JP2005006417A - Lightning stroke protective device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent such a trouble that a thunder attack detecting circuit is switched into its initial state by a power failure thereby determining that there is no approach of thunder and switching a protected device to a normal state at the continuation of thunder approach. <P>SOLUTION: This lightning stroke protective device is equipped with the thunder attack detecting circuit which determines the existence of thunder approach by detecting a thunder signal, and a switching mechanism which switches the protected device into the normal state where it is connected to an electric path and a thunder-resistant state where it is cut off the electric path. The lightning stroke protective device is switched to the normal state at normality by the signal from the thunder attach detecting circuit and to the thunder-resistant state at the approach of thunder by means of the switching mechanism, getting control power from a low-voltage power line. The device determines the existence of thunder approach for a specified time after the recovery of control power in the case that the control power has failed, and it switches the protected device to the thunder-resistant state at the existence of the thunder approach, and to the normal state at the presence of the thunder approach. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a lightning damage protection device that detects a lightning surge generated by a lightning strike or the like and protects a device to be protected from a lightning surge that enters from a communication signal line or a low-voltage power line.
[0002]
[Prior art]
Commercial frequency low-voltage power lines are usually pulled down from high-voltage distribution lines to 100V by pole transformers and wired into buildings such as ordinary households. Electric equipment such as refrigerators, washing machines, air conditioners, and communication signal lines Also, electricity is supplied to electric devices such as TVs, telephones, facsimiles, personal computers, etc.
Lightning surges occur in low-voltage power lines or communication signal lines due to lightning strikes to high-voltage distribution lines, etc., and the lightning surges propagate through power lines or communication lines and enter buildings, and are connected to these lines. It is known to destroy existing electrical equipment.
In order to protect these electrical devices, for example, a lightning protection device that detects an abnormal voltage caused by a lightning surge and sends a control signal to display a lightning strike warning or the like has been proposed. (For example, see Patent Document 1.)
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-326108 (page 2-3, FIG. 1)
[0004]
In addition, in Japanese Patent Application No. 2002-258217, the present applicant judges whether or not lightning is approaching, and when lightning approaches, the protected device is connected from the low-voltage power line to the protected state from the normal state where the protected device is connected to the low-voltage power line. We have proposed a lightning protection system that protects protected equipment by switching to a lightning protection state.
[0005]
[Problems to be solved by the invention]
Since the above lightning protection system obtains the control power from the low-voltage power line, when the low-voltage power line fails due to lightning, it returns to the initial state due to the power failure.
When the control power supply recovers again, there is a problem that even during thunder approaching, it is switched to the normal state connected to the low-voltage power supply line due to initialization.
Or if there is no lightning approach after power failure after power failure after lightning protection, it will be in the initial state due to power failure, it will be judged that there is no lightning approach, and signal transmission will not be performed, and as a result, it will continue to maintain the lightning protection state There is a problem.
For this reason, it is conceivable to provide a backup power supply circuit using a battery or the like as a countermeasure in the event of a control power failure. However, in this case, there is a problem that maintenance of the backup power supply is required.
[0006]
[Means for Solving the Invention]
The present invention has been made to solve the above problems,
The invention described in claim 1 includes a lightning detection circuit that detects a lightning signal and determines whether there is a lightning approach, a normal state in which the protected device is connected to the electric circuit, and a lightning-proof state in which the protected device is disconnected from the electric circuit. In a lightning damage protection device comprising a switching mechanism for switching, obtaining a control power source from a low-voltage power line, and switching to a normal state by a signal from the lightning detection circuit, and switching to a lightning-resistant state by a switching mechanism when lightning approaches ,
When the control power supply fails, after the control power supply is restored, it is determined whether or not lightning is approaching for a predetermined time, and when lightning is approaching, it is in a lightning resistant state, and when there is no lightning approach, it is in a normal state. It is a lightning protection device.
