1L ＢB _3L are not completely connected and are in an unstable state, so that the power supply S is supplied to the control circuit 6 such as a CPU.
The control circuit 6 may malfunction. Therefore, every time the replacement work is completed, the worker must set the power switch to O.
After FF, it is necessary to move to the next replacement work,
The operator tends to forget to turn off the power switch, in which case the above-described problem may occur.

Therefore, the bypass connection device 3 of the present invention
The power supply is automatically turned on when the
Are provided. Specifically, as shown in FIG. 4, an AC / DC conversion circuit 8 connected to a power supply circuit 7 for driving the control circuit 6 at a predetermined voltage, and a circuit board 9 on which an electronic circuit including the control circuit 6 is mounted. between, the self-hold closed relay contact Q ₁ to Q ₃ in the excitation coil M ₁ ~M ₃ by turning on the power switch W, the bypass line B _1S .about.B _3S, the B _1L .about.B _3L insulated wire A _1S ~A _3S, A _1L ~
The power supply circuit 7 is provided with a forgetting to prevent disconnection circuit 10 for opening the relay contacts Q _{1 to} Q ₃ by disconnecting from the A _{3 L} to cut off the drive voltage from the power supply circuit 7.

First, when the operator starts the replacement work, the insulated wires A on the power source S side and the load L side of the watt hour meter 1 are used.
_1S ~A _3S, A _1L ~A _3L to the bypass line B _1S ~B _3S, B _1L ~
When turning on the power switch W After connecting the B _3L, off forgotten is energized coils M ₁ ~M ₃ circuit 10 closes the relay contact Q ₁ to Q _3, the drive voltage control circuit from the power supply circuit 7 6 is applied. Here, even if the power switch W returns to the open state, the control is performed because the bypass wires B _{1S to} B _3S and B _{1L to} B _3L are connected to the insulated wires A _{1S to} A _3S and A _{1L to} A _3L. since the circuit 6 to the coil M ₁ ~M ₃ predetermined voltage is applied to the relay contacts Q ₁ to Q ₃ for self-holding the closed state.

On the other hand, when the replacement work is completed,
Line A_1S~ A_3S, A_1L~ A_3LTo bypass line B_1S~ B_3S,
B_1L~ B_3LIs disconnected from the control circuit 6, the coil M₁
~ M _ThreeIs no longer applied to the coil M₁~
M_ThreeOf the relay contact Q₁~ Q_ThreeBut
It is automatically opened and the control circuit 6 is disconnected from the power circuit 7
You. As a result, when starting the next replacement work
Means that the drive voltage of the power supply circuit 7 is applied to the control circuit 6
There is no bypass line B_1S~ B_3S, B_1L~ B_3LInsulated electricity
Line A_1S~ A_3S, A_1L~ A_3LInstability when connecting to
Even if this occurs, the control circuit 5 does not malfunction.

It should be noted that the apparatus of the present invention is a single-phase 3
In addition to the wire type and the three-phase three-wire type, the present invention is also applicable to a single-phase two-wire type watt hour meter. That is, the apparatus of the present invention has a function of switching between a single-phase three-wire system, a three-phase three-wire system, and a single-phase two-wire system. It is set as follows.

However, when used for a single-phase two-wire watt-hour meter
Is incorrectly connected to the single-phase three-wire system or three-phase three-wire system described above.
The judgment criteria in the line detection circuit 4 are different. That is, the bypass line
B_1SAnd B_2S, B_3SAnd B_2S, B_1LAnd B_2L, B_3LAnd B_2LDifferent
Line voltage V between phases_12S, V _32S, V_12L, V_32Las well as
Bypass line B_1SAnd B_1L, B_2SAnd B_2L, B_3SAnd B_3LIn phase
Line voltage V between_1SL, V_2SL, V_3SLAbout single phase
In the case of a three-wire system or a three-phase three-wire system, the line voltage V between different phases
_12S, V_32S, V_12L, V_32LOccurs and is in phase
Line voltage V at_1SL, V_2SL, V_3SLMust occur
If the bypass line is connected properly,
In the case of the phase two-wire system, for example, insulated wire A_1S, A_2SAnd A_1L,
A_2LUsing insulated wire A_3S, A_3LDo not use
And the line voltage V between different phases_12S, V_12LOccurs
And the line voltage V between different phases_32S, V_{32 L}And in-phase
Line voltage V_1SL, V_2SL, V_3SLIf no
The IPASS line is normally connected.

