Lightning Position Research Articles

Error Analysis of Non-Time-Synchronized Lightning Positioning Method

Since the non-time-synchronized lightning positioning method does not rely on the time synchronization of the stations in the positioning system, it eliminates the errors arising from the pursuit of time synchronization and potentially achieves higher positioning accuracy. This paper provides a comprehensive overview of the errors present in the three-dimensional lightning positioning system. It compares the results of traditional positioning methods with those of non-time-synchronized lightning positioning algorithms. Subsequently, a simulation analysis of the positioning errors is conducted specifically for the non-time-synchronized lightning positioning method. The results show that (1) the non-time-synchronized lightning positioning method exhibits greater errors when utilizing two randomly positioned radiation sources for location determination. Consequently, the resulting positioning outcomes only provide a general overview of the lightning discharge. (2) The positioning outcomes resemble those of the traditional method when employing a fixed-coordinate beacon point. However, the errors in the three-dimensional positional coordinates of these fixed-coordinate beacon points significantly impact the deviations in the positioning results. This impact is positively correlated with the positional error of the beacon point, considering both the orientation and magnitude. (3) Similarly to the traditional method, the farther away from the center of the positioning network, the larger the radial error. (4) The spatial position of the selected fixed-coordinate beacon point has little influence on the error.

Architecture Research on Differentiated Lightning Protection of Distribution Network Considering Plateau Microtopography

Abstract Lightning is the main and severe threat to 10kV and 35kV medium-voltage distribution networks. It will cause equipment failures or damage, tripping and even power outages. With the construction of modern distribution networks, the requirements for power supply reliability are getting higher and higher. Therefore, lightning protection of distribution networks has received great attention. The key point is to find a cost-effective way to protect against lightning. This paper proposed an architecture for differentiated lightning protection of distribution networks considering plateau micro-topography. The main idea is to take multiple measures to obtain rich data, including a lightning positioning system, 3D laser scanning and digital elevation model. Differences in lightning parameters, line and tower parameters, topographic parameters are thought to bring different lightning tripping rates for each tower. Then tripping rate of each area element is obtained through meshing and discrete calculation. Total tripping rate is finally obtained by summation of all elements. The proposed architecture plans to provide a clue for differentiated lightning protection for the distribution network.

Refined risk assessment and differentiated protection of lightning damage in distribution network lines considering the underlying surface environment

The distribution line is widely distributed and the span of pole-towers is small. However, the existing lightning positioning system has limited positioning accuracy, and the lightning strike coordinates it locates have certain deviations for the distribution network. The lightning hazard risk divided by lightning density is not sufficient to support the differentiated lightning protection transformation of the distribution network. The environment of the underlying surface where the pole-tower is located has a significant impact on lightning activity, so this paper combines terrain, climate, lightning current characteristics, and historical lightning trip data to finely evaluate the lightning risk level in the distribution line pole-tower area. This paper provides a detailed analysis of the relationship between different underlying surface environments and lightning current characteristics and utilizes the entropy weight method to construct a comprehensive lightning disaster risk index, then evaluates the risk level of lightning disaster in different regions, and corrects it through lightning fault data. Overlaying the risk level of the area and the distribution map of the pole-tower foundation coordinates, it will obtain the distribution of lightning hazard-pregnant risk at the pole-tower area, which would contribute to guiding the differentiated lightning protection transformation of the line. Compared to traditional unified lightning protection renovation methods, differentiated lightning protection methods that integrate factors such as pole-tower structure, wire type, and lightning risk level can achieve significant lightning protection effects at a lower economic cost. Taking Nanchang City as an example, risk assessment and lightning protection renovation were conducted on 21 distribution lines. The average number of lightning trips per year is 55 before the renovation, but it is only 4 after the renovation, which the number of lightning trips significantly reduce. This verifies the effectiveness of using lightning hazard-pregnant assessment results to guide differentiated lightning protection methods.

