Lightning current estimation system

Abstract

To appropriately estimate a lightning current that is a lighting parameter on the basis of a radio wave of lightning observed by lightning location systems (LLS).SOLUTION: A lightning current estimation system associates a situation of an observed radio wave in accordance with which piece of past data the situation of the radio wave is close to from accumulation of past radio wave situations and current situations, estimates a lightning discharge path model M on the basis of an estimated radio wave situation and the accumulated current situations, derives a situation of a current of lightning that has struck the earth 4 from the radio wave of the lightning that has struck an apex 1a of a structure 1 and the lightning discharge path model M, and appropriately estimates the situation of the current of the lightning on the earth 4 where the structure 1 is installed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lightning current estimation system that can estimate the lightning current situation (current parameters) according to the actual lightning strike situation.

Background Art

[0002] As a technique for estimating the lightning charge amount and position at the time of lightning strike, a lightning location system (LLS) is used (for example, Patent Document 1). The LLS is a technique for measuring the temporal changes in the electric field and magnetic field associated with a lightning strike and extracting the position and time of the lightning strike.

[0003] Conventionally, lightning parameters (lightning currents such as peak current, current steepness, charge amount, current wave tail length, etc.) for each region where lightning strikes have been obtained using the LLS. To obtain lightning parameters, a lightning discharge path model (a model of the lightning discharge path extending upward from the lightning strike point) and actually observed radio waves are used to estimate the lightning parameters.

[0004] The intensity of the observed radio waves changes depending on the distance and environment, etc. Even when observing the radio waves of the same lightning, the estimation results of the lightning discharge path model will be different. Since the situation of the lightning parameters is greatly influenced by the characteristics of the lightning discharge path model, accurate lightning parameters (lightning current) can be obtained by constructing a lightning discharge path model that accurately estimates the nature of the lightning discharge path.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] This invention has been made in view of the above circumstances, and aims to provide a lightning current estimation system that can accurately estimate the lightning current, which is a lightning parameter, based on the radio waves of lightning observed by a Lightning Location System (LLS). [Means for solving the problem]

[0007] The present invention is a technique for estimating the current of lightning strikes on the ground by constructing a lightning discharge path model using actual structures and lightning strikes on actual structures, and correcting for the influence of known structures. For example, by accumulating past data, the technique estimates the lightning discharge path model based on which of the past data the observed radio waves are closest to, and then estimates the current on the ground for the observed radio waves based on the estimated lightning discharge path model.

[0008] To achieve the above objective, the lightning current estimation system of the present invention according to claim 1 comprises: a radio wave observation means for observing radio waves of lightning struck on a reference structure; a radio wave condition derivation means for deriving the radio wave conditions at the reference structure according to the lightning conditions; a current condition derivation means for deriving the current conditions according to the radio wave conditions derived by the radio wave condition derivation means; a current model correction means for correcting the current conditions derived by the current condition derivation means to remove the influence of the reference structure and to determine the current conditions when the lightning strikes the ground; and a current evaluation means for evaluating the current parameters of the lightning strikes the ground based on the current conditions obtained by the current model correction means.

[0009] In the present invention according to claim 1, the radio wave condition derivation means derives the radio wave condition at a reference structure according to the lightning conditions, the current condition derivation means derives the current condition according to the derived radio wave condition, the current model correction means performs a correction on the current condition to remove the influence of the reference structure to obtain the current condition in the state of lightning that has struck the ground, and the current parameters of the lightning that has struck the ground are evaluated by the current evaluation means based on the current condition.

[0010] For example, the current conditions are derived based on data obtained by measuring the current of a reference structure. Furthermore, a lightning discharge path model is constructed (estimated) through a series of functions including processing by the current model correction means (radio wave condition derivation means, current condition derivation means, current model correction means).

[0011] The estimated lightning discharge path model is applied to determine the current conditions at any given location when lightning strikes a structure other than a reference structure (any location), using the lightning's radio waves and the estimated lightning discharge path model. In other words, without using an ammeter, the current conditions at any given location can be estimated using the "lightning discharge path model" estimated from a lightning strike on a reference structure and the actual radio wave conditions.

