Дисертації з теми "Lighting characteristics"
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1
Fernandes, Luis Lomelino. "From lighting performance goals to the optical characteristics of fenestration." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3207697.
Повний текст джерела
2
Anderson, David Ewart. "An investigation into the thermal performance of high temperature theatre luminaires, and the development of a mathematical model to predict and improve critical thermal operating characteristics." Thesis, Edinburgh Napier University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365202.
Повний текст джерела
3
Gonzalez-Velez, Enrique. "Safety Evaluation of Roadway Lighting Illuminance Levels and its Relationship with Nighttime Crash Injury Severity for West Central Florida Region." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3122.
Повний текст джерелаАнотація:
The main role of roadway lighting is to produce quick, accurate and comfortable visibility during nighttime conditions. It is commonly known that good lighting levels enable motorists, pedestrians and bicyclists to obtain necessary visual information in an effective and efficient manner. Many previous studies also proved that roadway lighting minimizes the likelihood of crashes by providing better visibility for roadway users.
Appropriate and adequate roadway lighting illuminance levels for each roadway classification and pedestrian areas are essential to provide safe and comfortable usage. These levels are usually provided by national, or local standards and guidelines. The Florida Department of Transportation (FDOT) Plan Preparation Manual recommends a roadway lighting illuminance level average standard of 1.0 horizontal foot candle (fc) for all the roadway segments used in this research. The FDOT Plan Preparation Manual also states that this value should be considered standard, but should be increased if necessary to maintain an acceptable uniformity illuminance ratio.
This study aimed to find the relationship between nighttime crash injury severity and roadway lighting illuminance. To accomplish this, the research team analyzed crash data and roadway lighting illuminance measured in roadway segments within the West Central Florida Region. An Ordered Probit Model was developed to understand the relationship between roadway lighting illuminance levels and crash injury severity. Additionally, a Negative Binomial Model was used to determine which roadway lighting illuminance levels can be more beneficial in reducing the counts of crashes resulting in injuries.
A comprehensive literature review was conducted using longitudinal studies with and without roadway lighting. Results showed that on the same roadways there was a significant decrease in the number of nighttime crashes with the presence of roadway lighting. In this research, roadway lighting illuminance was measured every 40 feet using an Advanced Lighting Measurement System (ALMS) on a total of 245 centerline miles of roadway segments within the West Central Florida Region. The data were mapped and then analyzed using the existing mile post.
During the process of crash data analysis, it was observed that rear-end collisions were the most common first harmful event observed in all crashes, regardless of the lighting conditions. Meanwhile, the average injury severity for all crashes, was found to be possible injury regardless of the lighting conditions (day, dark, dusk, and dawn).
Finally, this research presented an Ordered Probit Model, developed to understand the existing relationship between roadway lighting illuminance levels and injury severity within the West Central Florida Region. It was observed that having a roadway lighting average moving illuminance range between 0.4 to 0.6 foot candles (fc) was more likely to have a positive effect in reducing the probability of injury severity during a nighttime crash. A Negative Binomial Model was conducted to determine if the roadway lighting average moving illuminance level, found on the Ordered Probit Model was beneficial in reducing crash injury severity during nighttime, would also be beneficial in reducing the counts of crashes resulting in injuries. It was observed that a roadway lighting average moving illuminance, range between 0.4 to 0.6 fc, was more likely to reduce the count of crashes resulting in injuries during nighttime conditions, thus increasing roadway safety. It was also observed that other factors such as pavement condition, site location (intersection or no intersection), number of lanes, and traffic volume can affect the severity and counts of nighttime crashes.
The results of this study suggest that simply adding more roadway lighting does not make the roadway safer. The fact is that a reduction in the amount of roadway lighting illuminance can produce savings in energy consumption and help the environment by reducing light pollution. Moreover, these results show that designing roadway lighting systems go beyond the initial design process, it also requires continuous maintenance. Furthermore, regulations for new developments and the introduction of additional lighting sources near roadway facilities (that are not created with the intent of being used for roadway users) need to be created.
4
Engholm, Cynthia Dorothy Kidder. "Positive lightning and bipolar lightning patterns : observational characteristics." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/52900.
Повний текст джерелаАнотація:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989.Includes bibliographical references (leaves 211-214).
by Cynthia Dorothy Kidder Engholm.