[0007]
According to a second aspect of the present invention, there is provided a lightning protection transformer, an open / close mechanism that switches between a lightning protection state in which the lightning protection transformer is inserted into a circuit, and a normal state in which the lightning protection transformer is bypassed and separated from the circuit. And a lightning strike detection circuit for judging whether or not lightning is approaching, obtaining a control power supply from a low-voltage power line, and in a normal state by a signal from the lightning strike detection circuit, in a lightning protection state when lightning approaches In the lightning damage protection device switched by the opening and closing mechanism,
When the control power supply fails, after the control power supply is restored, it is determined whether or not lightning is approaching for a predetermined time, and when lightning is approaching, it is in a lightning resistant state, and when there is no lightning approach, it is in a normal state. It is a lightning protection device.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing a normal state of the first embodiment of the present invention.
This lightning damage protection device 1 is inserted between a power supply side power supply line 10 connected to a lead-in wire or the like drawn into the building from the outside and a load side power supply line 20 connected to the power supply of the protected device. Used in form.
A lightning protection element 90 composed of an arrester, a surge absorbing element or the like is connected between the power supply side power supply line 10 and the load side power supply line 20.
[0009]
The lightning damage protection device 1 includes a power supply circuit 4, a lightning strike detection circuit 5, operation control means 6, and a state changeover switch 7.
The power supply circuit 4 is connected to the power supply side power supply line 10, receives electricity from the power supply side power supply line 10, and supplies control power to the lightning strike detection circuit 5 and the operation control means 6.
[0010]
The lightning strike detection circuit 5 is a circuit that detects a lightning signal and determines whether there is a lightning approach,
Examples of the detection signal used to determine whether or not lightning is approaching can include lightning, thunder, radio waves, electrostatic field, and lightning surge propagating through the line. Are used to determine the presence of lightning approach by combining any one or more.
Misjudgment can be prevented by judging by combining a plurality.
[0011]
As a method of determining the presence or absence of thunder, for example, for thunder and thunder, when the light intensity and volume exceed a predetermined value, or the detection time difference between the thunder light and thunder with a light quantity and volume exceeding a predetermined value is less than a predetermined value. It can be determined that lightning is approaching.
Further, it can be exemplified that when a lightning surge exceeds a predetermined voltage value or current value, or when the occurrence frequency of a lightning surge exceeding the predetermined value exceeds a predetermined value, it is determined that the lightning is approaching.
[0012]
When the lightning strike detection circuit 5 determines that a lightning is approaching, a signal for switching to a lightning resistance state is sent to the operation control means 6 so that there is no lightning signal exceeding a predetermined value or no lightning signal exceeding a predetermined value, and When a predetermined time has elapsed, a switching signal to the normal state is sent to the operation control means 6 assuming that the lightning approaching state has been released.
As the switching signal, for example, during the lightning approaching state, the operation control unit 6 continuously sends the switching signal to the lightning protection state, and when there is no switching signal to the lightning protection state, the operation control unit 6 indicates that it is in the normal state. It is also possible to make a judgment at.
[0013]
The operation control means 6 controls the switching operation of the contact of the state changeover switch 7 from the normal state shown in FIG. 1 to the lightning resistant state shown in FIG. 2 according to the lightning approaching state signal from the lightning strike detection circuit 5. The drive unit such as a motor or magnet of the state changeover switch 7 to be described later is operated to connect the protected device and the power supply side power line 10 in the normal state, and the protected device is connected from the power supply side power line 10 in the lightning protection state. The state switch 7 is automatically operated so as to be shut off.
When the lightning approaching state is canceled, the operation is switched from the lightning resistant state shown in FIG. 2 to the normal state shown in FIG.
Further, the operation control means 6 maintains the previous state until a signal from the lightning strike detection circuit 5 is sent.
[0014]
The state changeover switch 7 is connected to the load-side power line 20 and the lightning protection for disconnecting the protected apparatus from the power-side power line 10 and the normal state in which the protected apparatus (not shown) connected to the power-side power line 10 is connected. An open / close mechanism including a mechanical contact switch for switching between states, for example, an automatic switch operated by a driving unit such as a motor or a magnet, or an electromagnetic contactor such as a breaker or a keep relay. By using these, the current normal state or lightning resistance state can be mechanically maintained even in a non-voltage state.
[0015]
Further, the state changeover switch 7 has a withstand voltage performance of, for example, about 30 kV to withstand the overvoltage of the lightning surge in order not to propagate the lightning surge to the load-side power line 20 when the power is disconnected.
