Electric Field Detection System

Abstract

To enable detection of an electric field state with high accuracy and at low cost.SOLUTION: An electric field detection system 12 includes a field effect transistor 15, an antenna 16 connected to a gate electrode 15a of the field effect transistor 15, and a bias power source 17 to supply predetermined electric voltage V1 between a source electrode 15b and a drain electrode 15c of the field effect transistor 15. The antenna 16 is a body metal part 11a of a vehicle 11.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electric field sensing system. [Background technology]

[0002] For example, a stable power supply is necessary in facilities that require stable operation, such as semiconductor manufacturing plants. However, the reality is that natural phenomena such as lightning strikes can damage power lines and other power equipment, and power problems such as blackouts and voltage drops (momentary voltage drops) inevitably occur.

[0003] Here, a system for predicting the occurrence of lightning strikes and issuing a warning to the facility is described in Patent Document 1. More specifically, in the system described in this patent document, a lightning strike detection device is installed at the construction work site of a structure such as a tower or at a location in the vicinity of the construction work site, and an electrostatic field detection device is installed at the construction work site of the structure or at a location nearby the construction work site. The lightning strike detection device detects the occurrence of a lightning strike, and the electrostatic field detection device detects the electric field strength of the electrostatic field between the cloud and the ground. Based on the levels of the detection signals output from both detection devices, a warning output device determines the rank of warning information, and outputs the ranked warning information from the warning output device. In this case, the detection level of the electrostatic field detection device is given priority to output the warning information. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-250211 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a manufacturing factory, various installed devices are highly electrically controlled and electrically networked, so that measures against indirect damages caused by power outages and voltage drops, as well as direct damages such as damage to devices caused by lightning strikes on the facility (lightning damage countermeasures), are important. Semiconductor factories are particularly susceptible to the above-mentioned effects, and therefore require more accurate lightning strike predictions than ever before. For example, in order to improve the accuracy of lightning strike predictions in the system described in Patent Document 1, it is conceivable to increase the number of electrostatic field detectors and install them over a wide area, but the more the number is increased, the higher the equipment costs will be, so it is not realistic to provide lightning strike predictions to other parties (factories, etc.) as a paid service.

[0006] The problems mentioned above do not only apply to lightning strike prediction, but may also occur when predicting other phenomena that could become natural disasters from the state of an electric field.

[0007] In view of the above circumstances, the technical problem to be solved in this specification is to enable detection of the state of an electric field with high accuracy and at low cost. [Means for solving the problem]

[0008] The above-mentioned problems are solved by an electric field detection system according to the present invention, which includes a field effect transistor, an antenna connected to a gate electrode of the field effect transistor, and a bias power supply for applying a predetermined voltage between a source electrode and a drain electrode of the field effect transistor, and is characterized in that the antenna is a metal part of the body of the vehicle.

[0009] In the electric field detection system according to the present invention, the state of the electric field can be detected by utilizing the characteristics of a field effect transistor in which the current flowing between the source electrode and the drain electrode varies depending on the magnitude of the voltage applied to the gate electrode. That is, in this electric field detection system, the antenna receives the electric field in the space in which the antenna is placed, and a voltage corresponding to the state of the received electric field (strength, direction, etc. of the electric field) is applied to the gate electrode. Since a certain correlation is observed between the state of the electric field and the voltage (gate voltage) applied to the gate electrode, the state of the received electric field can be accurately detected by accurately evaluating the current fluctuation between the source electrode and the drain electrode that occurs when the above voltage is applied to the gate electrode. In addition, in the present invention, the antenna is the body metal part of the vehicle, so that the electric field can be detected over a very large area. Therefore, the state of the electric field can be detected with high sensitivity, and the occurrence of a lightning strike can be predicted with high accuracy. In addition, the field effect transistor is very cheap and easy to obtain, and by using the body metal part of the vehicle as an antenna, the effort and cost of preparing a separate antenna can be reduced. In addition, since the bias power supply can use an existing power supply installed in the vehicle, the detection system can be constructed at low cost in this respect as well. As described above, according to the present invention, it is possible to detect the electric field around a vehicle with high accuracy and at low cost.

