The disclosure relates generally to forest fire identifications and more particularly to a novel detection system for identifying wildfire locations and powerline/power generation system damage based on lightning strike detection.
Lightning is the number one cause of wildfires in terms of area burned across the Western US where over 70% of the area is burned due to lightning-initiated fires, and in Australia where over 80% of the area burned is due lightning-initiated fires. It is also a major concern in forests and natural habitats throughout Florida, and in other parts of the world. It is costly, time consuming, and impractical to investigate each lightning strike point as a possible fire ignition location because there are millions of lightning strikes across the US each year. Many lightning-initiated fires go unnoticed for extended times and become so large that they are difficult, dangerous, and costly to suppress.
It is believed that less than 5% of the lightning strikes can ignite fires. These High-Risk-Lightning strikes tend to have long continuing-current and large charge-transfer. These two factors are directly related to heating processes during the electric discharge. Thus, they directly increase fire ignition risk. Standard lightning locating systems (“LLSs”) do not have the capability of directly measuring the duration of the lightning current or the charge transfer. LLSs map lightning in two dimensions which leads to less precise detection of lightning strike location and provides little or no information about the cloud charge structure.
Current satellite-assisted technologies rely on optical emissions from lightning strikes to determine the current duration. This involves two steps: (1) the number of subsequent frames with an image brightness above the threshold level is calculated (i.e. measure how long the lightning channel is visible on the satellite images); (2) then the satellite-based detection location is connected with the nearest ground-based detection location. Ground-based networks have less spatial error. This two-step process that relies on satellite data for current-duration information and ground-based data for location information only works when the light is not scattered by the thundercloud too much before reaching the satellite (e.g. Geostationary Lightning Mapper) sensor. When the light is scattered by the cloud, the long-continuing-current (“LCC”) is inaccurately detected (i.e. incorrect duration) or not detected at all.
Fire camera systems are being built out on a large scale to monitor forests and detect fires. However, camera systems are inefficient and slow at detecting fire ignitions because their pan, tilt, and zoom (PTZ) capabilities are usually underutilized. Operators only zoom in on fires once they spotted them on the full-scale camera image, which means that the zoom capabilities (often 60× optical zoom) are effectively unused for early fire detection.
In addition, drone fleets are being deployed both to verify fire ignitions and to aid in extinguishing the fires. Continuous monitoring of large areas is difficult and expensive. It also poses legislative concerns as aerial monitoring by numerous drones is often perceived as an invasion of privacy.
The novel system and method described herein for identifying wildfire initiation locations based on lightning strike detections is directed to overcoming, or at least reducing, the problems described above for current detection systems, as well as providing additional benefits and advantages over the above described current detection systems.
Generally disclosed is a system and method for detecting High-Risk Lightning (HRL) strikes for use in identifying possible locations (e.g. forest, etc.) for a wildfire from the HRL strike to allow for an earlier response to a wildfire by first responders (e.g. firefighters, etc.) to help maintain and/or reduce the chance of spread by the wildfire. Using the disclosed novel system and method wildfires can be detected preferably within seconds. The system and method can use a network of detectors, data from environmental satellites and/or other environmental data sources, and novel AI/algorithms for signal processing to relatively quickly locate fire ignition spots. Thus, the system and method provide for actionable wildfire intelligence in real-time and to relatively quickly and accurately send out alerts, notifications, warnings, etc. (collectively “alert” or “alerts”) when an HRL event occurs. Thus, the novel system and method allows for alerts to be sent out even before there is visible signs of a fire. This early detection and notification allow for decreases in firefighting costs, utility company losses, insurance payouts, etc.
The HRL detectors providing multiple lightning strike data feeds and the preferred AI based selection algorithm (associated with a central processing server) enable real-time HRL detection. The HRL detectors can be preferably placed 20 km apart, in the geographical area (i.e. forest, parks, jungle, etc.) to be monitored for lightning ignited fires. Though 20 km apart is preferred, such is not considered limiting and smaller and larger dimensions, such as, but not limited to 30 km apart can be used and are considered within the scope of the disclosure. The distance between the detectors chosen is preferably chosen to allow the detectors to maintain their ability to map lightning in 3D to provide for superior location accuracy, detect long-continuing current, and report electric charge transfer.
In one non-limiting embodiment, the system and method can use a multi-messenger approach where many different input data can be used to select the lightning strikes that pose a high fire risk. A relatively large set of inputs can be used to train the AI component of the system, apply lightning science, and use astrophysical selection algorithms to find High-Risk-Lightning (HRL) strikes. The novel system and method described herein provides for a major improvement over traditional lightning detectors as the system and method delivers actionable intelligence by preferably selecting those 1-5% of the strokes that present a high risk of ignition and preferably assigning a risk profile to each lightning stroke.