[0012] Therefore, it becomes possible to accurately estimate the lightning current, which is a lightning parameter at ground level, based on the radio waves of lightning observed by Lightning Location Systems (LLS).

[0013] Furthermore, the lightning current estimation system of the present invention according to claim 2 is characterized in that, in the lightning current estimation system of claim 1, the radio wave condition derivation means compares the radio waves of lightning that struck the reference structure with data of numerous radio wave conditions and extracts a similar radio wave condition.

[0014] In the present invention according to claim 2, the radio waves of lightning that struck a reference structure are compared with data on numerous radio wave conditions, and the radio wave conditions that approximate the observed radio waves are closest to those of past data can be extracted (a lightning discharge path model can be estimated).

[0015] Furthermore, the lightning current estimation system of the present invention according to claim 3 is characterized in that, in the lightning current estimation system of claim 1, the current condition derivation means compares the radio wave conditions derived by the radio wave condition derivation means with a large number of current condition data measured at the reference structure and extracts an approximate current condition.

[0016] In the present invention according to claim 3, the radio wave conditions derived by the radio wave condition derivation means are compared with data of numerous current conditions measured at a reference structure, and an approximate current condition is extracted, thereby deriving a current condition corresponding to the observed radio wave conditions.

[0017] Furthermore, it is possible to calculate the current conditions corresponding to the observed radio wave conditions (construct a lightning discharge path model) based on the radio waves of lightning that struck the reference structure, as well as the specifications of the reference structure.

[0018] Furthermore, the lightning current estimation system of the present invention according to claim 4 is characterized in that, in the lightning current estimation system of claim 1, the current model correction means compares the current status derived by the current status derivation means with data of a number of current correction statuses from which the influence of the reference structure has been removed, and corrects the approximate current correction status as the current status in the state of lightning striking the ground.

[0019] In the present invention according to claim 4, the current conditions derived by the current conditions derivation means are compared with data of numerous current correction conditions from which the influence of a reference structure has been removed, and the current correction condition that approximates the current conditions in the state of lightning striking the ground is considered (corrected).

[0020] Furthermore, based on the observed radio wave conditions and the resulting current conditions (lightning discharge path model), it is possible to calculate the current correction status, taking into account the specifications of the reference structure. In addition, as an example of accumulating data for estimating the lightning discharge path model, it is possible to correct the lightning discharge path model by assuming lightning parameters for the lightning discharge path model and comparing them with the measured lightning parameters to see if they can be reproduced.

[0021] Furthermore, the lightning current estimation system of the present invention according to claim 5 is a lightning current estimation system according to any one of claims 1 to 4, characterized in that the current evaluation means evaluates at least one of the current peak value, current steepness, and wave tail length as current parameters of lightning that has struck the ground.

[0022] In the present invention according to claim 5, at least one of the current peak value, current steepness, and wave tail length can be evaluated.

Effect of the Invention

[0023] The lightning current estimation system of the present invention can accurately estimate the lightning current, which is a lightning parameter, based on the radio wave of the lightning observed by a lightning location system (LLS) according to the actual lightning situation.

Brief Description of the Drawings

[0024] [Figure 1] It is a conceptual diagram for explaining the overall configuration of a lightning current estimation system according to an embodiment of the present invention. [Figure 2] It is a block configuration diagram of a lightning current estimation system according to an embodiment of the present invention. [Figure 3] It is a graph showing an example of the electric field of lightning striking a structure. [Figure 4] It is a graph showing an example of the electric field data of lightning striking a structure. [Figure 5] It is a graph showing the current situation estimated based on the data shown in FIG. 4. [Figure 6] It is a graph showing the current situation estimated based on the data shown in FIG. 4.