[0010] The electric field detection system according to the present invention may further include a measuring device for measuring the magnitude of a current flowing between the source electrode and the drain electrode. In this case, the electric field detection system may be configured to calculate the electric field strength in the space in which the antenna is placed based on the magnitude of the current measured by the measuring device.

[0011] As described above, by directly measuring the magnitude of the current between the source electrode and the drain electrode and calculating the electric field strength based on the measured current magnitude, it is possible to evaluate the electric field state with greater accuracy and use this to predict lightning strikes.

[0012] In the electric field detection system according to the present invention, the gate electrode may be connected to one side in the up-down direction of the body metal part.

[0013] In the electric field near the ground surface where the vehicle is installed, a vertical bias of electric charge occurs. Furthermore, the bias of electric charge is promoted during lightning strikes, and the bias of electric charge may be reversed up and down depending on the season. In consideration of these phenomena, the above-mentioned bias of electric charge can be detected with high sensitivity by connecting the gate electrode to one side in the vertical direction of the body metal part that serves as an antenna. This makes it possible to detect the electric field stably and with high accuracy.

[0014] In addition, in the electric field detection system of the present invention, when the magnitude of the current measured by the measuring device is equal to or greater than a preset threshold value, information regarding the detected electric field may be transmitted using a communication system provided in the vehicle.

[0015] In this way, a threshold is set in advance for the magnitude of the measured current, and when the magnitude of the measured current is equal to or greater than the threshold, information regarding the detected electric field can be transmitted using a communication system installed in the vehicle, making it possible to use information obtained by measurement only when there is an abnormality (for example, when a thundercloud is approaching) to predict lightning strikes. Effect of the Invention

[0016] As described above, the electric field detection system according to the present invention makes it possible to detect the state of an electric field with high accuracy and at low cost. This also makes it possible to realize highly accurate lightning prediction at low cost. [Brief description of the drawings]

[0017] [Figure 1] 1 is a conceptual diagram of a lightning occurrence prediction system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of a vehicle for explaining the configuration of the electric field detection system shown in FIG. [Diagram 3] 2 is a flowchart according to an example of a prediction method using the prediction system shown in FIG. 1. [Figure 4]FIG. 11 is a conceptual diagram of a power transmission accident occurrence prediction system according to a second embodiment of the present invention. [Diagram 5] 5 is a flowchart according to an example of a prediction method using the prediction system shown in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the electric field detection system according to the first embodiment of the present invention and the lightning occurrence prediction system including this detection system will be described with reference to the drawings.

[0019] 1 shows a conceptual diagram of a lightning occurrence prediction system 10 according to this embodiment. This prediction system 10 includes electric field intensity detection devices 12 as an electric field detection system provided in a plurality of vehicles 11, a vehicle position information acquisition device 13, and a data processing device 14. Each component will be described in detail below.

[0020] 2, the electric field intensity detection device 12 includes a field effect transistor (FET) 15, an antenna 16 connected to a gate electrode 15a of the field effect transistor 15, and a bias power supply 17 capable of applying a predetermined voltage V1 between a source electrode 15b and a drain electrode 15c of the field effect transistor 15. In this embodiment, the electric field intensity detection device 12 further includes a measurement device 18 for measuring the magnitude of a current I flowing between the source electrode 15b and the drain electrode 15c, and an electric field intensity calculation unit 19.

[0021] As the field effect transistor (FET) 15, as described later, any type of field effect transistor (junction type FET, MOSFET, etc.) can be used as long as the ease of flow of the current I (current amount) changes according to the magnitude of the voltage V2 applied to the gate electrode 15a, in other words, as long as the value of the current I can be converted into the voltage V2 and thus into the state of the electric field (for example, electric field strength) that can be received by the antenna 16. In this embodiment, a MOSFET is used as the field effect transistor 15.