Though not considered limiting, the system can use the NOAA GLM lightning satellite to cross-corroborate potential fires with a real-time lightning database. The system can also use multiple bands to differentiate between regions of cloud and no-cloud to allow for higher accuracy. Though also not considered limiting, the system can scan for fires every 5 minutes. Other smaller and/or larger scanning time periods can be used and are also considered within the scope of the disclosure.
The more input the better and allows the system and method to be tailored to the intended user's needs. If some of the data fields are not available, the system and method is able to work around not having such data. Below is an indicative, though non-limiting, list for input data, though the system and method described herein can use more or less data than the data fields indicated below.
1, Lightning Data: It is preferred to have lightning parameters such as current duration, charge transfer, peak current, polarity, luminosity waveshape, electromagnetic waveshape and stroke multiplicity.
2, Weather: Temperature, precipitation, humidity, wind, insolation. The input data can have high spatial and time resolution (e.g. hourly data with 1 km resolution) and can be downloaded in real-time through an API.
3, Vegetation and Fuel: Vegetation data such as NDVI and fuel data such as the data from LANDFIRE can be used. Fuel condition data such as 1, 10, 100. 1000 hour fuel moistures, energy release components and ignition components can also be used.
4, Fire data: Real-time data and preferably also historical data. Real-time fires can be provided using GOES-16, Himawari-8, MODIS, and VIIRS. Historic data from higher resolution satellites such as LandSat can also be provided. Other sources for the real-time fire data and/or the historical data can be used and are also considered within the scope of the disclosure.
Also disclosed is a novel process for triggering fire cameras using real-time lightning data as triggers for the Pan-Tilt-Zoom (PTZ) cameras, and the data can also be used for triggering and controlling aerial drones. The PTZ cameras can be supplied with the latitude, longitude, and error ellipse for a given lightning stroke and can preferably automatically pan, tilt, and zoom to monitor the area within the error ellipse. This enables high-resolution instant monitoring. The use of the system for triggering fire cameras can be provided with two main features: (1) Lightning Data: preferably having lightning parameters including latitude and longitude of the strike point, error ellipse, and indication of intercloud (IC) vs. cloud-to-ground (CG) lightning; and (2) Pan-Tilt-Zoom (PTZ) cameras: The cameras preferably can be calibrated to a specific point, such as, without limitation, true north and they can preferably automatically zoom on the possible ignition area that corresponds to the area of the lightning error ellipse. The disclosed system and method allow for the cameras and drones to be efficiently triggered providing for better performance and utilization of the camera and/or drone systems, as compared to current use of such camera systems. The novel system and method can efficiently trigger wildfire camera systems, forest services, drones, etc.
The system and method can also be used to empower NGOs and land trusts to protect against illegal burning (i.e. those that are claimed to be lightning induced). The system also provides for real-time fire tracking, and can display a screen to allow a user to see fires that were detected by the AI of the system withing the last 24 hours (though not limiting, and other time periods, greater and smaller, can be selected and are considered within the scope of the disclosure). In one non-limiting embodiment, the use can click on one of the displayed first locations (i.e. points on a map on a computer or electronic device screen) and see more details about the particular event.
As noted above, it is believed that less than 5% of the lightning strikes can ignite fires. These HRL strikes tend to have long continuing-current and large charge-transfer. Also disclosed herein, is an HRL detector/detection system component for the overall novel system and method that can have a dual-band design that allows it to provide precise current duration and charge transfer measurements. The novel detector/detection system can be provided with three-dimensional lightning imaging capabilities, which can lead to: (1) More precise lightning localization: The lower part of the lightning channel is often not completely vertical, which means that 2D mapping takes an average of the lower part of the lightning channel and reports that as the lightning strike location. 3D mapping provided by the disclosed novel detector/detection system allows for the precise imaging of the location where a lightning stroke attaches to the ground. Precise lightning location information (preferably down to 30 meters, though not limiting) can enable fire fighters and emergency managers to efficiently navigate their crews to the potential ignition spot, and to effectively utilize camera and drone systems for fire reconnaissance; and (2) Richer information about the cloud charge structure: 3D imaging can lead to relatively richer information about the cloud charge structure that can allow for a better understanding of the type and state of the thunderstorm, and it can enable the localization of the cloud charge pockets. This can be used for nowcasting and can also reinforce the charge transfer measurements that can be used for the fire ignition risk models.
In addition, the disclosed system and method can also be used for detecting/determining High-Risk-Lightning and/or other lightning strikes directly on or affecting powerlines, power generation systems and/or other objects which can be damaged based on a High-Risk-Lightning strike. However, when using the disclosed system and method in connection High-Risk-Lightning strikes possibly damaging powerline/power generation system any underlying vegetation, weather, and environmental parameters (used in connection with wildfire determinations) is typically not needed or used. Rather, for powerline applications the detailed characteristics of the powerlines (including voltage rating, insulation level, tower geometry, and type of grounding system) can be used to determine the probability of damage from a given lightning strike. Preferably in the powerline/power generation system application, the detailed lightning strike classification (electric field profile, current duration, charge transfer) can also be used by the system to determine the risk to powerlines associated with each strike.