Modes for Carrying Out the Invention

[0025] Based on FIG. 1, the overall configuration of the lightning current estimation system will be described. FIG. 1 shows a conceptual situation for explaining the overall configuration of a lightning current estimation system according to an embodiment of the present invention.

[0026] As shown in the figure, the lightning current estimation system is equipped with a Lightning Location System (LLS). Specifically, the radio waves from lightning that strikes the top 1a of a reference structure (such as a transmission tower) 1 are measured by the radio wave measurement means 2. The information measured by the radio wave measurement means 2 is input to the control means 3.

[0027] Structure 1 is equipped with means for measuring electric current, and the electric current from lightning that struck the top 1a of structure 1 is measured and stored as data.

[0028] In the control means 3, the lightning conditions on the ground 4 where the structure 1 is installed are derived based on the information measured by the radio wave measurement means 2. In other words, the conditions of the lightning that struck the ground 4 are derived from the actual lightning conditions on the structure 1 (the point of impact being the top 1a of the structure 1), and the lightning current on the ground is estimated based on the actual lightning conditions.

[0029] The block configuration of the control means 3 and the current estimation status will be explained based on Figures 2 to 6.

[0030] Figure 2 shows the block configuration of a lightning strike current estimation system according to one embodiment of the present invention, Figure 3 shows a graph representing an example of the electric field of lightning struck on structure 1, Figure 4 shows a graph representing an example of data for the electric field of lightning struck on structure 1, Figure 5 shows a graph representing the current situation at structure 1 and the ground 4 estimated based on the data shown in Figure 4 when the rise time is fast, and Figure 6 shows a graph representing the current situation at structure 1 and the ground 4 estimated based on the data shown in Figure 4 when the rise time is slow.

[0031] The configuration of the control means 3 will be explained based on Figure 2.

[0032] As shown in the figure, the control means 3 is equipped with a radio wave condition derivation means 11. The radio wave condition derivation means 11 compares the radio wave conditions (temporal changes of the electric field) of the lightning strike on structure 1 with a large number of data and extracts data with similar conditions.

[0033] The radio wave condition data extracted by the radio wave condition derivation means 11 is sent to the current condition derivation means 12. The current condition derivation means 12 compares the radio wave condition data sent from the radio wave condition derivation means 11 with a large amount of current data that has been measured and stored in advance, and extracts data for the current condition that is closest to it.

[0034] Furthermore, it is possible to construct a current model by performing calculations that take into account the height and structural specifications of structure 1, based on the radio wave conditions transmitted from the radio wave condition derivation means 11.

[0035] The current status data extracted by the current status derivation means 12 is sent to the current model correction means 13. The current model correction means 13 performs calculations and data comparisons on the current status data extracted by the current status derivation means 12 to remove the influence of structure 1, thereby determining the current status when lightning strikes the ground 4.

[0036] In other words, a series of functions, including processing by the radio wave condition derivation means 11, the current condition derivation means 12, and the current model correction means 13, are used to construct (estimate) the lightning discharge path model M (see Figure 1). Once the lightning discharge path model M (see Figure 1) is constructed, the current conditions at the ground 4 where the structure 1 is built can be determined using the information from the lightning radio wave conditions and the lightning discharge path model M (see Figure 1).

[0037] Furthermore, it is possible to construct a lightning discharge path model M (see Figure 1) by performing calculations that take into account the height and structural specifications of structure 1, based on accumulated data such as the radio wave conditions of the lightning strike on structure 1 (changes in the electric field over time) and the measured and digitized lightning current.

[0038] The lightning discharge path model M (see Figure 1), estimated using structure 1, is applied when determining the earth current when lightning strikes a structure other than the reference structure 1 (any location). In other words, by using the radio waves from lightning that strikes any location and the estimated lightning discharge path model M (see Figure 1), it is possible to determine the current situation when lightning strikes the earth at any location.

[0039] In other words, without using an ammeter, it is possible to estimate the current conditions at any given location on the ground based on the "lightning discharge path model M (see Figure 1)" estimated from a lightning strike on structure 1 and the actual radio wave conditions.

