JPH07146377A - Device for detecting approaching of thunderbolt falling point - Google Patents

Abstract

PURPOSE:To output the information about approaching thunderbolts as thunderbolt falling approaching warnings in stages with stable accuracy by catching atmospheric phenomena associated with the thunderbolts with a detector having a special structure. CONSTITUTION:A corona current is continuously measured by providing a detector 1 equipped with an electrode plate 59 composed of a semispheric electrode, etc., and insulated needle electrodes 53 elongated in the radial direction on the top of a ground pole and connecting a detector 5 for detecting abrupt changes of electric fields to the electrode plate 59 and a DC amplifier 7 and meter relay type microammeter 8 (a circuit for detecting abrupt inversion of polarity and values of corona currents) to the needle electrodes 53. A device for detecting approaching of thunderbolt falling points outputs thunderbolt falling approaching warnings in stages in case the value of the corona current or the variation of the value of corona current before and after the abrupt change of the polarity of the corona current meets a preset criterion when the polarity of the corona current is abruptly inverted, associated with an abrupt change of the electric field. It is recommendable to connect in parallel two DC amplifiers 7 and meter relay type microammeters 8 to each needle electrode 53 so as to continuously measure the corona current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning strike point proximity detection device for knowing a remarkable approach of a lightning strike point. The present invention can be most effectively used in a signal line including a weak electric device such as a computer or in a case where the power supply is cut off to prevent the device from being destroyed by a lightning strike. These devices may be inconvenient if you cut them too early, and it is often desirable to cut those lines just before the time when the danger of receiving a lightning strike is imminent, without cutting to the limit.

[0002]

2. Description of the Related Art A device for measuring a corona current and issuing a lightning strike warning is disclosed in Japanese Patent Application Laid-Open No. 54-131986.
In this specification, regarding the relationship between the corona current flowing from the needle end of the protruding conductor and the ground electric field strength, E ⁰ = Ah ^−B E ⁰ : Ground electric field strength at the start of corona discharge. h: Ground height of the needle end (m). A, B: Constants determined by the radius of curvature ρ of the needle end and the like. After confirming that the following formula can be applied in field and indoor experiments, a current detection is provided that has a protruding conductor with a height dimension corresponding to the electric field strength on the ground and detects a corona discharge current generated in the protruding conductor above a certain value. A lightning warning device, which is characterized in that a warning signal such as a lamp or a buzzer is activated by providing a part and detecting current from the parts,
Since two different ground electric field strengths can be detected by setting up a protruding conductor, it is possible to use the higher side of the protruding conductor as a lightning warning and the lower side of the protruding conductor as a lightning warning, for example. It is proposed that this is possible. Further, Graph 1 "Ground electric field strength" of the specification describes that lightning strike occurs when the ground electric field is rapidly reversed.

However, according to many years of research by the present inventor,
It was found that lightning does not always occur if the electric field strength near the surface of the earth is large. The reason is that there is a space charge between the thundercloud's cloud bottom and the ground surface, which has a polarity opposite to that of the cloud bottom charge, and the electric potentials of the cloud bottom and the ground surface are affected by the space charge. The slope of the cloud bottom potential is affected by space charge,
It is stronger than the ground potential. In addition, the fact that the atmospheric pressure becomes lower as it gets higher in the sky also causes the lightning leader to start from the bottom of the cloud in general. On the other hand, on the ground surface, the electric field strength is hindered by space charge even immediately before a lightning strike, and the ground surface electric field does not become so strong at about 10 Kv / m. Further, the above disclosed technology is marked with a mark that a ground discharge (lightning strike) occurs when a sudden change in the surface electric field occurs.
However, the disclosed technology does not disclose anything about the distance from the observation point, that is, the determination factor of whether or not it is a lightning strike. The present invention addresses this problem and makes it possible to determine not only that the lightning strike point is approaching, but also that it is significantly approaching. That is, the present invention is not intended to detect a vague degree of proximity, but an object thereof is to provide stepwise notification from the closest lightning strike to the extremely close lightning strike.