As seen in
The HRL lightning detector hardware system can measure the electric field waveshapes emitted by lightning strikes. The emissions from DC to 1 MHz can be recorded and digitized using/in the HRL detector system electronics preferably at a sampling rate of 6 Mega samples per second, though such sampling rate is not considered limiting and other higher and/or lower sampling rates can also be used and are considered within the scope of the disclosure. For purposes of the disclosure, this can be labeled or identified as the high-frequency (HF) channel. The HF channel can have a shorter decay time constant (e.g. 1 ms, etc.), so it can accurately detect short pulses along the lightning channel without reaching saturation. This means that the small pulses (preferably all of the small pulses) along the lightning channel can be imaged and used for creating an accurate 3D lightning map.
The detectors and associated electronics also out in the field (i.e. forest, jungle, etc.) can be powered by any conventional power source, including, without limitation, battery, rechargeable battery, solar, AC (where available), etc.
Though not considered limiting, the emissions from 20 HZ to 100 kHz can be preferably recorded and digitized in the HRL detector system electronics at a preferred sampling rate of 1 Mega samples per second (though not limiting and other higher and/or lower sampling rates can be used and are considered within the scope of the disclosure). For purposes of the disclosure, this can be labeled or identified as the low-frequency (LF) channel. The LF channel can have a longer decay time constant (e.g. 1 second, etc.), so it can accurately detect long-continuing-current (LCC) without the electric field decaying to zero. This means that the current duration and charge transfer can be calculated without the need for electric field reconstruction. In a preferred, non-limiting embodiment, the lower frequency response is determined by the time constant of the system and the upper frequency response is determined by the operational amplifier, and no filters are employed. It is also within the disclosure, that the lower frequency limit can be practically/virtually DC, and/or that the upper limit can be controlled by an integrator circuit (i.e. low-pass filter), the bandwidth of the operational amplifier used and/or the frequency response of the antenna.
The detector system also includes a front-end system (
The next stage of the HRL detector can be a Field Programmable Gate Array (FPGA) based data acquisition unit that receives the analog signals of the Radio Frequency (RF) frontend on two channels (LF and HF). The two channels can be converted to digital signals by the analog-digital-converter (ADC), preferably as a non-limiting example at 10 bits at 1 MSPS (LF), and 1-10 MSPS (HF). The electronics is not considered limited to any specific number of separate printed circuit boards. As a non-limiting example, the ADC and the frontend can be combined or otherwise provided on a single printed circuit board. Other configurations and combinations for the various electronic components in all embodiments of the systems can also be used and adopted and all are considered within the scope of the disclosure.
The data can be continuously stored into an onboard circular buffer. Once an event occurs, the received waveform (+/−0.5 sec) can be stored in random access memory (RAM) and on an SD card. Preferably, the events can be timestamped using GPS time synchronization, or other timestamping technology. The events recorded at this site and any other different sites can all be collected and/or transmitted/sent to a central server (e.g. AWS server, etc.) where the lightning analytics can be carried out.
Though not considered limiting, a high frequency range can be from 20 Hz or about 20 Hz to 2 MHz or about 2 MHz and a preferred high frequency range can be considered 40 Hz or about 40 HZ to 500 KHz or about 500 KHz. Though not considered limiting, a low frequency range can be from 0 Hz or about 0 Hz to 300 Hz or about 300 Hz and a preferred low frequency range can be considered 0 Hz or about 0 HZ to 100 Hz or about 100 Hz.
As seen in
Preferably the novel system/network and method described herein can use a large set of inputs to train the AI, apply lightning science, and can use selection algorithms to find High-Risk-Lightning (HRL). Use of finding HRL events is a major improvement over traditional lightning detection as the disclosed novel system/network and method can deliver actionable intelligence by selecting those lightning strokes that present a high risk of ignition (i.e. start of wildfire) and assigning a risk profile to each HRL. The False Alarm Rate (FAR) and False Dismissal Rate (FDR) can be optimized to meet a specific user's needs. As a non-limiting example, Florida Forest Service firefighters prefer to have the FDR close to 0%.
Non-limiting examples of lightning data that can be used as part of the AI training, as well as for use when determining a current HRL event, include:
Non-limiting examples of Environmental Data used which can be downloaded from central databases associated with the central service or third party databases, such as, without limitation, governmental database. include:
1. Weather data: Temperature (e.g. 2 m), relative humidity (e.g. 2 m), wind, insolation, cloud cover. Optimally, at least or less than 500 m spatial and 1 hour temporal resolution. Ground-based data from stations such as ASOS, FAWN, RAWS, as well as satellite-based systems such as GOES-16 are employed. Accumulated precipitation (NOAA satellite products and radar products with 1 km spatial and 5 minute temporal resolution).