VLF/LF High Precision 3D Lightning Positioning System Establishment and Application

VLF/LF High Precision 3D Lightning Positioning System Establishment and Application

Evaluation of lightning warning technique with multi-source data for Vung Tau coastal area

In this paper, the authors used multi-source data, including the electric field data observed by EFM-100C at Rescue Station No. 1 on the “Bai Sau” beach in Vung Tau coastal area for 166 days from May to October 2019; Himawari satellite data and Nha Be weather radar data and the GLD-360 lightning position data to evaluate the lightning warning method. Radar and satellite data were used to determine deep convective clouds. The GLD-360 lightning position data were used to examine the consistency of lightning location with the deep convective clouds. The “two areas” method was applied. The Area of Concern (AOC) has a radius of 10 km from the electric field measurement station. The Warning Area (WA) is 20 km extending from the outermost AOC area. Due to the influence of sea-salt aerosol on the background electric field intensity, the electric field threshold selected for a warning is larger than the absolute value (1.5 kV/m). The results showed that the probability of detection (POD), failure to warn (FTW), and false alarm ratio (FAR) were 86.3%, 13.07%, and 23.17%, respectively. The average time of lightning warning for the Vung Tau coastal area is 23 minutes in advance. The warning time is equivalent to that in some studies around the world. The value is suitable for practical application in lightning prevention on the beach and in the Vung Tau coastal area.

Three-Dimensional Lightning Positioning in Low-Frequency Band Using Time Reversal in Frequency Domain

A low-frequency lightning location system was established and operated. The time-reversal approach in the frequency domain (TRFD) is applied to the system for three-dimensional (3-D) lightning source location finding. The TRFD method uses back propagation of the signals detected at each site and determines the source location automatically using the focusing point of the back-propagated waves. Three cases are reported to showcase the capability of the method. The first case is the 3-D localization of an intra-cloud flash over the network. Both TRFD and time-of-arrival (TOA) method provide LF lightning sources that are in consistent with very high frequency (VHF) sources. The lightning sources located by TRFD method reveal more details and are more continuous compared to those obtained by TOA method used in this paper. The second case concerns the localization of an artificially triggered lightning flash with a horizontal error of 30 m by TRFD. The third case is a multi-stroke cloud-to-ground flash that shows location differences between four return strokes (RSs) being less than 60 m. Furthermore, a special case was used to demonstrate the ability of the proposed method in locating RS grounding points by combining two successive RSs when the TOA is not available.

FDTD Analysis of Nearby Lightning Surges Flowing Into a Distribution Line via Groundings

This paper investigates lightning surges on a distribution line reported using a finite-difference time-domain (FDTD) method. FDTD simulation results show a satisfactory agreement with measured lightning currents when lightning strikes ground nearby a distribution line. The current and voltage characteristics along the line, which were not measured in the test, are calculated by the FDTD simulation. Parametric analysis shows that lightning currents and voltages are dependent on the lightning position, distance from the lightning to the nearest pole, and pole grounding resistance. A large portion of phase-wire voltage is induced by the lightning channel current, and correspondingly, a large portion of phase-wire current is produced by the induced voltage. When the lightning channel is inclined, the peak current and voltage vary by +10% to -10% depending on the inclined angle. The effect of neutral wire position in the line is also investigated, and the induced voltage at the nearest pole to the lightning can be effectively suppressed by installing two neutral wires above and under the phase wires. EMTP simulation results agree qualitatively well with the measurement and FDTD results.

Analysis about Influence on Surrounding Lightning Environment of Communication Base Station Based on One Lightning Disaster

With the lightning position data in recent years of Jiangsu, satellite and live data on 3rd,July,2012, the reasons for the damage to office room equipment beside a communication base station in Wujin District, Changzhou were analyzed, and reasonable suggestions were given. Based on the lightning accident, this paper analyzed the reasons of lightning strike to buildings near communication base station from weather, lightning strike probability, the validity of lightning protection device and potential. It is mainly because of lightning electromagnetic pulse. Base station can protect the buildings inside the protective area from direct strike, but which increased the possibility of damage to equipment from lightning impulse, at the same time, direct lightning strike probability in the scattered strike zone may increase. Therefore communication base station should be sufficiently far away from the building, when it cant meet a safe distance, not only the direct lightning protection measures should be taken to protect the station and buildings, but also protection measures against lightning electromagnetic pulse for equipment in buildings around are needed.

Lightning-produced NO x budget over the Highveld region of South Africa

Measurements of lightning events recorded by a lightning position and tracking system (LPATS) were used to estimate the contribution of lightning to the nitrogen oxide (NO x ) burden over the Highveld region (taken as the 4° area, Lat. 25–29°, Lon. 27–31°) of South Africa. Lightning data collected in the year 2002, comprising a total of 2 417 074 cloud-to-ground (CG) strokes, were analyzed. Lightning strokes were grouped into flashes by considering strokes occurring within radii of 10 km and time intervals of 1 s apart as belonging to the same lightning flash. Making use of a production rate of 10×10 16 molecules of NO J −1 and an energy dissipation of 6.7×10 9 J flash −1, an emission factor of 51.2 kg NO 2 flash −1 was derived. This emission factor was employed to calculate the lightning-produced NO x (LNO x ) budget of 65 (2.8–200) kt NO 2 yr −1 over the Highveld region. Our calculated LNO x is about 9% of reported NO x emissions from coal-fired power plants over the Highveld during 2002. An annual contour plot of LNO x showed that the distribution of NO x production over the Highveld is highly non-uniform, with high concentrations of LNO x over the central Highveld. These results indicate that in evaluating NO x and tropospheric ozone chemistry over the South African Highveld both natural lightning and industrial sources of NO x need to be taken into account.