[0040] The current conditions corrected by the current model correction means 13 are sent to the current evaluation means 14, which evaluates the current conditions of the lightning strike on the ground 4 based on the current conditions obtained by the current model correction means 13 (evaluates current parameters). For example, the current peak value, current steepness, and wave tail length are evaluated.

[0041] This allows us to derive and evaluate the current of lightning that struck the ground 4, based on the radio waves of lightning that actually struck structure 1, as observed by the Lightning Location Systems (LLS).

[0042] The processing status (current estimation status) of the control means 3 will be explained in detail based on Figures 3 to 6.

[0043] The radio wave condition derivation means 11 detects the radio wave conditions (changes in the electric field over time) of the lightning strike on structure 1, as shown in Figure 3, in two cases: when the rise time is fast (shown by a solid line in Figure 3) and when the rise time is slow (shown by a dotted line in Figure 3).

[0044] The radio wave condition derivation means 11 stores a large amount of data on the radio wave conditions (temporal changes of the electric field) associated with lightning. The radio wave conditions shown in Figure 3 (actual temporal changes of the electric field) are then compared with the data on the numerous radio wave conditions, and data that closely resembles the conditions in Figure 3 are extracted, as shown in Figure 4, in cases where the rise time is fast (shown by a solid line in Figure 4) and cases where the rise time is slow (shown by a dotted line in Figure 4).

[0045] In other words, the radio wave condition derivation means 11 compares a large amount of data on the radio wave conditions of lightning (changes in the electric field over time) with the actual measurement results, and extracts data that is close to the actual measurement results as shown in Figure 4.

[0046] The current status derivation means 12 stores a large amount of current data, which is pre-measured from the current of lightning that struck structure 1. Specifically, it stores a large amount of data on the current status of lightning at structure 1 and the ground 4 when the rise time is fast, and data on the current status of lightning at structure 1 and the ground 4 when the rise time is slow.

[0047] In the current status derivation means 12, the radio wave status data (data shown in Figure 4) sent from the radio wave status derivation means 11 is compared with a large number of current status data, and from the large number of current status data, data that is similar to the status in Figure 4 is extracted as shown in Figures 5 and 6.

[0048] Specifically, as shown in Figure 5, data on the current status of lightning at structure 1 (shown by a solid line) and ground 4 (shown by a dashed line) in a state with a fast rise time is extracted based on the conditions in Figure 4. Similarly, as shown in Figure 6, data on the current status of lightning at structure 1 (shown by a solid line) and ground 4 (shown by a dashed line) in a state with a slow rise time is extracted based on the conditions in Figure 4.

[0049] As shown in Figure 5, the current state of lightning at the ground 4 (shown by a dashed line) with a fast rise time is derived (corrected) from the current state of lightning at structure 1 (shown by a solid line) with a fast rise time, and this is performed by the current model correction means 13. In other words, the current model correction means 13 performs a process to correct the discharge circuit for structure 1 to a state where it has struck the ground 4.

[0050] As shown in Figure 6, the current state of lightning at the ground 4 (shown by a dashed line) with a fast rise time is derived (corrected) from the current state of lightning at structure 1 (shown by a solid line) with a slow rise time, and this is performed by the current model correction means 13. In other words, the current model correction means 13 performs a process to correct the discharge circuit for structure 1 to a state where it has struck the ground 4.

[0051] The process of correcting the discharge circuit for structure 1 to the state where it strikes the ground 4 involves, for example, removing the influence of structure 1 based on its specifications {height (H: see Figure 1) and total weight of the steel frame}, and creating a current model for the state where lightning strikes the ground 4 at the location where structure 1 is installed. Specifically, for example, based on pre-stored data, the current situation is corrected to the state represented by the dashed line in pre-stored data for the solid line in Figures 5 and 6, and this is considered the corrected state.