2. Vegetation and Fuel: Fuel condition data such as 1, 10, 100, 1000 hour fuel moistures, 1 to 20 day soil moisture, energy release component, ignition component, burning index, drought code, duff moisture code, fire weather index, KBDI, and spread component (with available time resolution). Data from Sentinel I and II (including all 12 bands and combinations such as NBR and NDVI). Landcover data and Landfire maps are used for detailed vegetation classification. As used herein, “fuel” is referring to items and materials that can be easily ignited such as, but not limited to, dry wood and grass.
The 3D lightning mapping, determinations concerning cloud-to-ground or intracloud pulse and/or current characteristics calculations are preferably all performed by the central server (i.e. the detector records, timestamps, and submits the electric field waveshape to the central server for processing), though it is also within the scope of the disclosure that, for example to save on internet bandwidth in remote locations, or one or more of the steps/functions can be performed by the detection system (i.e. be included in the detection system/HRL detectors electronics, FPGA, circuitry and/or software) and be included when the detection system forwards the information it received regarding the lightning strike to the central server. Thus, preferably the detector records the electric field waveshape. timestamps it and sends it to the central database. However, this can be a lot of data, so in remote locations the FPGA can be programed to calculate lightning parameters (e.g. time of field peaks, electric field peak of return stroke) locally.
As illustrated in
The HF channel captures information about each electromagnetic pulse emitted by the lightning leader. The HF antenna preferably can have a short (1 ms, etc.) decay time constant, so the HF channel can also be called or considered the fast channel. For this reason, preferably all of the pulses in the HF channel can have a fast decay (i.e. they are short, well-defined pulses see in
The LF channel is not ideal for location information, because low frequencies are not ideal for measuring short pulses. Rather, it is better or preferred to measure slower lightning processes in the LF range. For this reason, the LF antenna is often also called or considered the slow antenna. Relatively slow processes (lasting 10 s to 100 s of ms) are best captured by the LF antenna, as the LF antenna has a long (1 second, etc.) decay time constant, which allows the system and method (including the AI/Machine Learning algorithm) to accurately detect long-continuing-current processes without having to compensate for instrumental decay.
In case the LF channel is not available, a novel deconvolutional method can be used to transform the HF signal and obtain electric field waveshapes that can resemble the LF signal. When the time constants are much smaller than the time variations in the signal under consideration, the output of the antenna system can follow the temporal behavior of electric field derivative, which can be referred to as the HF measurement. Usually, HF measurement systems have times constants smaller than a few milliseconds.
Thus, the actual electric field profile (LF) can be obtained from the data recorded by the acquisition system (HF). Such procedure can be defined as a deconvolution process.
The signal processing procedure shown in
Afterwards, the continuous-time dynamic system can be converted to a discrete-time system by means of a function available on MATLAB®. As an input it can use the sampling rate of the digitizer, which can be 6 MSps for all data measured by the HF system. Therefore, applying the c2d function of MATLAB®, the discrete-time transfer function and its discrete-time constants Cd
The Z-transform equation shown in (2) can be validated by means of a test, which can be performed by using the step function available in MATLAB®. It's expected that both the continuous-time and the discrete-time transfer functions reproduce the same result when a step function is applied, since they represent the same system. Once the transfer function has been evaluated, the system can be described by difference equations, as shown in (3).
The compensated electric field can be obtained by applying the expression (3) considering the measured Ua.
The disclosed system and method also provide for a novel process for triggering fire cameras, drones, other aircraft, tasked satellites and/or other spacecraft for confirming HRL lightning events and/or whether fire ignition has occurred at the determined spot of the lightning strike. The system and method trigger the drones and cameras based on detected lightning strikes, and preferably HRL detected lightning strikes. Real-time lightning data can be preferably used as triggers for one or more Pan-Tilt-Zoom (PTZ) cameras (though other cameras can be used and are considered within the scope of the disclosure) and/or drones and allows for the camera systems and drones to be efficiently triggered for superior performance over prior usage of cameras and drones for similar settings. The PTZ cameras and drones can be supplied with the latitude, longitude, and error ellipse for a given lightning stroke and the cameras and/or drones use the information to automatically pan, tilt, and zoom to monitor the area within the error ellipse. This enables high-resolution instant monitoring.
The disclosed novel system and method allows for drone efficiency to be maximized and drone operation costs to be minimized as the system/method allows the drones that are triggered to be sent to a specific location (latitude, longitude, error ellipse) to verify and/or extinguish a fire. The system and method can also ease regulatory concerns, as the drones can be programmed to only collect data at the specific lightning strike locations.
The system can comprise of two, non-limiting, main components:
Thus, preferably, as seen in
Satellite-based verification can also be used, preferably in addition to the cameras and/or drones, though, it is also within the scope of the disclosure to perform satellite-based verification without verifying with cameras and/or drones.