Comparison of a SAFIR lightning detection network in northern Germany to the operational BLIDS network

This paper presents a comparison of a regional lightning detection network based on SAFIR sensors (Surveillance et Alerte Foudre par Interférometrie Radioélectrique) with the operational German lightning detection system (BLIDS) that uses LPATS (Lightning Positioning and Tracking System) and IMPACT (Improved Performance from Combined Technology) sensors. The Institute for Meteorology and Climatology (IMUK) of the University of Hannover runs a regional lightning detection network in northern Germany (UHSN). It consists of three SAFIR receiving stations in a triangle of about 180 km side‐length. As an a priori assumption that either BLIDS or UHSN represents the truth is not possible, the relative performance of each system in comparison with the other one is investigated. Probability of detection (POD) is used to investigate flash events simultaneously sensed by both networks. POD of UHSN was calculated assuming BLIDS measurements as true and, vice versa, POD of BLIDS was calculated assuming UHSN measurements as true. This comparison yielded that UHSN, as expected, is far more sensitive to intracloud lightning. In contrast, the sensitivity of UHSN for cloud‐to‐ground lightning was much lower than that of the BLIDS network. Hence the sensitivity of UHSN for both lightning types together (total lightning) is dominated by intracloud lightning and is consequently higher than that for BLIDS. The sensitivity of UHSN was found to exhibit strong horizontal variations. These are dominated by the network geometry and data processing procedures. The present study shows strengths and weaknesses of both systems and contributes to a better assessment of the potentials of each system.

Lightning Activity over Land and Sea on the Eastern Coast of the Mediterranean

This paper presents a study of the characteristics of lightning activity during the Cyprus low winter storms over the eastern coast of the Mediterranean. The focus is on changes in the nature of thunderstorms crossing the coastline from the sea into the northern and central parts of Israel, as manifested in their electrical activity. It is based on the Lightning Position and Tracking System (LPATS) measurements of lightning ground strikes during four winter seasons between 1995 and 1999. The spatial distribution shows a maximum of lightning ground strikes over Mount Carmel, possibly due to its topographical forcing. The annual variation shows a major maximum in January with two minor peaks, one in November and another in March, which can be explained by changes in the static instability of the atmosphere throughout the rainy period. The average fraction of positive ground flashes was found to be 6% and their average peak current +41 kA. The average peak current of negative ground flashes was −27 kA. Larger frequencies of ground flashes were detected over the sea than over land during the study period. This is probably due to the large heat and humidity fluxes from the sea surface, which destabilize the colder air above and drive cloud convection. The annual distribution shows that during midwinter (December–January–February) there is higher flash density over the sea, while during autumn and spring the flash density is similar above the two regions. The diurnal variation shows that the maximum in maritime lightning activity was at 0500 LST and over land at 1300 LST. The mean peak current of positive ground flashes was higher over land and of negative ground flashes, over the sea.

A seven-year study about the negative cloud-to-ground lightning flash characteristics in Southeastern Brazil

A seven-year study of negative cloud-to-ground (CG) lightning flash characteristics in southeastern Brazil is presented. The study is based on approximately 10 million flashes recorded by a Lightning Position and tracking system lightning detection network from November 1988 to December 1995. The data set is the longest ever obtained in the tropics using an almost constant network configuration. It provides a unique opportunity to study the long-term annual, monthly, and local time distributions of the number, intensity (peak current) and multiplicity of negative CG flashes in the tropics. The annual distribution of the number of flashes has variations as large as 80%. The variations does not show any clear relationship with any meteorological parameter, possibly indicating the complex interactions of different processes responsible for the lightning activity. The monthly and local time distributions seem to follow closely the related distributions of air temperature. The annual distribution of peak current shows an average value of 40.4 kA and has a significant decrease from 1991 to 1994, apparently related to an El Niño seasonal effect. The monthly distribution of peak current shows lower values in the winter, in contrast with the results recently reported for the United States, and seems to be related to the monthly distribution of the number of flashes. The local time distribution of the peak current seems also to be related to the local time distribution of the number of flashes; however, the dependency is less evident. The annual distribution of multiplicity has a systematic decrease during the period, with no apparent relationship with any of the variables studied. The monthly distribution of multiplicity is consistent with the hypothesis that the multiplicity is related to the average height of thunderstorms. The local time distribution of multiplicity, in turn, shows a sunrise/sunset effect. The results are compared to similar ones obtained in other regions of the world.