[0004]

Generally, it is known that a charge having a polarity opposite to that of the cloud bottom is present between the thunder cloud bottom and the ground surface. If these situations are expressed using lines of electric force, it becomes as shown in FIG. In FIG. 6, + in the symbol in the cloud is the positive charge of the cloud, − is the negative charge of the cloud. (+) Indicates the space charge, +/- on the ground indicates the surface charge, and the arrow indicates the direction of the line of electric force. As described above, the electric field on the ground surface does not become so strong at about 10 Kv / m even immediately before a lightning strike. Fig. 7 shows a case of a lightning strike from the cloud, where the negative charge of the cloud decreases sharply, but the distribution of space charge does not change immediately (one part is neutralized by the discharge path during a lightning strike). . Since the ground is a conductor, a negative charge appears immediately, and the electric field on the ground surface reverses its polarity and becomes considerably strong.

Next, numerical examples will be used to specifically explain this principle. For example, the distance between the cloud floor and the earth is 1 km,
If the potential difference between the ground and the cloud bottom is about 100 million volts, and there is no space charge, then the electric field value X on the surface of the earth at this time.
Is X = 1 × 10 ^8/1 × 10 ³ = 1 × 10 ⁵ V / m. Since the actually measured value X _a is about 10 ⁴ V / m, the difference is X−X _a = 9 × 10 ⁴ V / m. Actually, since there is space charge, if the reverse electric field of the ground surface based on the space charge is _Xb , this _Xb is the above difference value 9 ×.
10 ⁴ V / m (X-X _b is the actual surface electric field value X
_a ). Therefore, if there is a lightning strike in the vicinity and the electric charge of the overhead cloud becomes almost zero, most of the space charge is left behind for a moment, and the reverse electric field X _{b of the} ground surface based on the space charge is approximately 9 × 10 in the opposite direction. ^The value is close to ⁴ / m. Therefore, a considerably strong electric field in the opposite direction is generated. Actually, the (-) charge at the bottom of the cloud is not completely zero, and the space charge is partially neutralized, so that _Xb becomes slightly smaller than the calculated value.

Next, with the passage of time, the (-) charge at the bottom of the cloud increases, and the space charge temporarily decreases due to diffusion or absorption on the ground surface, so that the value of _Xb gradually decreases,
Return to the value just before the lightning strike through the zero value. At this point, to increase again by the corona discharge generated from such plants and buildings of the space charge is also ground surface, the value of X · X _b · X _a is also considered to return to the state before lightning. For example, when the electric field value is X, the corona current I is I = K (X−X _a ) ² . X _a: electric field value corona current is generated K: coefficient Accordingly, even when measuring the corona current by using a corona needle, corona current I _b immediately after a lightning strike in lightning close range
It is seen to be much greater in the opposite polarity to the corona current I _a lightning immediately before.

The present invention does not detect all the relatively small sudden reversals of the ground surface electric field such as a large number of inter-cloud discharges caused by the approach of a thundercloud, and do not use all of them as a judgment element for the approach of lightning. In the present invention, the rapid reversal, which is a judgment factor, is used only for a lightning strike in the vicinity. That is, the corona current is continuously measured by the corona needle electrode, and when the corona current suddenly reverses, if the corona current value before or after the sudden reversal or the width of change of the current value satisfies a preset standard, the lightning strike is close to We propose a lightning strike point proximity detection device, which is characterized by outputting alarms in stages. In FIGS. 8 and 9, assuming that I _a and I _b shown by solid lines are actual current values (flowing to the meter) [I _a ] and [I _b ] are set values of the meter, the first alarm is as shown in FIG. In the case of FIG. 9, the first alarm is _Ia > [ _Ia ] or _Ib > [ _Ib ]. The second alarm is the case of FIG. 10, and the second alarm is I _a > [I _a ] and I _b > [I _b ] at the same time. Absolute value I of the width of the abrupt inversion of corona current due to lightning strike
_It can be concluded that the larger the value of _a -I _b , the closer the central part of the electric charge of the strong thundercloud is to the position directly above the observing site. Based on such an experimental rule, an object of the present invention is to detect a state where a lightning strike approaches a close range as accurately and stepwise as possible.