Lightning data can be incorporated into analysis performed by the AI/system and such data can be obtained through extracting useful information from satellite-based and earth-based observations. This satellite data can be used to validate the High-Risk-Lightning ignitions. Thus, one detection algorithm of the disclosed detection system and method can use satellite-based observations. As a baseline application, this algorithm can use high-resolution (preferably less than 500 m resolution), regular (preferably about or less than every 12 hours) infrared observations of the covered area. The algorithm can incorporate multiple infrared and optical bands along with weather or environmental information to further improve its sensitivity. The algorithm can than search for anomalous patterns in the satellite data that shows excess infrared radiation compared to what would be expected based on long-term trends and the radiation of the surrounding area. These anomalies can then be identified if they reach a predefined level of certainty. A machine learning-based method can be employed to optimize the algorithm and set its threshold to identify fires with high confidence when comparing the novel system's results to fires reported from other source, such as, but not limited to fires reported by CalFire in California over the year 2020, as well as other years and other fire reporting sources. The relevant steps of the algorithm are described and visually illustrated in
The fires identified by the algorithm were considered in the validation of the High-Risk-Lightning detection algorithm. Preferably, a lightning strike can be considered to be truly high-risk if it temporally and spatially coincided with a fire. For spatial coincidence, allowance can be made for a 2 km difference between the fire's identified location and the lightning strike's identified location given the uncertainties in both of these localizations. For temporal coincidence, allowance for 3 days of time difference between a lightning strike and the identified start of the fire can be made, requiring that the lightning struck prior to the identified start of the fire. This time difference can account for possible delays in identifying a fire after its ignition, and the possibility that the spread of a fire is delayed following ignition due to environmental factors (e.g. a lightning strike can ignite a tree, but the fire only spreads beyond the tree once the surrounding vegetation dries sufficiently).
As seen in
To evaluate the High-Risk-Lightning identification algorithm of the disclosed novel system, false alarm probability and false dismissal probability can be used. The false alarm probability is the probability that a High-Risk-Lightning alert created by the algorithm does not correspond to an actual High-Risk-Lightning event. The false dismissal probability is the probability that a real High-Risk-Lightning event is missed by the algorithm which does not generate any corresponding alert. To estimate the false alarm probability and false dismissal probability, a known list of correctly classified fires can be first considered. For this purpose, and as a non-limiting example/source, the officially reported fires in California listed in CalFire's database can be used and the first were checked in NASA's FIRMS. The following procedure was then carried out:
Therefore:
The above false dismissal and false alarm probabilities are preferably not fixed quantities. Rather, they can be tuned by changing parameters in the detection algorithm. In general, one can reduce the false alarm probability at the expense of higher false dismissal probability, and vice versa. This is useful as different applications may require different tuning, e.g. for some applications it may be more important to have low false alarm rate, while others may tolerate more false alarms (i.e. alerts that do not correspond to actual High-Risk-Lightning) but prefer less false dismissals (i.e. true High-Risk-lightning events that do not result in alerts by the algorithm-falsely determining that there is no fire, when there actually is a fire). To accommodate these possibilities, it was determined that the false dismissal probability of the detection algorithm as a function of the false alarm probability, or the so-called receiver operating characteristic (ROC) curve.
In addition to the ROC curve, the delay between ignition (by lightning) and the time of fire detection by the satellite algorithm can be measured. Both satellite and earth-based observations can detect a lightning strike and recover the time of strike with much higher precision (less than one second) than needed for the intended task of the disclosed system and method. The satellite based fire detection can identify the fire once it is sufficiently large given the resolution and sensitivity of the satellite (typically an extent of tens of meters) and when the satellite observes the area of the fire. These two requirements typically can introduce a delay between the start of the fire and its detection and varies between lightning strikes depending both on the environment in which the lightning struck, and the satellites' observing schedule. This delay can also be a function of the false alarm and false dismissal probabilities: setting the sensitivity of the detection algorithm higher can typically reduce the time delay and the false dismissal rate, but at the same time increase the false alarm rate.
To compute the above time delay, for each fire that was associated with a lightning the time difference between the lightning strike and the time of detection can be measured and the delay can be characterized as a function of the false alarm probability, which can help to understand whether allowing for higher false alarm rate achieved lower delays. When determining how the system's results compared to other methods, the obtained delays to the same delays found for CalFire's official reported times for fires associated with lightning strikes can be compared. The results showed that the detection algorithm of the disclosed system has successfully and significantly reduced the delay between ignition and detection for at least some of the co-detected wildfires.