[0022] The antenna 16 is configured to receive an electric field near the ground surface where the vehicle 11 is located, and to apply a voltage V2 corresponding to the state of the received electric field to the gate electrode 15a. For example, in this embodiment, the antenna 16 is configured so that the magnitude of the voltage V2 applied to the gate electrode 15a is proportional to the strength of the received electric field (electric field intensity).

[0023] The antenna 16 having the above-mentioned configuration is formed of a metal body part of the vehicle 11. In this embodiment, as shown in Fig. 2, the antenna 16 is formed of a door outer 11a of the vehicle 11. That is, by electrically connecting the gate electrode 15a of the field effect transistor 15 to the door outer 11a, which is a metal outer plate of the vehicle 11, by a conductor or the like, the door outer 11a can function as the main body of the antenna 16.

[0024] In this case, the connection point of the gate electrode 15a to the door outer 11a is arbitrary in principle, but considering the vertical bias of electric charges in the electric field near the ground surface, it is preferable to connect the gate electrode 15a to one side in the up-down direction of the door outer 11a. In this embodiment, as shown in Fig. 2, the gate electrode 15a is connected to the lower part of the door outer 11a.

[0025] Any power supply can be used as the bias power supply 17. For example, it is preferable in terms of cost to use an existing power supply installed in the vehicle 11, such as a power supply for the ECU of the vehicle 11.

[0026] The measuring device 18 is composed of, for example, an ammeter, and is provided at a position where it can measure the magnitude (current value) of the current I flowing between the source electrode 15b and the drain electrode 15c of the field effect transistor 15. The measuring device 18 transmits information related to the measured current value to the electric field intensity calculation unit 19. The measuring device 18 measures the current value at regular time intervals, for example. Of course, the measuring device 18 may measure each time a command is received from the data processing device 14.

[0027] The electric field strength calculation unit 19 is configured to be able to calculate the state of the electric field (here, the electric field strength) around the vehicle 11, more precisely around the antenna 16, based on information relating to the current value measured by the measurement device 18. Furthermore, this electric field strength calculation unit 19 transmits information relating to the calculated electric field strength to the data communication device 20 provided in the vehicle 11. In this case, the electric field strength calculation unit 19 may transmit information relating to all of the calculated electric field strengths to the data communication device 20, or may transmit only information relating to the electric field strength equal to or greater than a preset threshold to the data communication device 20.

[0028] The data communication device 20 is configured to be capable of transmitting at least the electric field strength data, data relating to the position information of the vehicle 11, and data relating to the acquisition time of each piece of data to the data processing device 14. Of course, data relating to weather other than the above, that is, data relating to the weather of the area where the vehicle position data is acquired, may also be transmitted, and is configured to be capable of transmitting information on phenomena generally recognized as weather information, such as temperature, humidity, amount of precipitation (amount of snowfall), area of ​​rainfall, wind speed, wind volume, and air pressure. In addition, these weather data may be data directly measured by various measuring instruments, or may be data obtained by indirect calculation from data on operations related to the natural phenomenon, such as the number of times the windshield wipers are operated.

[0029] As the data communication device 20, a wide range of existing devices capable of data communication can be applied, and for example, a data communication device dedicated to the data communication according to this embodiment may be installed and fixed in the vehicle 11 as the data communication device 20. Alternatively, a general-purpose data communication terminal such as a tablet or smartphone with a dedicated app installed may be installed in the vehicle 11 and used as the data communication device 20.