[0008]

According to the present invention, an electrode plate such as a hemispherical electrode and a needle electrode extending in its radial direction and insulated are provided as a sensor on the ground. Connected to the instrument and connected to the needle electrode with a DC amplifier and a meter relay type microammeter (circuit for detecting rapid reversal of polarity and detection circuit for corona current value) to continuously measure the corona current, and with a sudden change in the electric field. When the polarity of the corona current is suddenly reversed, when the corona current value before or after the sudden reversal or the variation width of the corona current value satisfies the preset standard, the lightning strike point proximity alarm is output stepwise. Provided is a lightning point proximity detection device. In addition, two DC amplifiers and a meter relay type microammeter are connected in parallel to the needle electrode to continuously measure the corona current, and when the polarity of the corona current suddenly reverses due to a sudden change in the electric field, the corona current value before and after the sudden reversal Alternatively, there is also provided a lightning strike point proximity detection device characterized in that a lightning strike point proximity warning is output stepwise when the change width of the corona current value satisfies a preset standard. In order to detect the sudden reversal of the corona current, a meter relay type microammeter having a zero-scale center and setting needles on both the positive and negative sides or a semiconductor logic circuit instead of this is provided. The circuit for detecting the sudden reversal of the corona current further includes a relay that operates when the positive and negative currents exceed the set value, a holding circuit for holding the operation for a certain period of time, and an electric field sudden change detection. A relay that operates when the container detects a sudden change in the electric field and a holding circuit that holds the operation for a certain period of time are connected.

As described above, according to the present invention, it is possible to detect the approach of the lightning strike point by positively utilizing the influence of the space charge existing between the cloud bottom of the thundercloud and the ground surface on the surface electric field. Since it is a feature, it is greatly affected by the space charge near the electrodes. For this reason, the electrode structure of the sensor is an important issue. The electrode structure sensitive to space charges must be a multi-needle type that can obtain a large amount of corona current and must have a structure in which the corona current is not easily saturated. Therefore, in the present invention, a sensor having a special structure is provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the lightning strike point proximity detection device according to the present invention will now be described with reference to the drawings. [Embodiment 1] First, a sensor used in the lightning strike point proximity detection device shown in the embodiment of FIGS. 1 and 2 will be described with reference to FIGS. The sensor 1 is a composite sensor in which a hemispherical electrode made of metal, which is an electrode plate, is combined with a radiation type corona needle electrode via an insulator (insulator) to form an integrated sensor. The sensor 1 is attached to the tip of a pole built on the ground, and an umbrella-shaped insulator 54 is attached to the upper end of a metal tube 55 that is erected radially on a metal hemispherical electrode 59. On the surface of the small metal sphere 51 provided at its tip, a plurality of small projections 52 having a taper are radially provided, and a needle electrode 53 having a sharp tip and a constant sharpness is formed on the small projection 52. It is configured to be replaceable radially and at appropriate intervals. The group of these needle electrodes 53 is insulated from the inside of the metal hemispherical electrode 59 and is electrically connected by the conductor wire 60 to be integrated. The needle electrode 53 and the small metal ball 51 are made of metal such as stainless steel.
As for the number of needles, one unit of metal tube 55 has six needle electrodes 5
3 is provided. Since the metal hemispherical electrode 59 is provided with 5 units of the metal tube 55, a total of 30 needle electrodes 53 are radially dispersed in the space. It is expediently convenient to use a medical injection needle or a needle-like electrode similar to this (hereinafter simply referred to as an injection needle) for the needle electrode 53. Even if the small metal sphere 51 is not a perfect round sphere,
If the shape is such that a corona current does not easily occur, a sphere having a similar shape or a circular shape may be used. The small projections 52 having a taper are radially provided upright on the surface of the small metal sphere 51 at appropriate intervals. A needle electrode 53 is replaceably provided on the small protrusion 52 by screwing, fitting, or the like. Small metal ball 5
1, a female screw is erected on the lower side of the metal pipe 55, and a metal shaft 57 that is threaded at both ends penetrating the inside of the metal pipe 55 is used. Inside the hemispherical electrode 59, it is tightly fastened to the upper end of the metal tube 55 by a nut 58. In this way, the hemisphere and the plurality of metal tubes 5 radially protruding from the hemisphere at equal intervals.
5, a metal hemispherical electrode 59 having the above-mentioned shape is used.
Small metal spheres 51 are attached with sandwiching them, and a plurality of predetermined needle electrodes 53 are radially attached to the small metal spheres 51, and they are integrally connected by conductors inside the hemispherical electrodes. In addition, the insulator 54 having a specific shape is a raindrop-shaped umbrella as shown in FIG. 4 in order to maintain high insulation against rain so that the insulation does not decrease during rain and the measured current does not decrease. It is made of porcelain or resin with a mold-shaped head. Further, a medical injection needle is used for the needle electrode 53, and a small metal projection 52 having a tapered shape is embedded in the surface of the small metal sphere, and the small metal sphere 52 can be interchangeably used by fitting it.