Certain non-limiting benefits, advantages and/or characteristics provided by the novel system and method disclosed herein include:
Concentric antennas configuration 600 can preferably be flat-plate antennas and can allow a high-frequency (HF) antenna and a low-frequency (LF) antenna to be positioned concentric to each other. This configuration can allow for great space saving (when compared to other flat-plate antenna designs) and can also support portability of concentric antennas configuration 600. The LF disk can be the donut like, outer disk/plate 620, preferably having/defining central opening/hole 622, while the HF plate can be the inner disk/plate 610, or vice versa. Though not limiting, both antenna plates 610 and 620 can have the same surface area and antennas 610 and 620 can be designed to receive the specific range of the electromagnetic signal frequencies in lightning phenomena, in conjunction with the antenna circuitry located in the electronic box (See
Because of the preferred circular design of both the HF and LF antennas, the gain values can be accurately calibrated for superior measurement capabilities. The antenna gain values can be calibrated using a reference electromagnetic signal, by changing the values of the potentiometers in the printed circuit board to change the Resistor Capacitor variables in the circuit accordingly. The use of a potentiometer provides for flexibility in that it allows for adjustments to the gain values. However, the system can also be designed and/or configured such that a fixed resistor can be used in place of the potentiometer. Non-limiting examples where a fixed resistor may be used include, where the exact desired gain is known or for accommodation for local noise conditions.
When using a potentiometer, when calibrating in the lab as opposed to in the field of use, the reference signal can be simulated with a voltage generator and measured with an oscilloscope until the optimal gain values in the circuit are reached. The calibration process can take into account the shape of the antenna plates and its physical properties and the high amplitude and frequency content of these signals. Preferably, the antennas are calibrated for lightning electromagnetic signals using a “field calibration” technique, which can involve setting up the antennas in the field and measuring the signals they receive from a known source of electromagnetic radiation, such as a nearby lightning strike. The received signal can then be analyzed to determine the amplitude and frequency content, and the antennas can be adjusted to optimize their gain for that frequency range. Both of the above described techniques can be employed to obtain ideal gain values for all antennas. It is possible and within the scope of the disclosure to use other techniques such as simulation or modeling to calibrate an antenna. However, these techniques are less desired for calibrating a plate antenna designed to capture lightning electromagnetic signals due to the complex and dynamic nature of lightning strikes. Overall, minor, if any, calibrations are necessary after the initial gain adjustment values are set from the tested optimal gain.
Concentric antennas configuration 600 preferably also includes a shielding plate 650 with its circular lip/wall 654 and bottom surface 652. Shielding plate 650 can provide a reference ground to the electromagnetic signals and can protect the HF and LF antennas from any unwanted electromagnetic noise that would otherwise cause disturbance to the HF and LF measurements. This filtering of the 50 Hz/60 Hz noise allows for successful measurements to be obtained. Shielding plate 650 (i.e. ground plate) is preferably a conductive plate that is used as a reference ground for the antennas. It is typically placed beneath or around the antennas to provide a stable, low-impedance ground reference. Shielding plate 650 provides a stable reference ground for the antennas by acting as a conductive surface beneath or around the antennas (i.e. bottom surface 652 and lip/wall 654) in case there is extra unwanted charge or current present in the antennas as a whole. Shielding plate 650 also acts as a shield between the antennas and external sources of electromagnetic interference. When an external source of electromagnetic radiation, such as a nearby power line or electronic device, encounters shielding plate 650, plate 650 can effectively absorb or reflect the electromagnetic energy, preventing it from entering the antennas and affecting the signal quality. This helps to ensure that the antennas operate as intended and reduces the risk of unwanted noise or interference.
If the wires that connect to the two antennas were flipped, there is no alteration in the gain of the frequencies, but instead, in the capacitance. This change in capacitance is small enough compared to the Resistor Capacitor circuitry inside the electronic box that follows the antenna. However, there may be more noise in the plate 620 most likely because of this small difference in capacitance. Preferably, the system can use the High Frequency signal to locate the position of the lightning strike more heavily, and therefore this frequency preferably is acquired from inner plate 610 with less noise interference.
Shielding plate 650 can also act as the electronic grounding in case the antennas experiences unwanted current on the antenna plates. To provide separation between the HF antenna, LF antenna, and shielding plate, preferably an insulating member 630 can be provided and can be constructed from an acrylic or other insulating material. Insulating member 630 can be placed in between plates 610 and 620 and shielding plate 650 and is preferably sections through divider walls 632 and 634 and bottom surfaces 636 and 638. Inner plate is received within isolated area 639, while outer plate 620 is received within isolated area 637. The outer diameter of insulating member 630 preferably smaller than the inner receiving area 653 of shielding plate 650 such that insulating member 630, with plates 610 and 620 received within areas 639 and 637, respectively, is received within area 653 when concentric antennas configuration/assembly 600 is fully assembled (See
The entire shielding plate 650 can also be grounded by connecting it to pole 506 running into the ground 600. Preferably, pole 506 is a metal pole or constructed from another conductive material. As seen in
Preferably, plates/antennas 610 and 620 can be symmetric and the top and bottom surfaces are the same. For disposing plates within the receiving areas 637 and 637 of insulating member 630, the side of the plates that is electrically connected to the wiring preferable is the side of the plates that is visible when plates 610 and 620 are received by insulating member 630 (See
Insulating member 630 can be glued, held by VELCRO hook and loop fasteners, tapes or other adhesives to shielding plate 650 while plates 610 and 620 can be similarly connected to insulating member 630 using one of the above connection adhesives. Any type of conductive material is considered within the scope of the disclosure for use in constructing shielding plate 650 and plates 610 and 620. Preferably concentric antennas configuration/assembly 600 is fully enclosed and hidden within housing/dome of top member 510. Preferably, the housing/dome of top member 510 can be made from a non-conductive material so that it doesn't block the signals from getting to antennas 610 and 620 located within top member 510. Were the top member housing/dome conductive it would act as the shielding plate all around the antennas, such that no electromagnetic signal would penetrate internally.