Advanced Lightning Location Correction of LPATS-T by Geographical Parameters

Tokyo Electric Power Company (TEPCO) introduced the Lightning Position and Tracking System (LPATS) Version III in 1990. The system uses the time-of-arrival technique for lightning location. TEPCO had studied the operating characteristics of the system, and had confirmed its effectiveness. However, further improvement of the functions and performance was necessary from the viewpoint of utilities. TEPCO, therefore, began development of the LPATS-T in cooperation with the Global Atmospherics, Inc. and formally put the system into operation in 1996.Performance of LPATS-T at TEPCO was evaluated based on comparison with actual lightning current measurement data at transmission towers. Sixty-one lightning locations at transmission towers were detected by LPATS-T from 1996 to 2000. Location error was estimated to be about 650 m on average. TEPCO corrected the lightning locations by the geographical propaga-tion path. As a result, location error was effectively improved when the lightning wavelength was set at 2, 000 m. The precision of lightning location by LPATS-T reduced the average error from 650 m to 330 m. Also, the standard deviation was 180 m from 390 m.

Winter Thunderstorms in Israel: A Study with Lightning Location Systems and Weather Radar

Abstract A study of the morphology and evolution of winter thunderstorms in Israel and over the eastern Mediterranean was conducted during the 1995–96 winter season. Electrically active cells were analyzed by combining data from weather radar and an operational lightning positioning and tracking system. This enabled the identification of reflectivity features of electrically active cells, and tracing of the spatial and temporal evolution of thunderstorms. The results show that, in winter, rain clouds became thunderclouds if their echo top was higher than 6500 m (at a temperature level colder than −30°C), provided that the reflectivity at the level of the −10°C isotherm was larger than 35 dBZ. The period between the first radar echo and the first detected lightning flash (probably a ground flash) was found to be 10–15 min, a period at which the top of the 40-dBZ echo was located higher than the −8°C level.

Evaluation of LPATS data using VHF interferometric observations of lightning flashes during the Eulinox experiment

During the Eulinox (European Lightning Nitrogen Oxides Project) campaign, two lightning sensors were available: a Lightning Position and Tracking System (LPATS), and the ONERA VHF interferometric (ITF) mapper. We looked for the typical VHF signature of positive and negative cloud-to-ground flashes in ITF records in order to separate intra-cloud (IC) flashes from cloud-to-ground (CG) flashes during five periods from 2 days. Then we used this set of data to check the efficiency of the South Germany LPATS. We concluded that this LPATS detected nearly all the negative CG flashes, but one-fourth of LPATS negative strokes are in fact IC flashes. The ratio of misinterpretation is much smaller (15%) for multi-stroke negative CG flashes. The LPATS recorded 62% of the positive strokes, but only 43% with the right polarity, and only 25% of LPATS positive strokes actually belonged to a positive CG flash. This reliability ratio is 100% if we consider only high-intensity LPATS strokes.

Cloud‐to‐ground lightning in southeastern Brazil in 1993: 2. Time variations and flash characteristics

About 1.1 million cloud‐to‐ground lightning flashes were recorded by a lightning positioning and tracking system in southeastern Brazil in 1993. The data have been analyzed in terms of their monthly, seasonal (summer/winter), and diurnal (local time) variations. The monthly variation shows a double peak characteristic of tropical lightning activity. The seasonal variation indicates that most flashes occur in the spring and summer seasons, with less than 25% occurring in the autumn and winter. The lightning flash polarity and multiplicity were found to be very similar in the summer and winter seasons. Radiation field and direct current lightning data were obtained in towers located in the same region of the network to verify the multiplicity data obtained by the network. The results indicate that the multiplicity obtained by the system is much lower than that obtained by radiation field measurements of close lightning in the same region of Brazil. The lightning flash peak current were found to be larger in the summer than in the winter, in contrast with results obtained in other parts of the world. The diurnal variation of the negative flashes shows in the summer and winter seasons the same behavior, with a peak around 1500–1800 LT, associated with the maximum convective activity in the afternoon. The diurnal variation of positive flashes, in turn, shows this behavior only in the winter. In the summer, it shows a maximum around 1400–1500 LT, with a secondary peak at 1900 LT. However, considering only positive flashes with peak currents higher than 15 kA, the diurnal distribution in the summer is similar to that for negative flashes. This fact indicates that the positive flashes with a peak current less than 15 kA are probably intracloud flashes erroneously identified by the network. The results are discussed in association with the findings presented in paper 1 [Pinto et al., this issue] and compared with results obtained in other parts of the world.