[0030] The vehicle position information acquisition device 13 is configured as a receiver of a satellite positioning system that enables communication with a satellite (positioning satellite) for a satellite positioning system such as GPS. In this case, the vehicle position information acquisition device 13 is configured as a car navigation system, for example. The vehicle position information acquisition device 13 acquires (calculates) the position of the vehicle 11 by communicating with the positioning satellite, and transmits the acquired position information of the vehicle 11 to the data communication device 20 as position data of the vehicle 11. The data communication device 20 that receives the position data is capable of transmitting the position data to the data processing device 14 together with the above-mentioned electric field strength data and weather data. Of course, the vehicle position information acquisition device 13 may be provided in the vehicle 11 as a dedicated device separate from the car navigation system.

[0031] The data processing device 14 has a data storage unit 21 and a data processing unit 22, as shown in Fig. 1, for example. Of these, the data storage unit 21 stores position data, electric field strength data, and weather data transmitted from a plurality of vehicles 11. These data are transmitted, for example, from each vehicle 11 at predetermined time intervals. Furthermore, when there is data transmitted from a source other than the vehicle 11, the data is stored in the data storage unit 21. In the example shown in Fig. 1, weather data provided by a weather information providing agency 23 is received and stored in the data storage unit 21. This weather data includes, for example, data related to an actual lightning strike (such as area, time, and strength).

[0032] The data processing unit 22 executes a process for predicting the occurrence of a lightning strike based on various data transmitted by the data communication device 20 and stored in the data storage unit 21 .

[0033] Here, the lightning strike occurrence prediction process (specifically, execution of a program for predicting the occurrence of a lightning strike) can be performed using, for example, AI (artificial intelligence). Specifically, first, various data stored in the data storage unit 21 are used as teacher data, and the data processing unit 22 generates a learning model that outputs information on the area, time, and strength of the lightning strike (learning model generation step P1). At this time, the position data and electric field strength data of each vehicle 11, and data on the lightning strike that actually occurred (hereinafter simply referred to as lightning strike data) are used as the teacher data used. In other words, the position data and electric field strength data corresponding to the past lightning strike data, that is, the electric field strength data in the area and time when the lightning strike actually occurred, are extracted from the various data stored in the data storage unit 21 by using the corresponding position data. Then, a learning model is generated that uses the extracted electric field strength data and other weather data as inputs and outputs lightning strike data. For the lightning strike data, for example, data on the lightning strike that occurred in the past among the weather data provided by the weather information providing agency 23 can be used as shown in FIG. 1.

[0034] After generating a learning model for the occurrence of lightning strikes in this manner, the occurrence of lightning strikes is predicted using this learning model (lightning strike occurrence prediction step P2). Specifically, the data processing unit 22 executes a program that inputs the position data of each vehicle 11, electric field intensity data, and other meteorological data into the learning model generated in the learning model generation step, and outputs at least one of the area, time, and intensity of the lightning strike as a predicted result of the occurrence of the lightning strike. This obtains information about the predicted result of the occurrence of the lightning strike.

[0035] Next, an example of a lightning occurrence prediction method using the lightning occurrence prediction system 10 configured as described above will be described with reference to Figs.

[0036] 3 shows a flowchart for explaining the procedure of a lightning occurrence prediction method using the lightning occurrence prediction system 10. As shown in this flowchart, the lightning occurrence prediction method according to this embodiment includes a first data acquisition step S1 of acquiring electric field intensity data, position data, and weather data from a plurality of vehicles 11, a second data acquisition step S2 of acquiring weather data from sources other than the vehicles 11, a lightning occurrence prediction step S3 of predicting the occurrence of a lightning strike based on the various acquired data, and a lightning occurrence prediction information provision step S4 of providing information on the lightning occurrence prediction result to necessary facilities 24 (for example, various production facilities such as semiconductor factories) based on the lightning occurrence prediction result, if necessary.