Antenna plates 610 and 620 and shielding plate 650 can be preferably connected to the electronics via ring terminals (See
The electronics box preferably houses the system electronics/circuitry. The lid 693 of the electronics box (
A non-limiting embodiment for the assembled system 500 is shown in
As seen in
Additionally, though the novel concentric antenna configuration/assembly 600 is described above as being used with detection system 500 shown in
As noted above, the above described systems can also be used for detecting/determining High-Risk-Lightning and/or other lightning strikes directly on or affecting powerlines, power generation systems and/or other objects in addition to lightning strikes igniting wildfires. With respect to powerlines, when a powerline is struck or otherwise affected by a lightning strike such as a High-Risk-Lightning strike, it can result in severe damage due to the extreme electrical and thermal effects produced. The specific mechanisms of damage can include, without limitation:
1. Ohmic Heating: The lightning strike/High-Risk-Lightning strike can generate an intense current flow through the powerline conductors. The high current encounters resistance in the conductors, which can lead to the generation of heat according to Ohm's law (Heat=Current{circumflex over ( )}2×Resistance). The excessive heat can cause the conductors to reach temperatures that exceed their melting point or cause localized vaporization of the metal, resulting in a complete or partial break in the powerline.
2. Electromagnetic Forces: The high electrical current flowing through the powerline during a lightning strike/High-Risk-Lightning strike can create a strong magnetic field around the conductors. This magnetic field induces Lorentz forces which can cause mechanical stress and can result in the bending, stretching, or even fracture of the powerline conductors.
3. Arcing and Explosions: A lightning strike/High-Risk-Lightning strike can create an arc of electricity between the powerline conductors or between the conductors and nearby objects such as trees or buildings. The often intense current flow during the arc can cause localized explosions, leading to physical damage to the powerline components. Melting or burning of the conductors, insulators, and other equipment can occur due to the high temperatures generated by the arc.
4. Voltage Surges: Lightning strikes/High-Risk-Lightning strikes can generate powerful electromagnetic fields that can induce voltage surges in nearby powerlines. These induced surges can exceed the normal operating voltage levels, overwhelming the protective devices in the powerline system. The sudden increase in voltage can cause insulation breakdown, damage transformers, switches, and other electrical equipment connected to the powerline.
5. Corona Discharge: During a lightning strike/High-Risk-Lightning strike, the often intense electric field surrounding the powerline can ionize the surrounding air, resulting in a phenomenon known as corona discharge. Corona discharge can lead to power loss, increased electrical noise, and damage to insulators. It can affect the overall efficiency and reliability of the powerline system.
6. Grounding System Damage: Lightning strikes may also impact the grounding systems of powerlines. Grounding plays a crucial role in providing a safe path for lightning discharges, but a High-Risk-Lightning strike can overwhelm the grounding system, leading to flashovers and damage to the grounding conductors, electrodes, or grounding connections.
As noted above, when monitoring for lightning strikes, such as HRL strikes affecting powerlines and/or power generation systems, the same detector setup as described above for detecting lightning strikes that can ignite a forest fire/wildfire can be used for the powerline application as well. One noted difference or consideration between the two determinations is that with the powerline monitoring/determinations any underlying vegetation, weather, and environmental parameters is typically not needed or used. For powerline applications the detailed characteristics of the powerlines (including voltage rating, insulation level, tower geometry, and type of grounding system) can be used to determine the probability of damage from a given lightning strike. Preferably in the powerline application, the detailed lightning strike classification (electric field profile, current duration, charge transfer) can be used by the system to determine the risk to powerlines associated with each strike.
For the powerline application, the detectors for the system can be placed in a similar grid fashion as for the forest application, in order to allow for better location accuracy measurements (as a non-limiting example triangulation with the time-of-arrival technique).
When distinguishing between a HRL strike that actually hits/impacts the powerline or other physical object from a HRL strike that was close by but didn't actually harm the powerline the “attractive area” approach can be used (See
With power outages, response speed and efficiency can be critical. Every minute that the power is out on a major grid, significant income to the utility company is lost and the broader economic impacts are even greater. When a customer calls about a power outage the affected utility company has to mobilize resources to assess often tens of miles of powerlines to find the problem area. Then, the utility company must assess the exact type of damage and develop a power restoration strategy. This current approach consumes time and resources. With the HRL location provided by the above-described systems, the utility company can know exactly where to go and based on the HRL risk profile the utility company can also know what type of damages to expect. This reduces response, inspection, and power restoration times.
