JP2004048940A - Thunder resistant system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thunder resistant system for eliminating a power loss caused by a thunder resistant transformer at a normal time. <P>SOLUTION: The thunder resistant system 1 comprises a thunder resistant transformer 11, bypass line 12, state switching switch 13, precursor phenomenon detecting means 14, lightening strike detecting means 15, operation control means 16, electromagnetic wave measuring means 191, and electrostatic field measuring means 192. The precursor phenomenon detecting means 14 and the lightening strike detecting means 15 detect a ground discharge. The state switching switch 13 makes the thunder resistant transformer into such state as plugged into a power supply line only in such period as to protect against the thunder surge from the ground discharge, while the thunder resistive transformer is disconnected from the power supply line when the precursor phenomenon disappears, so the power loss caused by the thunder resistive transformer at a normal time is eliminated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lightning protection system including a lightning protection transformer for preventing transmission of a lightning surge generated by a lightning strike from a power supply line to a load. More specifically, the present invention relates to a lightning protection system that can eliminate power loss caused by a lightning protection transformer in normal times.
[0002]
[Prior art]
2. Description of the Related Art In order to protect an electric device as a load from a lightning surge intruding from a power supply line, a lightning-resistant system in which a lightning-resistant transformer that absorbs a lightning surge is inserted into a power supply line has conventionally been used.
[0003]
[Problems to be solved by the invention]
However, the lightning-resistant transformer has a large power loss due to iron loss, for example, about 3 to 10% of the transformer capacity. For this reason, a lightning-resistant means with little power loss is desired.
An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a lightning protection system capable of eliminating power loss caused by a lightning protection transformer in normal times.
[0004]
[Means for Solving the Problems]
The lightning protection system according to the first aspect of the present invention is a lightning protection system for a power supply line including a lightning protection transformer, the lightning protection transformer, a bypass line, a normal state in which the bypass line is inserted into the power supply line, or the lightning protection transformer. A state changeover switch that switches between lightning proof states inserted into the power supply line, a precursory phenomenon detecting means that detects a approaching approach of a thundercloud or a precursory phenomenon of lightning strike from at least one measurement result of an electromagnetic wave, an electrostatic field, and a lightning surge; When the precursor phenomenon is detected by the precursor phenomenon detecting means, the state changeover switch is switched to the lightning proof state, and after the precursor phenomenon is not detected, the operation control means for switching the state changeover switch to the normal state, It is characterized by having.
[0005]
Further, the operation control means can switch to the normal state after a lapse of a predetermined precursor period after the precursor phenomenon is not detected.
Further, the present lightning protection system further comprises lightning strike detection means for detecting the lightning strike from at least one measurement result of lightning, thunder, lightning surge, electromagnetic wave and electrostatic field, and the operation control means, wherein the precursor phenomenon is not detected. The state change switch can be switched to the normal state after the occurrence of the lightning or after the lightning is detected by the lightning detection means. Further, the operation control means, after a predetermined precursor period calculated from the time when the precursor phenomenon is not detected, and after a predetermined lightning period calculated from the time when the lightning phenomenon is detected, The state can be switched to the normal state.
[0006]
When switching between the normal state and the lightning proof state, the state change switch is configured such that only one of the bypass line and the lightning proof transformer is inserted into the power supply line after passing through a state in which both are inserted into the power supply line. Can be inserted.
[0007]
The apparatus further comprises a manual operation switch and manual operation instruction means, wherein the manual operation instruction means instructs the operation control means to perform a manual operation or a manual operation release in accordance with the operation of the manual operation switch, and the operation control means When the operation is instructed, the state switch can be switched to the lightning proof state, and when the manual operation cancellation is instructed, the state switch can be switched to the normal state.
The operation control means is configured to switch the state changeover switch to the lightning proof state, and / or to receive the manual operation release instruction until a predetermined lightning proof maintenance period elapses after the detection of the precursor phenomenon. The operation of switching to the normal state can not be performed.
Further, the present lightning protection system can be used by being arranged at the entrance of the power supply line.