M.S.
5
Драч, Юрій Олександрович. "Підвищення точності вимірювання геометричних розмірів мікрометричного діапазону шляхом вдосконалення вузла освітлення оптико-електронної системи". Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/38419.
Повний текст джерелаАнотація:
В даній магістерській дисертаційній роботі проведено аналітичне
дослідження будови оптико-електронної вимірювальної системи, її складових
вузлів та особливостей налаштування. З самої теми дисертації «Підвищення
точності вимірювання геометричних розмірів мікрометричного діапазону
шляхом вдосконалення вузла освітлення оптико-електронної системи» видно,
що шляхом підвищення точності вимірювання геометричних розмірів у
мікрометричному діапазону є вдосконалення джерела освітлення.
Ми визначили основні відомі методи визначення світло-технічних
характеристик джерел освітлення у другому розділі дисертації. В розділі нами
проаналізовано методи «інтегруючої сфери» та «гоніофотометричний» для
визначення світлового потоку освітлювальних систем з різним типом
світлового розподілу. Звісно, ми розглядали методи світового досвіду
визначення цих характеристик та вітчизняного досвіду, адже ми планували
проведення експериментальних досліджень власного джерела
випромінювання, що відповідало б світовому рівню.
У третьому розділі ми навели приклади трьох джерел освітлення з
зазначенням світлотехнічних характеристик. Ми зазначили спектральні
характеристики для кожного джерела освітлення.
У четвертому розділі ми навели матеріали, щодо побудови нами оптико-
електронної вимірювальної системи. Свою вимірювальну систему для
визначення геометричних розмірів мікрометричного діапазону, ми
спроектували на базі оптичного мікроскопу, телевізійної камери, що
закріплювалась до тіла оптичного мікроскопу з застосуванням перехідників
(тубусів). Отримане, CCD матрицею телевізійної камери, випромінювання від
об’єкту дослідження геометричних розмірів, надходило до персонального
комп’ютеру з необхідним програмним забезпеченням, що дозволило нам за
випромінюванням визначати розміри об’єкту або дефекту об’єкту. Хочемо
зазначити, що програмне забезпечення ми в магістерській дисертації не
розробляли, а користувались готовим програмним продуктом. Адже такого
завдання перед нами не стояло. Більшість наших зусиль було спрямовано на
дослідження джерела освітлення. Проте, хочемо зазначити, що після
отриманих результатів щодо дослідження світло-технічних характеристик
нового джерела освітлення, ми провели ряд вимірювань геометричних
розмірів у мікрометричному діапазоні. Щоб порівняти точність вимірювання
мікрометричних геометричних розмірів. Для цього ми проводили
вимірювання на еталонному зразку лінійних геометричних розмірів ГОСТ
15114-78 Даний комплект мір використовують встановлення роздільної
здатності телескопічних систем, кутові геометричні розміри ми не
вимірювали.
Хочемо зазначити, що ми обрали у якості нового джерела освітлення
світлодіодну лампу та порівнювали отримані результати світлотехнічних
характеристик з джерелом, що є стандартним (базовим) для моделі оптичного
мікроскопу. Отже нами проведено ряд експериментальних досліджень
світлотехнічних характеристик найпопулярнішого джерела освітлення -
світлодіодної ламп. Аналіз результатів дослідження показав, що перед тим як
застосовувати лампу масового виробництва виготовлену за будь-якою
технологією у вимірювальній системі (оптико-електронна система) необхідно
після спеціалізованого дослідження у центрах випробувань і діагностики
надпровідникових джерел світла та освітлювальних систем. Адже зазначені
світлотехнічні характеристики від виробників не відповідають тим, що
визначено дослідним шляхом.In this master's dissertation an analytical study of the structure of the optoelectronic measuring system, its components and features of the setting. From the topic of the dissertation "Improving the accuracy of measuring the geometric dimensions of the micrometric range by improving the lighting unit of the optoelectronic system" it is clear that by improving the accuracy of measuring geometric dimensions in the micrometric range is improving the light source. We have identified the main known methods for determining the lighting characteristics of light sources in the second section of the dissertation. In this section we analyze the methods of "integrating sphere" and "goniophometric" to determine the luminous flux of lighting systems with different types of light distribution. Of course, we considered the methods of world experience in determining these characteristics and domestic experience, because we planned to conduct experimental studies of our own radiation source, which would correspond to the world level. In the third section, we gave examples of three light sources with lighting characteristics. We noted the spectral characteristics for each light source. In the fourth section, we presented materials on the construction of our optoelectronic measuring system. We designed our measuring