The sensor / composite type sensor having such a structure has the following advantages. (1) Generally, at the initial stage when the corona current flows out,
Although the operating state is unstable, the whole corona current value is averaged due to the multi-needle type, and a constant state is always obtained. (2) Since the sensor is used outdoors for a long time, the corona needle electrode may be damaged by birds and insects. Does not affect (3) When detecting a sudden change in electric field with a hemispherical metal electrode,
When a strong electric field is directly acting, it may give a false alarm even if there is no sudden change in the electric field due to collision of raindrops or snowflakes. Since the corona needle electrode is arranged on the periphery of the hemispherical electrode plate surface evenly, the metal hemispherical electrode is not directly exposed to the strong electric field, so that the above-mentioned false alarm can be avoided. (4) When the center of the thundercloud approaches the sensor, a large amount of ions are emitted from the radial multi-needle type electrode, which compensates the action of the space charge described above, so that the approach of the lightning strike can be detected more effectively. You can (5) When a thundercloud with a strong electric charge comes onto the sensor, a large amount of ions are emitted from the composite sensor, so that it is possible to prevent the risk of direct lightning strikes on the sensor. (6) Since the needle electrode uses a medical injection needle, it is possible to use an inexpensive and highly uniform product. (7) Since the needle electrode is attached so that it can be replaced, it can be easily replaced at any time, so the reliability as a sensor is high.

FIG. 1 is a block connection diagram of an embodiment of a lightning strike point proximity detection apparatus using the sensor 1. First, the reference numerals of the blocks will be listed and described. 5 is a sudden electric field change detector, 6 is a holding circuit (recovery time 0, 1 to 0.5 seconds),
Reference numeral 7 is a DC amplifier, 8 is a zero scale at the center, and a meter relay type microammeter (see FIG. 5) having positive and negative setting hands at both ends of the pointer, 9 is a positive current contact connected to the microammeter, and 10 is Similarly, a negative current contact 11 is a holding circuit for the positive current contact 9 (recovery time 0, 1 to 0, 5
Approximately seconds), 12 is a holding circuit for the negative current contact 10 (recovery time is approximately 0.1 to 0.5 seconds, similarly to the above), 13, 14,
Reference numeral 15 is an AND circuit, 16 is an OR circuit, 17 is a first lightning strike approach warning, and 18 is a second lightning strike approach warning.

In the apparatus of the embodiment, a pole is built on the ground, and the sensor 1 = composite sensor is insulated and fixed to the tip of the pole, and a sudden change in electric field is applied to the metal hemispherical electrode 59 of the sensor 1. The detector 5 and the holding circuit 6 are connected, and the DC electrode 7 and the meter relay type microammeter 8 are connected to the needle electrode 53 group.
(Detection circuit for sudden reversal of polarity and detection of corona current value) is connected. The ground side of the sudden electric field change detector 5 and the DC amplifier 7 is connected to the ground electrode 4. The electric field sudden change detector 5 is
Decrease the sensitivity as much as possible and detect only sudden changes over a specified width. The meter relay type microammeter 8 has a positive current contact 9 which is turned on and off depending on whether a preset positive current value is exceeded and its holding circuit 11, and a negative current which is turned on and off depending on whether a preset negative current value is exceeded. The current contact 10 and its holding circuit 12 are connected. As described above, the holding circuit 6 operates by the output signal of the electric field sudden change detector 5, the holding circuit 11 operates in conjunction with the positive current contact, and the holding circuit 12 operates in conjunction with the negative current contact. Is configured. Detection signals from the holding circuit 6 and the holding circuit 11 are connected to the AND circuit 13, and the holding circuit 6 and the holding circuit 1 are connected.
The detection signal from 2 is connected to the AND circuit 14, and the detection signals of the holding circuits 11 and 12 are connected to the AND circuit 15. Further, the AND circuit 13 and the AND circuit 14
Is connected to the OR circuit 16 to catch one of the signals and activate the first lightning strike approach warning 17
When both the positive and negative current values of the D circuit 15 exceed the set current values, the second lightning strike approach alarm 18 is instructed to operate. In this way, when the polarity of the corona current is suddenly reversed due to a sudden change in the electric field, a lightning strike point proximity warning is issued when the corona current value before or after the rapid reversal or the change width of the corona current value satisfies a preset standard. Output in stages.