[0008]
【The invention's effect】
According to this lightning protection system, the lightning protection transformer is inserted into the power supply line only during the period when it is necessary to protect against lightning surges caused by lightning strikes. Power loss due to the transformer can be eliminated.
Furthermore, since the lightning-resistant transformer can be separated from the power supply line after a lightning strike, power loss due to the lightning-resistant transformer in normal times can be eliminated.
[0009]
In addition, set a predetermined precursor period, and return to a normal state after the precursor period from the time when the precursor phenomenon is no longer detected, so protect with a lightning protection transformer only during the period when lightning may occur, and reduce power loss. Can be. Further, by setting a predetermined lightning strike period and maintaining a lightning proof state for the lightning strike period even if there is a lightning strike, it is possible to provide protection with a lightning proof transformer even if multiple lightning strikes (multiple lightning strikes) occur with one lightning strike. .
In addition, since the state change switch has a structure in which the lightning protection transformer and the bypass line are simultaneously connected at the time of the switching and only one of them is connected, the power line is not disconnected even temporarily, and the power failure occurs. No condition occurs.
[0010]
Further, by providing the manual operation switch and the manual operation instructing means, the lightning protection state can be manually set, and the protection from the lightning surge can be performed more reliably. Furthermore, the manual release of the lightning proof state cannot be performed during the lightning proof maintenance period, so that damage due to erroneous operation can be prevented.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The above-mentioned "lightning-resistant transformer" may be any transformer as long as it can absorb lightning surge, and its type is not particularly limited. The “bypass line” is a wiring used in place of the lightning proof transformer in a normal state where the lightning proof transformer is not inserted into the power supply line.
[0012]
The “state switch” is a switch that can switch whether to bypass the lightning proof transformer by a bypass line. The type of the state change switch may be a mechanical contact, a semiconductor type, or the like as long as it can be controlled by the operation control means.
When the switching is performed, a shorting structure in which only one of the bypass line and the lightning protection transformer is connected to the power supply line and then only one of the bypass line and the lightning protection transformer is connected to the power supply line as shown in the fifth invention is preferable. This is because in the case of non-shorting, the power is cut off during switching, which is not preferable for the load, and the switching may not be performed correctly due to an arc at the time of cutting.
[0013]
The conditions of the electromagnetic wave, the electrostatic field, and the lightning surge used for the detection by the "precursor phenomenon detecting means" may be arbitrarily selected as long as the precursory phenomenon occurring before the lightning strike can be determined.
For example, the frequency band of the electromagnetic wave used for detecting the precursor phenomenon is not particularly limited, but is usually 1 MHz or more (hereinafter referred to as high frequency). This is because, as shown in FIG. 3, a change that appears to be a precursor phenomenon is observed in the high-frequency electromagnetic wave, and this can be detected.
Further, as shown in FIG. 3, it can be exemplified that the electrostatic field is determined to be a precursor phenomenon when it exceeds a predetermined strength. Further, it can be exemplified that a lightning surge is determined to be a precursor phenomenon when a predetermined voltage value or a current value is exceeded or when a change in the voltage or current exceeds a predetermined range.
[0014]
The conditions of lightning, thunder, lightning surge, electromagnetic wave, and electrostatic field used for the detection by the "lightning detection means" may be any conditions as long as they can be determined as lightning.
For example, it can be mentioned that the lightning and the thunder are determined to have exceeded a predetermined value. In addition, lightning surge can be exemplified as judging a precursor phenomenon when the voltage or current value exceeds a predetermined voltage value or when a change in the voltage or current exceeds a predetermined range. Further, the frequency band of the electromagnetic wave used for detecting the lightning strike is not particularly limited, but is usually 10 Hz to 100 kHz (hereinafter referred to as low frequency). This is because, as shown in FIG. 3, a pulse due to a lightning strike is seen in a low-frequency electromagnetic wave, and this can be detected. In addition, as shown in FIG. 3, it can be exemplified that it is determined that a lightning strike has occurred when the static electric field exceeds a predetermined strength and drops sharply.