[0016]
FIGS. 3 and 4 are explanatory views showing a second embodiment of the present invention using a lightning transformer 30, and the same components as those in FIGS.
FIG. 3 is an explanatory diagram showing the normal state. In the normal state, the lightning resistant transformer 30 is disconnected from the electric circuit, and connected to the load-side power line 20 by the bypass line 8 to the protected device (not shown) on the power source side. Electricity is supplied from the power line 10.
[0017]
FIG. 4 is an explanatory diagram of the lightning protection state when the lightning protection state is switched in FIG. 3. When the lightning strike detection circuit 5 determines that the lightning is approaching, the operation control means 6 sets the state changeover switch 7 to the lightning protection state. The lightning transformer 30 is inserted between the power supply side power line 10 and the load side power supply line 20 so as to supply electricity to a protected device (not shown) connected to the load side power supply line 20. It has become.
[0018]
By using the lightning resistant transformer 30, it is possible to prevent lightning surge entering from the power source side from propagating to the load side by the lightning resistant transformer 30, and to protect the protected equipment without causing a power failure of the protected equipment even in the lightning resistant state. Can be supplied with electricity.
[0019]
In particular, by using an automatic switch or the like that is operated by a magnet and setting the switching time of the state switch 7 to 10 milliseconds or less, the protected device can be switched in a substantially uninterrupted state. , It is possible to eliminate the power failure of the protected device at the time of switching.
In addition, since the lightning resistant transformer 30 can be separated from the electric circuit during normal times, there is an effect of eliminating power consumption due to no-load loss such as iron loss of the lightning resistant transformer 30.
[0020]
Further, in the case of a device such as a personal computer connected to both a power line and a communication line, a state changeover switch 7 is provided on both the power lines 10 and 20 and the communication lines 11 and 21 as shown in FIG. Thus, the protected device can be protected.
The same components as those shown in FIG.
In FIG. 5, the lightning transformer 30 can be inserted between the power supply line 10 and the load power supply line 20 as shown in FIG. 3, or only on the communication lines 11 and 21. It is also possible to provide a state switch 7 to switch between the normal state and the lightning protection state.
[0021]
Next, the operation when the power supply side power supply line 10 is interrupted by a lightning strike will be described. The power supply to the power supply circuit 4 of the lightning protection device 1 is lost due to a power failure, and the operation of the lightning detection circuit 5 is stopped.
At this time, since the state changeover switch 7 is mechanically held, the normal state immediately before the power failure or the lightning protection state can be maintained even during the power failure.
[0022]
When an electromagnetic contactor such as a relay that returns with no voltage is used for the state changeover switch 7, the state immediately before the power failure is indicated in the operation control means 6 by an electrical means such as a memory or a mechanical means such as a keep relay. By storing it, the state immediately before the power failure can be easily restored immediately after the power is restored.
Further, by storing the state immediately before the power failure in the operation control means 6, it is possible to reliably operate the state change switch 7 in the middle of the operation to the normal position when the power is restored with respect to the power failure during the operation of the state switch 7. .
[0023]
After power recovery, the lightning detection circuit 5 detects the presence or absence of lightning for a predetermined time. As a result, a switching signal is set so that when lightning is approaching, the lightning is protected, and when no lightning is approaching, the lightning is normal. The data is sent to the operation control means 6.
As the predetermined time, an arbitrary time between several seconds and several tens of minutes can be set.
[0024]
By making the lightning strike detection circuit 5 detect the presence or absence of lightning approach for a predetermined time after the power is restored, the lightning strike detection circuit 5 is in an initial state due to a power failure, and to the operation control means 6 by determining that there is no lightning approach It is possible to eliminate the transmission of a switching signal to bring the normal state to the normal state.
Alternatively, if there is no lightning approach after a power failure and power recovery after a lightning-resistant state, the lightning strike detection circuit 5 is in an initial state due to the power failure, and it is determined that there is no lightning approach, and no signal is sent to the operation control means 6. It can be prevented that the lightning resistance state is continuously maintained.
Furthermore, it is possible to correctly recognize the presence or absence of lightning approach immediately after the power supply is restored, thereby preventing erroneous determination.