Utility companies are constantly challenged with reducing the wildfire risk near their infrastructure, both from the community and also from a regulatory perspective. It is also important to the utility company to protect their own infrastructure from potential unnoticed wildfire events, while they want to make sure that a fire caused by their assets does not get confused with a lightning-caused fire from a liability perspective. The utility company would also like to minimize the overall risk of wildfire near their service areas to avoid Public Safety Power Shutoffs (PSPS). Using the “attractive area” for powerlines, the taller the powerline pole, the bigger the attractive radius becomes around the powerline (it is also a function of the type of material the powerline is made out of—as denoted by the letters in the below Graph). If a lightning ellipse falls within this attractive radius, then the powerline can attract the lightning strike to its surface.
For powerline and power generation applications the detailed characteristics of the powerlines or power generation system (which can include voltage rating, insulation level, tower or installation geometry, and type of grounding system) can be used to determine the probability of damage to the powerlines or power generation system from a given lightning strike. As visually illustrated in
All measurements, dimensions, shapes, amounts, angles, values, percentages, materials, degrees, configurations, orientations, component layouts and configurations, mechanical/electrical supports, mechanical/electrical connection and connection mechanisms, mechanical/electrical movement or control mechanisms, communication technologies, data sources, product layout, components or parts; component or part locations, sizes, number of sections, number of components or parts, etc. discussed above or shown in the Figures are merely by way of example and are not considered limiting and other measurements, dimensions, shapes, amounts, angles, values, percentages, materials, degrees, configurations, orientations, component layouts and configurations, mechanical/electrical supports, mechanical/electrical connection and connection mechanisms, mechanical/electrical movement or control mechanisms, communication technologies, data sources, product layout, components or parts; component or part locations, sizes, number of sections, number of components or parts, etc. can be chosen and used and all are considered within the scope of the disclosure.
It will be seen that the objects set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the disclosure, it is intended that all matters contained in the foregoing description shall be interpreted as illustrative and not in a limiting sense. The HRL lightning detection system has been shown and described herein in what is considered to be the most practical and preferred embodiment.
It should be understood that the exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from their spirit and scope.
Unless feature(s), part(s), component(s), characteristic(s) or function(s) described in the specification or shown in the drawings for a claim element, claim step or claim term specifically appear in the claim with the claim element, claim step or claim term, then the inventor does not consider such feature(s), part(s), component(s), characteristic(s) or function(s) to be included for the claim element, claim step or claim term in the claim when and if the claim element, claim step or claim term is examined, interpreted or construed. Similarly, with respect to any “means for” elements in the claims, the inventor considers such language to require only the minimal amount of features, components, steps, or parts from the specification to achieve the function of the “means for” language and not all of the features, components, steps or parts describe in the specification that are related to the function of the “means for” language.
Dimensions and/or proportions of certain parts in the figures may have been modified and/or exaggerated for the purpose of clarity of illustration and are not considered limiting.
While the HRL lightning detection system and method of use have been described and disclosed in certain terms and has disclosed certain embodiments or modifications, persons skilled in the art who have acquainted themselves with the disclosure, will appreciate that it is not necessarily limited by such terms, nor to the specific embodiments and modifications disclosed herein. Thus, a wide variety of alternatives, suggested by the teachings herein, can be practiced without departing from the spirit of the disclosure, and rights to such alternatives are particularly reserved and considered within the scope of the disclosure.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the disclosure. Accordingly, it is to be understood that the novel HRL lightning detection system and method of use have been described by way of illustrations and not limitation. This description and the accompanying drawings illustrate exemplary embodiments for the system and method. Other embodiments are possible and modifications may be made to the exemplary embodiments without departing from the spirit and scope of the disclosure. It will be apparent to one of ordinary skill in the art that the embodiments as described above may be implemented in many different embodiments of electronics, computer chips, software, circuitry, antennas, sensors, third party data source etc. Therefore, the description and drawings are not meant to limit the disclosure. Instead, the appended claims define the scope of the disclosure.
This application is a continuation-in-part of U.S. application Ser. No. 17/857,155, filed Jul. 4, 2022, which claims the benefit of and priority to U.S. Application Ser. No. 63/263,886, filed Nov. 11, 2021, U.S. Application Ser. No. 63/203,238, filed Jul. 14, 2021, and U.S. Application Ser. No. 63/218,423, filed Jul. 5, 2021, all of the above-identified applications and any accompanying documentations filed along with one or more of the applications are incorporated by reference in their entireties as if fully set forth herein and for all purposes.
Number | Date | Country | |
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63263886 | Nov 2021 | US | |
63203238 | Jul 2021 | US | |
63218423 | Jul 2021 | US |
Number | Date | Country | |
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Parent | 17857155 | Jul 2022 | US |
Child | 18369052 | US |