[0015]
The “precursor period” is a predetermined period that starts when the precursor phenomenon is not detected. This period can be arbitrarily selected as long as it is equal to or longer than the interval between lightning strikes, and may be any length exceeding the normal interval between lightning strikes of about 40 ms. Examples of this include, but are not particularly limited to, 50 ms, 100 ms, 1 second, 10 seconds, 1 minute, 30 minutes, and 1 hour.
The “lightning strike period” is a predetermined period starting from the time when a lightning strike occurs. This period can be arbitrarily selected as long as it is equal to or longer than the interval between lightning strikes, and may be any length exceeding the normal interval between lightning strikes of about 40 ms. Examples of this include, but are not particularly limited to, 50 ms, 100 ms, 1 second, 10 seconds, 1 minute, 30 minutes, and 1 hour.
[0016]
The “lightning proof maintenance period” is a period for maintaining the lightning proof state. During this lightning protection period, even if the manual operation switch is instructed to cancel the manual operation, it is possible to prevent the lightning protection state from switching to the normal state. Further, the lightning resistance maintenance period is a predetermined period starting from when the lightning protection state is switched, when one of the above-described precursory phenomena is detected, and when the above lightning strike is detected, or when two or more are satisfied. This period that can be performed can be arbitrarily selected as long as it is equal to or longer than the interval between lightning strikes, and may be any length that exceeds the normal electric shock interval of about 40 msec. Examples of this include, but are not particularly limited to, 50 ms, 100 ms, 1 second, 10 seconds, 1 minute, 30 minutes, and 1 hour.
[0017]
The above-mentioned “inlet” means an arbitrary place between the power meter and the distribution board. This is because all the loads can be protected from lightning by connecting and using the lightning protection system to the power supply line during this time. Further, the lightning protection system can be installed and used on an arbitrary place such as a floor near a distribution board shown in FIG. 7, a closed box, an attic, and a warehouse.
[0018]
【Example】
1. Configuration of Lightning Protection System The lightning protection system 1 of the first embodiment is used by being inserted into a single-phase three-wire power line 21 including a neutral wire. As shown in FIG. 1, a lightning proof transformer 11, a bypass line 12, a state changeover switch 13, a precursory phenomenon detecting means 14, a lightning strike detecting means 15, an operation control means 16, an electromagnetic wave measuring means 191, And an electrostatic field measuring unit 192. Further, an arrester 193 is provided between the power supply lines 21 and the ground line.
[0019]
The lightning protection system 1 is used by being inserted into a power supply line 21 between a power supply 2 and a load 3. Specifically, it is used by arranging it at the entrance of a power supply line (a section from the wattmeter 22 to the distribution board 23 shown in FIG. 6) such as a house or an office. Also, as shown in FIG. 6, the lightning protection system 1 is inserted and used, for example, in the wiring in the distribution board 23. Further, as shown in FIG. 7, the lightning proof system 1 is installed and used on the floor of the entrance where the distribution board 23 is provided.
[0020]
The lightning-resistant transformer 11 is a transformer that insulates between the primary and secondary sides of the transformer and can absorb a lightning surge or the like.
The bypass line 12 is a wiring connected to the power supply line 21 in a normal state where the lightning protection transformer is not inserted into the power supply line 21.
The state changeover switch 13 is a mechanical contact switch for switching the lightning protection transformer 11 or the bypass line 12 to the power supply line 21 for connection. The state switch 13 is provided with two sets of a state switch 131 on the power supply side and a state switch 132 on the load side.
[0021]
In a normal state, the bypass line 12 is connected to the power supply line 21. Further, in the lightning proof state, the lightning proof transformer 11 is connected to the power supply line 21. The state changeover switch 13 has a shorting structure in which the state in which the power supply line is disconnected does not occur, that is, the state in which the bypass line 12 and the lightning protection transformer 11 are connected to only one of the power supply lines 21 after the state is connected. Has become.
[0022]
The electromagnetic wave measuring unit 191 and the electrostatic field measuring unit 192 measure the electromagnetic wave and the electrostatic field, respectively, and notify the obtained results to the precursory phenomenon detecting unit 14 and the lightning strike detecting unit 15.