FIG. 5 is a perspective view of the meter relay type microammeter 8. In FIG. 5, p is a meter 8
Pointer, r is the positive setting needle, g is the negative setting needle, R is the positive setting needle r
Adjusting knob for G, and G for adjusting knob for negative setting needle g, P
Is a zero position fine adjustment screw of the pointer p of the meter 8.

A typical operation example of the lightning strike point proximity detection device of the present invention will be described with reference to the graph of FIG. 8 showing the passage of time on the horizontal axis and the change on the corona current on the vertical axis. First, the microammeter 8 will be described. Since the pointer p is above the negative setting needle g, the negative current contact 10 is ON. The corona current reverses with a change in polarity due to a nearby lightning strike, but the change width is rather small, so the pointer p of the microammeter 8 cannot exceed the positive setting needle r. However, on the other hand, when there is an output signal of the electric field sudden change detector 5 at the same time as a lightning strike, and this signal is input while the holding circuit 11 is operating, in the case of the graph of FIG. 9 in which the AND circuit 14 operates. Then, the microammeter 8
The pointer p does not exceed the negative setting needle g immediately before the lightning strike, but exceeds the positive setting needle r immediately after the lightning strike, so the positive current contact 9 is turned on. The output signal from the sudden electric field change detector 5 is output immediately before that, but since the holding circuit 11 is operating, the AND circuit 13 operates. AND circuit 1 described above
Since 3 and the AND circuit 14 are connected to the OR circuit 15, the first lightning strike approach alarm 17 is output even when one of the AND circuit 13 and the AND circuit 14 operates. The graph of FIG. 10 is an example of the most curved and closest lightning strike, and the pointer p of the microammeter 8 is first displayed.
Is above the negative current setting hand g, the negative current contact 10 is ON immediately before a lightning strike. Immediately after the lightning strike, the pointer p suddenly reverses to exceed the positive setting hand r, and at the same time, the positive current contact 9 is turned on. Since the holding circuit 11 is connected to the negative current contact 10, the negative current contact 10 is not turned off yet at the moment of a lightning strike, and the positive and negative current contacts 9 and 10 are connected.
Are ON at the same time, the AND circuit 15 operates,
The second lightning strike approach alarm 18 is output. The meter relay 8 may be replaced with a semiconductor type logic circuit.

The signal obtained by such a lightning strike point proximity detection device is specifically connected to the equipment as follows. a) The alarm device operates and issues an alarm for a certain period of time. b) The alarm signal is sent to the relay and used for automatic control such as shutting off the power supply circuit or the signal circuit for a certain period of time. The lightning strike point proximity detection device of the present invention provides a lightning strike proximity warning step when the corona current suddenly reverses as described above and when the corona current value before or after the rapid reversal or the range of change in the current value satisfies a preset reference. It is possible to accurately output a lightning approach warning at an extremely short distance by setting the setting criteria obtained by taking into consideration the weather conditions and empirical rules peculiar to each region.

[Embodiment 2] FIG. 2 shows a meter relay type microammeter 8 · 8 set with different set values.
FIG. 3 is a block connection diagram of an embodiment apparatus in which two a's are provided side by side so as to issue a lightning strike point proximity warning in four stages. A pole is built on the ground, and the sensor 1 = composite type sensor is insulated and fixed to the tip of the pole, and the metal hemispherical electrode 59 is connected to the ground electrode 4 by the resistor 3 having a high resistance value. In addition, the lead wire 60 in which a large number of needle electrodes 53 are gathered together includes a DC amplifier 7, a meter relay type microammeter 8 (a circuit for detecting a sudden reversal of polarity and a detection circuit for positive and negative current values), and a meter relay type microammeter 8a (a rapid polarity meter). Corona current is continuously measured by connecting two of (reversal detection and 0 current and positive current value detection circuit) in parallel.