[0037] (S1) First data acquisition step In this step, position data, electric field strength data, and weather data such as temperature, rainfall, and wind speed (hereinafter referred to as first weather data for convenience) of each vehicle 11 are acquired from the multiple vehicles 11 from which data is to be acquired. Specifically, the electric field strength of the space in which the vehicle 11 is located is detected by the electric field strength detection device 12 as the electric field detection system described above, and information regarding the detected electric field strength is transmitted to the data processing device 14 as electric field strength data by the data communication device 20. Similarly, position information of the vehicle 11 acquired by the vehicle position information acquisition device 13 is transmitted to the data processing device 14 as position data by the data communication device 20. In addition, weather information detected by various sensors and the like (not shown) is transmitted to the data processing device 14 as first weather data by the data communication device 20. The data processing device 14, which has received these various data, accumulates the received various data in the data accumulation unit 21. In this way, electric field strength data and first weather data at a predetermined time in multiple locations within a predetermined area are acquired.

[0038] (S2) Second data acquisition step In this step, weather data (hereinafter, for convenience, referred to as second weather data) including data on lightning strikes that have occurred in the past within a specified area (lightning strike data) is acquired from a weather information provider 23. The data processing device 14 accumulates the acquired weather data (second weather data) such as the lightning strike data in the data accumulation unit 21. As a result, the lightning strike data at a specified time within a specified area, the electric field intensity data for the same area and at the same time, and various weather data are accumulated in the data accumulation unit 21 in a mutually associated state. Note that both the timing of the first data acquisition step S1 and the second data acquisition step S2 are arbitrary, and as shown in FIG. 3, the order in which the second data acquisition step S2 and the first data acquisition step S1 are performed is not limited.

[0039] (S3) Lightning strike prediction step In this step, the data processing unit 22 performs a process of predicting the occurrence of lightning strikes in a predetermined area based on the various data acquired in steps S1 and S2. Specifically, the data processing unit 22 executes a program that inputs various data and outputs a result of predicting the occurrence of lightning strikes. Any program can be executed here, and in this embodiment, a program for predicting the occurrence of lightning strikes using the learning model described above is executed. That is, in the learning model generation step P1, a learning model for the occurrence of lightning strikes is generated using the past electric field strength data, position data, weather data, and lightning strike data acquired in steps S1 and S2 as teacher data. Thereafter, the data processing unit 22 executes a program that inputs the electric field strength data, position data, and weather data acquired at a predetermined time into the learning model and outputs at least one of the area, time, and strength of lightning strikes that will occur after the predetermined time as a result of predicting the occurrence of lightning strikes. As a result, information on the result of predicting the occurrence of lightning strikes after the predetermined time is acquired.

[0040] (S4) Prediction information provision step In this step, information about the lightning strike occurrence prediction result acquired in step S3 is provided to the facility 24 that needs it. In this way, the lightning strike occurrence prediction information can be utilized in the facility 24 that needs it (for example, for implementing advance measures against lightning strikes, including the possibility of implementing measures).

[0041] As described above, according to the electric field intensity detection device 12 of this embodiment, the antenna 16 receives the electric field in the space in which the antenna 16 is placed, and the voltage V2 corresponding to the state of the received electric field (electric field intensity) is applied to the gate electrode 15a. Since a certain correlation is observed between the electric field intensity and the voltage V2 (gate voltage) applied to the gate electrode 15a, the electric field intensity around the vehicle 11 can be accurately detected by accurately evaluating the fluctuation of the current I between the source electrode 15b and the drain electrode 15c that occurs when the voltage V2 is applied to the gate electrode 15a. Here, by using the antenna 16 of the electric field intensity detection device 12 as the body metal part of the vehicle 11, specifically the door outer 11a, the electric field can be detected over a very large area. Therefore, the electric field intensity can be detected with high sensitivity, and it is possible to predict the occurrence of a lightning strike with high accuracy. In addition, the field effect transistor 15 is very cheap and easy to obtain, and by using the body metal part of the vehicle 11 (here, the door outer 11a) as the antenna 16, the effort and cost of separately preparing the antenna 16 can be reduced. Moreover, since the bias power supply 17 can utilize an existing power supply (such as a power supply for an ECU) installed in the vehicle 11, the electric field intensity detection device 12 can be manufactured at low cost in this respect as well.