The precursor phenomenon detecting means 14, the lightning strike detecting means 15, and the operation control means 16 are constituted by a logic circuit, a microcomputer or the like.
[0023]
The precursor phenomenon detecting means 14 is a means for detecting a precursor phenomenon of a lightning strike from the measurement results of the electromagnetic wave and the electrostatic field. Further, although a specific method of detecting the precursor phenomenon can be arbitrarily selected, as shown in FIG. 3, in this embodiment, the intensity of the electrostatic field exceeds a predetermined value, and the magnitude of the high-frequency component of the electromagnetic wave is a predetermined value. It is judged that the precursor phenomenon could be detected when it exceeded. Further, the detection result is transmitted to the operation control means 16.
[0024]
The lightning strike detecting means 15 is a means for detecting a lightning strike from the measurement results of the electromagnetic wave and the electrostatic field. Although a specific method of detecting electric shock can be arbitrarily selected, as shown in FIG. 3, in this embodiment, the intensity of the electrostatic field exceeding a predetermined value sharply decreases, and the magnitude of the low frequency component of the electromagnetic wave is reduced. It is determined that the electric shock has been detected when the value exceeds a predetermined value. Further, the detection result is transmitted to the operation control means 16.
[0025]
The operation control unit 16 is a unit that controls the state changeover switch 132 based on the notification from the precursor phenomenon detecting unit 14 and the lightning strike detecting unit 15. When the precursor phenomenon detecting means 14 notifies that the precursor phenomenon has been detected, the state switch 132 is switched to the lightning-resistant state. In addition, when the notification of the precursor phenomenon from the precursor phenomenon detecting means 14 disappears, or when the lightning detecting means 15 notifies that the lightning has been detected, the state changeover switch 132 is switched to the normal state.
[0026]
2. Operation and Effect of Lightning Protection System The operation and effect of the lightning protection system according to the first embodiment will be described in detail below.
(1) Normal state In a normal state in which no lightning strike occurs, as shown in FIG. 1, the power supply line 21 is connected to the load 3 via the bypass line 12 by the state change switch 132. Further, the lightning proof transformer 11 is disconnected from the power supply line 21 and is in a state of no power supply. Therefore, no power loss occurs due to the lightning-resistant transformer 11.
Further, the precursor phenomenon detecting means 14 and the lightning strike detecting means 15 detect whether a precursor phenomenon and a lightning strike have occurred, respectively.
[0027]
(2) Precursor Phenomenon Detection When the precursor phenomenon detecting means 14 exceeds a predetermined magnitude in the high frequency component of the electromagnetic wave and the electrostatic field, it is determined that a precursor phenomenon has occurred, and the operation controlling means 6 is notified of the precursor phenomenon. Perform Further, as shown in FIG. 2, the operation control means 6 controls the state switch 132 to switch to the lightning proof state.
[0028]
As a result, the bypass line 12 is disconnected from the power supply line 21, the lightning protection transformer 11 is connected to the power supply line 21, and the lightning protection transformer 11 is inserted between the power supply 2 and the load 3. Even if a lightning strike occurs, the lightning surge generated by the lightning strike can be absorbed by the lightning-resistant transformer 11. Further, even if the switching occurs, the load 3 is not disconnected from the power supply line 2 because the state changeover switch 132 has the shorting structure, and the power failure state does not occur.
[0029]
(3) Lightning Detection The lightning detection means 15 determines that a lightning strike has occurred when a change that appears to be a lightning strike occurs in the low-frequency component of the electromagnetic wave and the electrostatic field, and notifies the operation control means 6 of the lightning strike. Further, the operation control means 6 having received the notification of the lightning strike controls the state switch 132 to switch to the normal state after the elapse of the lightning strike period, as shown in FIG.
[0030]
Thus, after a lightning strike, the lightning protection transformer 11 inserted into the power supply line 21 is cut off, and power loss can be suppressed again. In addition, since the disconnection is performed after the elapse of the electric shock period, even if a continuous lightning strike occurs, it does not return to a normal state on the way, and it is possible to prevent lightning surge from being absorbed. Further, even if the switching occurs, the load 3 is not disconnected from the power supply line 2 because the state changeover switch 132 has the shorting structure, and the power failure state does not occur.