[0025]
In this way, even if there is no backup power supply for ensuring operation during a power failure, the thunder detection circuit 5 is in an initial state due to a power outage when a lightning approach is continued, and the thunder detection circuit 5 determines that there is no thunder approach and enters a normal state. Switching can be easily prevented, and lightning damage to the protected device due to a power failure can be prevented.
Alternatively, the lightning resistance state can be maintained and the supply of electricity to the protected device can be stopped.
[0026]
When the lightning transformer 30 is used, a lightning protection state may be set once when the power is restored, thereby preventing a lightning damage from occurring immediately after the power is restored.
[0027]
【The invention's effect】
According to the invention of claim 1 of the present invention,
If the control power supply of the lightning protection device is lost due to a power failure due to a lightning strike, etc., even if there is no backup power supply for ensuring the operation during a power failure, the lightning strike detection circuit will be in the initial state due to the power failure when the lightning approaches, and the lightning strike detection circuit Therefore, it can be easily prevented that it is determined that there is no lightning approach and switched to a normal state, and lightning damage to the protected device due to a power failure can be prevented.
Or, if there is no lightning approach after power failure after power failure after lightning protection, the lightning strike detection circuit will be in the initial state due to power failure, it will be judged that there is no lightning approach, and no signal will be sent to the operation control means, lightning protection state Can be prevented from continuing.
Furthermore, since the presence of lightning approaching immediately after power recovery can be recognized correctly by making a judgment on whether lightning is approaching for a predetermined time after power recovery, it is possible to prevent erroneous determination due to initialization of the lightning protection device. Protection equipment can be protected from lightning damage.
[0028]
Further, according to the invention of claim 2, by using a lightning resistant transformer, in addition to the above, it is possible to prevent the lightning surge entering from the power source side from propagating to the load side by the lightning resistant transformer, and to protect the protected device even in the lightning resistant state. It is possible to protect the protected device from lightning damage in a state where electricity is supplied to the protected device without causing a power failure, and it is possible to eliminate power consumption due to iron loss of a lightning-proof transformer in normal times.
Since only a short time during lightning approach is required, a relatively small lightning-resistant transformer can be used.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a normal state of a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a lightning protection state of the first embodiment of the present invention.
FIG. 3 is an explanatory view showing a normal state of the second embodiment of the present invention.
FIG. 4 is an explanatory view showing a lightning protection state of the second embodiment of the present invention.
FIG. 5 is an explanatory view showing a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lightning protection device 2 Power supply 3 Load 4 Power supply circuit 5 Strike detection circuit 6 Operation control means 7 State changeover switch 8 Bypass line 10 Power supply side power supply line 20 Load side power supply line 11, 21 Communication line 30 Lightning protection transformer 90 Arrester

Claims (2)

A lightning detection circuit that detects lightning signals and determines the presence or absence of lightning,
An open / close mechanism that switches between a normal state in which the protected device is connected to the electric circuit and a lightning protection state in which the protected device is disconnected from the electric circuit,
In a lightning damage protection device that obtains a control power supply from a low-voltage power supply line and switches to a normal state during normal times by a signal from the lightning detection circuit, and switches to a lightning resistant state when lightning approaches by the opening and closing mechanism,
When the control power supply fails, after the control power supply is restored, it is determined whether or not lightning is approaching for a predetermined time, and when lightning is approaching, it is in a lightning resistant state, and when there is no lightning approach, it is in a normal state. Lightning protection device An opening / closing mechanism that switches between a lightning-resistant transformer and a lightning-proof state in which the lightning-proof transformer is inserted into the electric circuit, and a normal state in which the lightning-resistant transformer is bypassed and disconnected from the electric circuit.
Equipped with a lightning detection circuit that detects lightning signals and determines the presence or absence of lightning,
In a lightning damage protection device that obtains a control power supply from a low-voltage power supply line and switches to a normal state during normal times by a signal from the lightning detection circuit, and switches to a lightning resistant state when lightning approaches by the opening and closing mechanism,
When the control power supply fails, after the control power supply is restored, it is determined whether or not lightning is approaching for a predetermined time, and when lightning is approaching, it is in a lightning resistant state, and when there is no lightning approach, it is in a normal state. Lightning protection device

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