[0042] Furthermore, according to the lightning strike occurrence prediction system 10 of this embodiment, in addition to the highly accurate electric field detection capability of the above-mentioned electric field strength detection device 12, by acquiring electric field strength data and position data from multiple vehicles 11, it is possible to acquire a large number of electric field strength data over a very wide range in a state linked to the position data. Therefore, by predicting the occurrence of a lightning strike based on this large number of electric field strength data, it is possible to perform a lightning strike prediction with much higher reliability than the conventional lightning strike warning technology. Furthermore, this position data and electric field strength data can be collected (stored) by using the data communication device 20 already installed in the vehicle 11, so it is possible to build the above-mentioned prediction system 10 without incurring a significant increase in cost.

[0043] In addition, in this embodiment, the data processing unit 22 acquires from the vehicle 11 the location data, the electric field strength data, and data regarding meteorological information for the area in which the location data was acquired, and also acquires meteorological data including data regarding lightning strikes that have actually occurred from the meteorological information provider 23. Based on the various acquired data, the occurrence of lightning strikes is predicted, thereby enabling even more accurate lightning strike predictions.

[0044] Fig. 4 shows a conceptual diagram of a power transmission accident prediction system 50 according to a second embodiment of the present invention. This power transmission accident prediction system 50 includes the lightning strike prediction system 10 shown in Fig. 1, and is capable of storing data relating to the position information of power transmission facilities provided by a predetermined data providing service organization 51 in a data storage unit 21, and is capable of executing a program for predicting the occurrence of a power transmission accident due to a lightning strike in a data processing unit 22 based on the stored position data, electric field strength data, and position data of the power transmission facilities. The functions of the data processing device 14 other than those described above, and the configuration for acquiring the electric field strength data, position data, and weather data from the vehicle 11 (the electric field strength detection device 12 as an electric field detection system, the vehicle position information acquisition device 13, and the data communication device 20) are the same as those in the first embodiment, and therefore detailed description thereof will be omitted.

[0045] 5 shows a flowchart for explaining the procedure of the method for predicting the occurrence of a power transmission accident caused by a lightning strike using the power transmission accident prediction system 50. As shown in this flowchart, the method for predicting the occurrence of a power transmission accident according to this embodiment includes a first data acquisition step S5 for acquiring electric field intensity data, position data, and first weather data from a plurality of vehicles 11, a second data acquisition step S6 for acquiring second weather data from other than the vehicles 11, a lightning strike occurrence prediction step S7 for predicting the occurrence of a lightning strike based on the various acquired data, a third data acquisition step S8 for acquiring position data of a power transmission facility, a power transmission accident occurrence prediction step S9 for predicting the occurrence of a power transmission accident based on various data including the position data of the power transmission facility, and a prediction information provision step S10 for providing information on the prediction of the occurrence of a power transmission accident to a necessary facility 24 based on the result of the prediction of the occurrence of the power transmission accident. Of these, steps S5 to S7 are the same as steps S1 to S3 in the first embodiment, so detailed explanations will be omitted.

[0046] (S8) Third data acquisition step In this step, data on the location information of the power transmission facilities, specifically, data on the location information of the power transmission lines, is acquired from a predetermined data providing service organization 51. The data processing device 14 accumulates the acquired location data of the power transmission facilities in the data accumulation unit 21.

[0047] (S9) Power transmission accident occurrence prediction step In this step, the data processing unit 22 predicts the occurrence of a power transmission accident due to the occurrence of a lightning strike in a predetermined area based on the various data acquired in steps S5, S6, and S8. Specifically, the data processing unit 22 executes a program that inputs various data and outputs a predicted result of the occurrence of a power transmission accident. Any program can be executed here. For example, after outputting a prediction result regarding the area where lightning strikes will occur using the same program as in the first embodiment, the data processing unit 22 executes a program that determines whether or not the occurrence of a lightning strike will affect the operation of power transmission equipment such as a power transmission line, in other words, whether or not lightning will strike the power transmission equipment or its surroundings, based on the output prediction result regarding the area where lightning strikes will occur and the position information of the power transmission equipment acquired in step S8. In this way, a predicted result of the occurrence of a power transmission accident due to a lightning strike is acquired.