If the lightning is detected again before the lightning period has elapsed, the lightning period is set again from the last lightning.
[0031]
(4) When the Precursor Phenomenon Is Not Detected Without Generating Lightning There is a case where the precursory phenomenon detecting means 14 cannot detect the precursory phenomenon without the lightning strike detecting means 15 detecting the electric shock. In such a case, the operation control means 6 controls the state switch 132 to switch to the normal state after the lapse of the precursor period from the time when the precursor phenomenon is not detected, as shown in FIG.
As a result, the lightning protection transformer 11 inserted into the power supply line 21 is disconnected, and power loss can be suppressed again. In addition, since the disconnection is performed after the elapse of the precursor period, even if a lightning strike occurs, it does not return to a normal state on the way, and it is possible to prevent the lightning surge from being absorbed.
If a lightning stroke is detected before the elapse of the precursor period, the state returns to the normal state after the elapse of the lightning period.
[0032]
3. FIG. 4 shows a lightning-resistant system having a manually operated switch as a second embodiment of the present invention.
The second embodiment includes a manual operation switch 17 and a manual operation instruction means 18 in addition to the lightning protection system of the first embodiment shown in FIG.
The manual operation switch 17 is a switch for instructing the lightning protection system to perform a manual operation or a manual operation cancellation. Further, the manual operation instructing unit 18 notifies the operation control unit 6 of the manual operation or the manual operation cancellation instructed by the manual operation switch 17.
Further, the operation control means 6 controls the state changeover switch 132 in response to notification of manual operation or the like from the manual operation instruction means 18 in addition to the operation of the operation control means 6 of the first embodiment.
[0033]
4. Operation and effect of the lightning protection system including the manual operation switch Hereinafter, the operation and effect of the lightning protection system of the second embodiment will be described in detail. Note that the operation in the normal state is the same as the operation of the lightning proof system of the first embodiment, and a description thereof will be omitted.
[0034]
(1) At the time of instructing the manual operation When the manual operation switch 17 is operated to instruct the lightning protection system to perform the manual operation, the manual operation instruction means 18 notifies the operation control means 6 that the manual operation has been instructed. The operation control means 6, which has been notified of the manual operation, controls the state changeover switch to switch to the lightning proof state in the same manner as at the time of detecting the precursory phenomenon.
Thus, even if a lightning strike occurs, the lightning surge generated by the lightning strike can be absorbed by the lightning-resistant transformer 11. In other words, by switching to the lightning-resistant state earlier than the precursory phenomenon of lightning, it is possible to more reliably protect from lightning.
[0035]
(2) Lightning Detection At the time of lightning detection, the lightning detection means 15 determines that a lightning strike has occurred when a change that appears to be a lightning strike appears in the low-frequency component of the electromagnetic wave and the electrostatic field, and controls the operation in the same manner as the operation of the lightning protection system of the first embodiment. The means 6 is notified of the lightning strike.
Further, the operation control means 6 having received the notification of the lightning strike controls the state changeover switch 132 to switch to the normal state after the lightning strike period and the lightning resistance maintenance period have elapsed.
[0036]
(3) At the time of manual operation cancellation When the manual operation switch 17 is operated to instruct the lightning protection system to cancel the manual operation, the manual operation instruction means 18 notifies the operation control means 6 that the manual operation cancellation has been instructed. Further, the operation control means 6 having received the notification of the manual operation release controls the state switch to switch to the normal state after the lightning strike period and the lightning resistance maintenance period have elapsed.
In this way, by maintaining the lightning proof state until the lightning strike period and the lightning proof maintenance period elapse, it is possible to prevent accidental normalization when lightning strikes occur and fall into a state where the load 3 cannot be protected. can do.
[0037]
5. Lightning-Resistant System of Other Embodiments The present invention is not limited to the above-described embodiment, but may be variously modified within the scope of the present invention depending on the purpose and application. That is, as shown in FIG. 5, the state changeover switch 132 is omitted, and a lightning protection system in which the load-side lightning protection transformer 11 and the bypass line 12 are always connected can be configured.