Cloud‐to‐ground lightning in southeastern Brazil in 1993: 1. Geographical distribution

About 1.1 million cloud‐to‐ground lightning flashes were recorded by a lightning positioning and tracking system in southeastern Brazil in 1993. The 1‐year continuous lightning data set is the first obtained in Brazil. It has been analyzed for geographical distribution of total flash density, percentage of positive flashes, negative and positive flash densities, and negative and positive flash peak currents. The dependence of the flash density and peak current on latitude, altitude, and soil resistivity was investigated. Negative flash peak current was found to be inversely correlated with latitude, but no other significant correlation was found for flash density and peak current with these parameters. Positive flashes were found to be contaminated by intracloud flashes. The maximum total, negative, and positive flash densities were 15.5, 9.1, and 7.7 flashes/km2 per year, respectively. The average percentage of positive flashes was 36.5%. The geometric means of negative and positive peak current were 30.9 kA and 17.8 kA. The high density, high percentage and low average peak current of positive flashes found in this study are probably a result of such a contamination. Neglecting positive flashes below 15 kA, assuming that they correspond to intracloud flashes erroneously identified by the system, the maximum positive and total flash densities would be 3.9 flashes/km2 per year and 11.7 flashes/km2 per year. The percentage and geometric mean peak current of positive flash would be 23% and 38.7 kA, respectively. The results are discussed in the context of other similar measurements made at different parts of the world.

Motion characteristics of thunderstorms in southern Germany

AbstractThe motion of thunderstorms in southern Germany was investigated. The thunderstorms were observed by a lightning position system during the summer months of the years 1992–1996. On average every second day thunderstorms were observed somewhere in southern Germany. In general thunderstorms approached from westerly and south‐westerly directions. The average speed was 13 m s−1. No significant relation between the occurrence of thunderstorms and the large‐scale synoptic pattern described by the Grosswetterlagen (large‐scale weather pattern) was found. Thunderstorms were observed during almost all Grosswetterlagen. The reduction to eight weather patterns based on the low‐level flow in southern Germany showed that thunderstorms are likely when the flow has a westerly (43%) or easterly direction (20%). Three distinct groups of different lighting patterns could be identified: stationary, moving thunderstorms and thunderstorm lines. The convective available potential energy (CAPE) and the wind shear were retrieved from radio soundings from München and Stuttgart. On average CAPE was 583 J kg−1 for stationary thunderstorms, 701 J kg−1 for moving thunderstorms and 876 J kg−1 for thunderstorm lines. The corresponding average bulk Richardson numbers were 37, 22 and 21. The steering level was found to be at about 6 km m.s.l. However, it should be noted that in most cases the soundings do not completely describe the local environment of thunderstorms, since radio soundings are only available twice a day. Copyright © 1999 Royal Meteorological Society

Cloud‐to‐ground lightning flash characteristics in southeastern Brazil for the 1992–1993 summer season

A lightning positioning and tracking system (LPATS) has been used for the first time to obtain the cloud‐to‐ground flash characteristics in southeastern Brazil during the 1992–1993 summer season. About 300,000 flashes to ground were recorded. The lightning data are presented in terms of polarity, multiplicity, first‐stroke peak current, stroke of maximum peak current, and local time occurrence. The preliminary results are compared with lightning data obtained by several authors in other parts of the world.

A Comparative Analysis of the Temporal Variability of Lightning Observations and GOES Imagery

Lightning Positioning and Tracking System (LPATS) data received by the Cooperative Institute for Research in the Atmosphere via a real-time weather data network were used to study the temporal variability of lightning for a frontal system and hurricane that affected the United States in 1989. Our comparison of these data with GOES-7 imagery revealed that lightning data can help define the development, linearity, and maximum intensity of a frontal band as seen with the correlation of currents discharged by lightning to ground with associated IR temperature fields. Lightning data also revealed a dramatic increase in convection equatorward of Hurricane Chantal's vortex upon her rapid intensification and landfall, and the heavy rainfall amounts associated with the tropical storm correlated to areas of rather frequent lightning activity west of Galveston, Texas, on 1 August 1989.