[0048] Here, an example of the effect of the occurrence of a lightning strike on the operation of the power transmission facility is a power outage or a voltage sag in the facility 24 receiving power from the power transmission facility (power transmission line). In this case, the data processing unit 22 acquires a prediction result of the occurrence of a power outage or a voltage sag in the facility 24 due to a lightning strike by executing the above-mentioned power transmission accident occurrence prediction program.

[0049] (S10) Prediction information provision step In this step, information about the predicted result of the power transmission accident acquired in step S9 is provided to the facility 24 that needs it. In this way, the predicted information of the power transmission accident can be utilized in the facility 24 that needs it (for example, for implementing advance measures against lightning strikes, including the possibility of implementing such measures).

[0050] As described above, the power transmission accident prediction system 50 according to this embodiment can predict the occurrence of a lightning strike using data related to the power transmission facility in addition to the position data and the electric field strength data, thereby making it possible to accurately predict the possibility of lightning striking the power transmission facility or its surroundings. This makes it possible to predict the occurrence of a power transmission accident due to a lightning strike with a higher probability.

[0051] In addition, in this embodiment, by predicting the occurrence of a lightning strike using data on the location information of the power transmission line as the power transmission facility, it is possible to predict with a high degree of accuracy which power transmission line will be struck by lightning or which is most likely to affect the operation of the power transmission line. Therefore, it is possible to identify in advance the facilities where a power outage or momentary voltage drop will occur when lightning strikes a power transmission line or its surroundings, and it becomes possible to easily take measures in advance.

[0052] Of course, in the above embodiment, lightning occurrence prediction is performed using a lightning occurrence prediction system 10 equipped with an electric field strength detection device 12, so that electric field strength can be detected with extremely high accuracy, thereby enabling highly accurate lightning prediction.

[0053] Although the first and second embodiments of the present invention have been described above, the electric field detection system according to the present invention can also have configurations other than those described above without departing from the spirit of the invention.

[0054] For example, in the first embodiment, the door outer 11a, which is an outer body panel of the vehicle 11, is used as the antenna 16, but of course other parts may be used as the antenna 16. In other words, the part to be used as the antenna 16 is arbitrary as long as it is a body metal part of the vehicle 11. In addition, the antenna 16 is not limited to the body metal part, and may be, for example, a metal element among components other than the body that is connected to the body metal part without being insulated from it. In addition, the connection form between the part of the body metal part that becomes the antenna 16 and the gate electrode 15a is also arbitrary, and may be set appropriately depending on the performance required for the antenna 16.

[0055] In the above embodiment, the measurement device 18 provided in the electric field intensity detection device 12 measures the magnitude of the current flowing between the source electrode 15b and the drain electrode 15c, and the electric field intensity is calculated from the measured current value by the electric field intensity calculation unit 19 as a parameter indicating the state of the electric field, but of course other configurations are also possible. For example, a predetermined resistor may be provided between the source electrode 15b and the drain electrode 15c, the voltage across the resistor may be measured by the measurement device 18, and the electric field intensity may be calculated by the electric field intensity calculation unit 19 from the measured voltage value.

[0056] In the above embodiment, the current value between the source electrode 15b and the drain electrode 15c is measured by the measuring device 18 and the electric field strength calculation unit 19 provided in the vehicle 11, and the electric field strength is calculated from the measured current value. However, other configurations are also possible. For example, the electric field strength detection device 12 can acquire data that can calculate the electric field strength in the space around the vehicle 11 by a predetermined calculation, such as the current value measured by the measuring device 18, and transmit the acquired data to the data processing device 14, and the transmitted data can be calculated by the electric field strength calculation unit 19 incorporated in the data processing device 14.