In such a lightning proof system, power loss due to no-load excitation loss of the lightning proof transformer always occurs as compared with the lightning proof systems of the first and second embodiments, but the power loss due to the conventional lightning proof transformer can be reduced. Further, since the number of the state changeover switches 13 is reduced, the failure rate of the lightning proof system is reduced, and the cost required for manufacturing can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration of a lightning protection system in a normal state according to a first embodiment.
FIG. 2 is a schematic diagram for explaining a configuration of a lightning proof system in a lightning proof state according to the first embodiment.
FIG. 3 is a graph for explaining changes in an electromagnetic wave and an electrostatic field caused by a lightning strike.
FIG. 4 is a schematic diagram illustrating a configuration of a lightning proof system according to a second embodiment.
FIG. 5 is a schematic diagram for explaining a configuration of a lightning proof system in which a state switch on a load side is omitted.
FIG. 6 is a schematic diagram for explaining a state in which the lightning proof system is connected to a distribution board, which is an entrance of a power line.
FIG. 7 is a schematic diagram for explaining a state in which a lightning protection system is connected to a service entrance and disposed.
[Explanation of symbols]
1; lightning-resistant system; 11; lightning-resistant transformer; 12; bypass line; 13, 131, 132; state changeover switch, 14; precursor phenomenon detection means, 15; lightning strike detection means, 16; operation control means, 17; 18; manual operation instructing means, 191; electromagnetic wave measuring means, 192; electrostatic field measuring means, 2; power supply, 21; power supply line, 3;

Claims (8)

A lightning protection system for a power line having a lightning transformer, wherein the lightning transformer, a bypass line, and a normal state in which the bypass line is inserted into the power line, or the lightning transformer is inserted into the power line. A state changeover switch that switches between lightning proof states,
Precursor phenomenon detecting means for detecting approach of a thundercloud or a precursory phenomenon of lightning strike from at least one measurement result of electromagnetic waves, electrostatic field and lightning surge,
When the precursor phenomenon is detected by the precursor phenomenon detecting means, the state changeover switch is switched to the lightning proof state, and after the precursor phenomenon is not detected, the operation control means switches the state changeover switch to the normal state. A lightning proof system comprising: The lightning protection system according to claim 1, wherein the operation control unit switches to the normal state after a lapse of a predetermined precursor period after the precursor phenomenon is not detected. Lightning light, thunder, lightning surge, electromagnetic wave and lightning strike detection means for detecting the lightning strike from at least one measurement result of an electrostatic field, further comprising:
2. The lightning protection system according to claim 1, wherein the operation control means switches the state changeover switch to the normal state after the precursor phenomenon is not detected or after the lightning detection means detects the lightning stroke. The operation control means, after a predetermined precursor period calculated from the time when the precursor phenomenon is not detected, and a predetermined lightning period calculated from the time when the lightning phenomenon is detected, the normal state, The lightning protection system according to claim 1 or 3, wherein the system is switched to a state. When switching between the normal state and the lightning-resistant state, the state change switch is configured such that only one of the bypass line and the lightning-resistant transformer is inserted into the power supply line, and then only one of the bypass lines and the lightning-resistant transformer is connected to the power supply line. The lightning protection system according to any one of claims 1 to 4, which is inserted. A manual operation switch and a manual operation instructing unit, wherein the manual operation instructing unit instructs the operation control unit to perform a manual operation or a manual operation release according to an operation of the manual operation switch, and the operation control unit performs the manual operation. The lightning protection system according to any one of claims 1 to 5, wherein the state switch is switched to the lightning-resistant state when instructed, and the state switch is switched to the normal state when manual operation cancellation is instructed. . The operation control means is configured to switch the state changeover switch to the lightning proof state, and / or to receive a manual lightning stop instruction until a predetermined lightning proof maintenance period has elapsed since the detection of the precursor phenomenon. 7. The lightning protection system according to claim 6, wherein an operation for switching to a normal state is not performed. The lightning proof system according to any one of claims 1 to 7, wherein the lightning proof system is used by being arranged in a power supply line entrance.

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