[0052] In other words, the current conditions derived by the current condition derivation means 12 are compared with data of numerous current correction conditions from which the influence of structure 1 has been removed, and the current correction condition that approximates the current conditions when lightning strikes the ground 4 is corrected. It is also possible to correct this by calculation.

[0053] The lightning discharge path model M (see Figure 1) is constructed (estimated) through the series of functions described above, including the processing in the radio wave condition derivation means 11, the current condition derivation means 12, and the current model correction means 13.

[0054] The current evaluation means 14 evaluates the current conditions (current conditions: current parameters) of lightning when the ground 4 is struck, based on the data shown by the dashed lines in Figures 5 and 6, based on the current conditions when the rise time is fast and when the rise time is slow. For example, at least one of the current peak value, current steepness, and wave tail length is evaluated.

[0055] Therefore, by accumulating past radio wave conditions and current conditions, a lightning discharge path model M (see Figure 1) is estimated (corresponding to the radio wave conditions) based on which of the past data the observed radio wave conditions are closest to. Based on the estimated lightning discharge path model (radio wave conditions), the current conditions when the lightning struck the ground 4 from the radio waves of the lightning that struck the top 1a of structure 1 are estimated.

[0056] Therefore, based on the radio wave conditions of the lightning that actually struck structure 1, as observed by the Lightning Location Systems (LLS), the lightning discharge path model M (see Figure 1) can be estimated, and the current conditions of the lightning that struck the ground 4 can be derived, allowing for an accurate estimation of the current conditions of the lightning on the ground 4 where structure 1 is installed.

[0057] As mentioned above, by estimating the lightning discharge path model M (see Figure 1), when lightning strikes a structure other than the reference structure 1 (any location), by measuring the radio waves of the lightning that struck the arbitrary location, it is possible to determine the current conditions (current parameters) as if the lightning had struck the ground at any arbitrary location, without using an ammeter at that location, by using the radio waves of the lightning that struck the arbitrary location and the estimated lightning discharge path model M (see Figure 1). [Industrial applicability]

[0058] This invention can be used in industrial fields for systems that provide information based on lightning. [Explanation of symbols]

[0059] 1 structure 2. Radio wave measurement means 3. Control means 4 earth 11. Means for deriving radio wave conditions 12 Current status derivation means 13 Current Model Correction Means 14 Current evaluation means

Claims

1. A radio wave observation device for observing radio waves from lightning strikes on a reference structure, A means for deriving the radio wave conditions at the aforementioned reference structure according to the lightning conditions, A current status derivation means for deriving the current status corresponding to the radio wave status derived by the radio wave status derivation means, A current model correction means performs a correction on the current conditions derived by the current conditions derivation means to remove the influence of the reference structure and obtains the current conditions in the state of lightning striking the ground, The system includes a current evaluation means that evaluates the current parameters of lightning that has struck the ground, based on the current state obtained by the current model correction means. A lightning strike current estimation system characterized by the following features.

2. In the lightning current estimation system described in claim 1, The aforementioned radio wave condition derivation means is The radio waves from lightning strikes the aforementioned reference structure are compared with data from numerous radio wave conditions, and similar radio wave conditions are extracted. A lightning strike current estimation system characterized by the following features.

3. In the lightning current estimation system described in claim 1, The current status derivation means is, The radio wave conditions derived by the radio wave condition derivation means are compared with data on numerous current conditions measured at the reference structure, and similar current conditions are extracted. A lightning strike current estimation system characterized by the following features.

4. In the lightning current estimation system described in claim 1, The current model correction means is The current conditions derived by the current condition derivation means are compared with data of numerous current correction conditions from which the influence of the reference structure has been removed, and the current correction condition that approximates the current conditions is corrected as if lightning had struck the ground. A lightning strike current estimation system characterized by the following features.

5. In the lightning current estimation system according to any one of claims 1 to 4, The current evaluation means is As current parameters for lightning that has struck the ground, evaluate at least one of the following: current peak, current steepness, and wave tail length. A lightning strike current estimation system characterized by the following features.

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