[0057] In the above embodiment, the data processing device 14 of the lightning strike occurrence prediction system including the electric field detection system according to the present invention acquires electric field strength data, position data, and first weather data from a plurality of vehicles 11, and acquires second weather data including lightning strike data from the weather information providing agency 23, and performs lightning strike occurrence prediction based on these acquired various data. However, other forms are of course possible. For example, the data processing device 22 may perform lightning strike occurrence prediction based only on the electric field strength data and position data acquired from each vehicle 11, and the first weather data. Alternatively, the data processing device 22 may perform lightning strike occurrence prediction based only on the electric field strength data and position data acquired from each vehicle 11, and the second weather data provided by the weather information providing agency 23. Alternatively, data of a type other than the above-mentioned example data may be acquired together with the position data and electric field strength data, and lightning strike occurrence prediction may be performed based on these acquired data. In short, the type of data used for lightning strike occurrence prediction is arbitrary as long as the position data and electric field strength data of the vehicle 11 are included.

[0058] In addition, in the first and second embodiments, an example is given of the case where information regarding the predicted results of a lightning strike or power transmission accident is provided to a facility 24 that requires it, but information regarding the predicted results of a lightning strike or power transmission accident may also be provided to, for example, an electric power company that has jurisdiction over the area in which facility 24 is located.

[0059] In the above description, the electric field detection system according to the present invention is applied to a lightning strike prediction system or a power transmission accident prediction system, but the electric field detection system according to the present invention can also be applied to a system for predicting natural phenomena in which fluctuations in the state of an electric field are recognized as a sign of occurrence. Of course, the electric field detection system according to the present invention can be applied not only to prediction, but also to detecting the state of a natural phenomenon that is currently occurring from the state of the electric field. Alternatively, the electric field detection system according to the present invention can be applied to detecting or predicting various events that involve fluctuations in the state of an electric field, such as detecting accidents that involve fluctuations in the state of an electric field. [Explanation of symbols]

[0060] 10. Lightning strike prediction system 11 Vehicles 11a Door Outer 12 Electric field strength detector (electric field detection system) 13 Vehicle position information acquisition device 14 Data Processing Device 15 Field-effect transistor 15a Gate electrode 15b Source electrode 15c Drain electrode 16 Antennas 17 Bias power supply 18 Measurement Equipment 19 Electric field strength calculation section 20 Data communication equipment 21 Data Storage Section 22 Data Processing Section 23 Weather Information Providers 24 Facilities 50 Power transmission accident prediction system 51 Data provision service organization S1 First data acquisition step S2 Second data acquisition step S3 Lightning strike prediction step S4 Lightning strike forecast information provision step S5 First data acquisition step S6 Second data acquisition step S7 Lightning strike prediction step S8 Third data acquisition step S9 Power transmission accident prediction step S10: Step for providing information on the occurrence of power transmission accidents

Claims

1. A field effect transistor; an antenna connected to a gate electrode of the field effect transistor; a bias power supply for applying a predetermined voltage between a source electrode and a drain electrode of the field effect transistor, An electric field detection system characterized in that the gate electrode is connected to any location on the door outer, which is a metal part of the vehicle body, so that the door outer functions as the antenna body of the antenna, thereby making it possible to detect the electric field in the space surrounding the vehicle.

2. A measuring device for measuring a magnitude of a current flowing between the source electrode and the drain electrode, The electric field detection system according to claim 1 , configured to be capable of calculating the electric field intensity in a space in which the antenna body is placed based on the magnitude of the current measured by the measurement device.

3. 3. The electric field detection system according to claim 2, wherein when the magnitude of the current measured by the measuring device is equal to or greater than a preset threshold, information regarding the calculated electric field strength is transmitted using a communication system provided in the vehicle.

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