[0043]

According to the bypass connection device of the present invention, the replacement of low-voltage gauges by short-circuiting can be performed erroneously in the replacement work of low-voltage gauges by the circuit configuration of the incorrect connection detection circuit, the current detection circuit and the control circuit. Power supply side and the load side can be reliably connected between the corresponding insulated wires, and when removing the low-voltage meter, check the connection status of the bypass line with the insulated wire and check the electrical connection at the load side. Failures such as destruction of equipment can be prevented beforehand, and safe and quick work with greatly reduced danger can be realized, and workability is greatly improved without requiring skilled workers.

Further, by adding a circuit for preventing the user from forgetting to turn off, a malfunction caused by forgetting to turn off the power switch can be eliminated, so that the reliability can be improved. In this way, it is possible to provide a bypass connection device that can easily prevent the erroneous connection of the bypass line to the insulated wire and the erroneous connection of the insulated wire to the low-voltage meter, and have a large practical value.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a bypass connection device according to the present invention.

FIG. 2 is a circuit block diagram showing a specific example of an incorrect connection detection circuit shown in FIG. 1;

FIG. 3 is a circuit block diagram showing a specific example of the current detection circuit shown in FIG.

FIG. 4 is a circuit block diagram illustrating a circuit for preventing forgetting to be cut added to the bypass connection device of FIG. 1;

FIG. 5 is a block diagram showing a state in which a bypass connection device is connected to an insulated wire of a wattmeter via a bypass line.

FIG. 6 is a block diagram showing a state in which a bypass line is connected to the insulated wire of the watt hour meter;

[Explanation of symbols]

1 low pressure meter [WHM] 4 improper wiring detection circuit 5 current detection circuit 6 control circuit 7 power circuit 10 off forgotten preventing circuit _{A 1S ~A 3S, A 1L ~A} 3L insulated wire B _1S ~B _3S, B _1L ~B _3L bypass line _{V 12S, V 32S, V 12L} , V 32L, V 1SL, V 2SL, V 3SL
Line voltage P ₁ to P ₃ relay contacts Q ₁ to Q ₃ relay contacts S power L load W power switch

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshitane Abe 3-12-15 Wakao-ji Temple, Amagasaki City, Hyogo Prefecture Inside Sonoda Keiki Kogyo Co., Ltd. No. 15 Sonoda Keiki Kogyo Co., Ltd. (72) Inventor Yukiyoshi Sato 3-12-15 Wakaoji Temple, Amagasaki-shi, Hyogo Prefecture Inside No. 15 Sonoda Keiki Kogyo Co., Ltd. No.12-15, Sonoda Keiki Kogyo Co., Ltd. (56) References JP-U 4-51670 (JP, U) JP-A 61-119274 (JP, U)

Claims (2)

(57) [Claims] A plurality of bypass lines connected between a power supply side and a load side of a low-voltage gauge and in a charged state and temporarily connected between a plurality of pairs of insulated wires are connected to a corresponding insulated wire.
To determine whether the connection is properly
I, whether or not the improper wiring detection circuit line voltage between each bypass line for the power supply side and load side detects whether occurring, the predetermined current to the insulated wire via the bypass line flows And a relay contact that connects the bypass line between the power supply side and the load side based on the detection output of the incorrect connection detection circuit or the current detection circuit. And a control circuit for opening and closing the bypass connection device. 2. A power supply switch is turned on to close a relay contact between a power supply circuit for driving the control circuit at a predetermined voltage and the control circuit, hold the relay contact, and disconnect a bypass line from the insulated wire. 2. The bypass connection device according to claim 1, further comprising a forgetting prevention circuit for opening a relay contact to cut off a driving voltage from the power supply circuit.