Meter relay type microammeter 8a
In (Fig. 11), ON / OFF at the set positive current value (large)
The positive current contact 20 and the holding circuit 24 are connected, and the zero current contact 21 is connected. The other meter relay type microammeter 8 (Fig. 12) has a positive current contact 22 that turns on / off at a set positive current value (small) and a negative current that turns on / off at a set negative current value (large). Contact 23
And the holding circuit 25 are connected.

The positive current contact 20 and the negative current contact 23 are ORed together.
A first alarm 32 is connected which is connected to the circuit 30 and which, if any of these signals is input, gives an alarm for a certain period of time. The 0 current contact 21 and the holding circuit 24 are connected to the AND circuit 26, and the 0 current contact 21 and the holding circuit 25 are
The AND circuit 26/27 is connected to the ND circuit 27, the AND circuits 26 and 27 are connected to the OR circuit 31, and the second alarm 33 that outputs an alarm for a certain period of time when any of these signals is input is connected. The positive current contact 22 and the holding circuit 25 are connected to the AND circuit 28, and when these signals are simultaneously output, the third alarm 34 is output for a certain period of time. The holding circuit 24 and the holding circuit 25 are connected to an AND circuit 29, and are connected to a fourth alarm 35 that outputs for a certain period of time when both positive and negative current values exceed a set value (large-large).

By connecting the two meter relay type microammeters 8 and 8a in parallel, it is possible to grasp the change in the corona current in detail and inform that the approaching distance is close to four steps.

[0021]

As described above, according to the lightning strike point proximity detection device of the present invention having such a configuration, it is possible to utilize the simple phenomenon of sudden reversal of the ground surface electric field caused by the action of space charge, It is possible to accurately detect, step by step, the remarkable approach of a lightning strike point, which is difficult to know with the five senses. When used as a lightning protection measure for weak electric appliances such as computers, it is possible to turn off the power supply circuit immediately before a lightning strike at the observation site without cutting off the power supply or signal circuit very early without cutting off the power supply or signal circuit very soon. It should be a useful invention.
In addition, since it can detect the shortest distance stepwise, it can be applied to various notifications and appropriate control of equipment during a lightning strike.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing an embodiment of a lightning strike point proximity detection device according to the present invention.

FIG. 2 is a block connection diagram showing another embodiment of the lightning strike point proximity detection device according to the present invention.

FIG. 3 is a front view of a sensor used in the lightning strike point proximity detection device according to the present invention.

FIG. 4 is a partial cross-sectional view of an insulator also used in the sensor.

FIG. 5 is a perspective view of a meter relay type microammeter used in the lightning strike point proximity detection device according to the present invention.

FIG. 6 is a diagram showing the relationship between the cloud bottom of a thundercloud and the ground surface potential, space charge, etc., using lines of electric force.

FIG. 7 is a diagram similarly showing how the situation of FIG. 4 changes due to a lightning strike (ground discharge) by lines of electric force.

FIG. 8: When a lightning strike occurs at a close range, a large change in corona current occurs with a sudden polarity reversal. The vertical axis shows the polarity and magnitude of the corona current, and the horizontal axis shows the elapsed time (t. ) Is a graph showing that, although the polarity is reversed by a lightning strike at a point slightly distant from the observation point, the change width of the corona current is small, and I _a immediately before the lightning strike is smaller than I _b immediately after the lightning strike. The graph that shows.

FIG. 9: When a lightning strike occurs at a close range, a drastic change in the corona current occurs with the polarity reversing. The vertical axis shows the polarity and magnitude of the corona current, and the horizontal axis shows the elapsed time (t. ), The change width accompanying a sudden reversal of polarity is small, and the size of the change width is almost the same as that of FIG. 8, but the corona current I _b immediately after the lightning strike is greater than the I _a immediately before the lightning strike. large.
Therefore, the graph showing that the lightning strike point is closer than that of FIG.

[Fig. 10] When a lightning strike occurs at a close range, a drastic change in the corona current occurs with the polarity reversing. The vertical axis indicates the polarity and magnitude of the corona current, and the horizontal axis indicates the elapsed time (t. ), In which I _a immediately before a lightning strike is also a set value [I _a ]
Immediately after the lightning strike, I _b also exceeds the set value [I _b ].
Therefore, a graph showing a lightning strike with a wide range of change in the current value when the lightning strike was at the closest distance.

11 is a perspective view of a meter relay type microammeter with a large positive current set value used in the embodiment of FIG. 2 of the lightning strike point proximity detection device according to the present invention.

FIG. 12 is a perspective view of a meter relay microammeter used in the embodiment of FIG. 2 of the lightning strike point proximity detection device according to the present invention, in which the positive current set value is small and the negative current value set value is large.

[Explanation of symbols]

 1 Sensor 3 Resistor 5 Electric field sudden change detector 6 Holding circuit 7 DC amplifier 8 Meter relay type microammeter 8a Meter relay type microammeter 9 Positive current contact 10 Negative current contact 11 Holding circuit 12 Holding circuit 13 AND circuit 14 AND circuit 15 AND circuit 16 OR circuit 20 Positive current contact 21 0 Current contact 22 Positive current contact 23 Negative current contact 24 Holding circuit 25 Holding circuit 26 ・ 27 ・ 28 ・ 29 AND circuit 30 ・ 31 OR circuit 17 ・ 18 ・ 32 ・ 33 ・34/35 Alarm 51 Small metal sphere 52 Small protrusion 53 Needle electrode 54 Insulator (umbrella type) 55 Metal tube 56 Insulator 57 Metal shaft 58 Nut 59 Metal hemispherical electrode (electrode plate) 60 Conductor wire

Claims (7)

[Claims] 1. An electrode plate such as an insulated hemispherical type electrode and a needle electrode are provided together as a detector on the ground, and a sudden electric field change detector is connected to the electrode plate, and a DC amplifier and a meter relay type micro are connected to the needle electrode. When the corona current is continuously measured by connecting an ammeter and the polarity of the corona current suddenly reverses due to a sudden change in the electric field, the corona current value before or after the sudden reversal or the change width of the corona current value is the preset reference value. A lightning strike point proximity detection device, which outputs a lightning strike point proximity warning stepwise when the above conditions are met. 2. A corona current is continuously measured by installing an insulated electrode plate such as a hemispherical electrode and a needle electrode on the ground, and connecting two DC amplifiers and a meter relay type microammeter in parallel to the needle electrode. In addition, if the polarity of the corona current suddenly reverses due to a sudden change in the electric field, a lightning strike point proximity warning is issued only when the corona current value before or after the rapid reversal or the width of change in the corona current value satisfies a preset standard. A lightning strike point proximity detection device characterized by outputting in stages. 3. A meter relay type microammeter having a zero scale at the center and setting needles on both positive and negative sides for detecting the sudden reversal of the corona current according to claim 1 or 2, or a semiconductor logic circuit replacing the microammeter. A lightning strike point proximity detector equipped with. 4. The circuit for detecting the sudden reversal of the corona current according to claim 1 and claim 2, further comprising a relay which operates when a positive current and a negative current exceed a set value, and a constant operation thereof. A lightning point proximity detection device to which a holding circuit for holding time, a relay that operates when a sudden change in the electric field is detected by an electric field sudden change detector, and a holding circuit that holds the operation for a certain period of time are connected. 5. A sensor having an electrode plate and a needle electrode, which are insulated from the ground according to claim 1 or 2, is made of metal having a hemispherical surface and a plurality of metal tubes radially protruding from the hemispherical surface at equal intervals. With a hemispherical electrode, a small metal ball is attached to the end portion of each of the metal tubes with a specific insulator sandwiched between them, and a predetermined number of needle electrodes radially extending from the metal ball are used as detectors. A lightning point proximity detector. 6. A lightning strike point proximity detection device, wherein the needle electrode of claim 5 is a medical injection needle that is removably attached to the small metal ball. 7. A lightning strike point proximity detection device, wherein the insulator sandwiched between the metal tube and the small metal sphere of claim 5 is porcelain or resin having an umbrella-shaped portion on its head.