system to determine the geometric dimensions of the micrometric range on the basis of an optical microscope, a television camera, which was attached to the body of the optical microscope using adapters (tubes). The radiation received from the geometric dimensions object by the CCD matrix of the television camera was sent to a personal computer with the necessary software, which allowed us to determine the dimensions of the object or the defect of the object by the radiation. We would like to note that we did not develop the software in the master's dissertation, but used the finished software product. After all, we did not face such a task. Most of our efforts have been focused on researching the light source. However, we would like to note that after the results obtained on the study of lighting characteristics of the new light source, we conducted a series of measurements of geometric dimensions in the micrometric range. To compare the accuracy of measuring micrometric geometric dimensions. To do this, we performed measurements on a reference sample of linear geometric dimensions GOST 15114-78 This set of measures uses the establishment of the resolution of telescopic systems, we did not measure the angular geometric dimensions. We would like to note that we chose an LED lamp as a new light source and compared the obtained results of lighting characteristics with a source that is standard (basic) for the optical microscope model. Therefore, we conducted a number of experimental studies of the lighting characteristics of the most popular light source - LED lamps. Analysis of the results of the study showed that before using a mass-produced lamp made by any technology in a measuring system (optoelectronic system) it is necessary after a specialized study in the centers of testing and diagnostics of superconducting light sources and lighting systems. After all, these lighting characteristics from the manufacturers do not correspond to those determined experimentally. Although the characteristics of the LED lamp were not significantly different from the halogen lamp. The impact on the measurement accuracy of the optoelectronic measuring system of these light sources, we determined using a bar measure of absolute contrast and concluded that the efficiency of LED lighting is four times higher than halogen lighting when building a measuring system as described in dissertation.
6
Motley, Shane Michael. "Total lightning characteristics of ordinary convection." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1735.
Повний текст джерела
7
Steiger, Scott Michael. "Thunderstorm lightning and radar characteristics: insights on electrification and severe weather forecasting." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4684.
Повний текст джерелаАнотація:
Total lightning mapping, along with radar and NLDN cloud-to-ground lightning
data, can be used to diagnose the severity of a storm. Analysis of the 13 October 2001
supercell event (Dallas-Fort Worth, Texas), some supercells of which were tornadic,
shows that LDAR II lightning source heights (quartile, median, and 95th percentile
heights) increased as the storms intensified. Most of the total lightning occurred where
reflectivity cores extended upwards and within regions of reflectivity gradient rather
than in reflectivity cores. A total lightning hole was associated with an intense, nontornadic
supercell on 6 April 2003. This feature was nonexistent from all supercells
analyzed during the 13 October case.
During tornadogenesis, the radar and LDAR II data indicated updraft weakening.
The height of the 30 dBZ radar top began to descend approximately 10 minutes (2
volume scans) before tornado touchdown in one storm. Total lightning and CG flash
rates decreased by up to a factor of 5 to a minimum during an F2 tornado touchdown
associated with this storm. LDAR II source heights all showed descent by 2-4 km during a 25 minute period prior to and during this tornado touchdown. This drastic trend
of decreasing source heights was observed in two tornadic storms prior to and during
tornado touchdown, but did not occur in non-tornadic supercells, suggesting that these
parameters can be useful to forecasters. These observations agree with tornadogenesis
theory that an updraft weakens and the mesocyclone can become divided (composed of
both updraft and downdraft) when a storm becomes tornadic.
LDAR II source density contours were comma-shaped in association with severe
wind events within mesoscale convective systems (MCSs) on 13 October 2001 and 27
May 2002. This signature is similar to the radar reflectivity bow echo. Consistent
relationships between severe weather, radar and lightning storm characteristics (i.e.,
lightning heights) were not found for cells within MCSs as was the case for supercells.
Cell interactions within MCSs are believed to weaken these relationships as reflectivity
and lightning from nearby storms contaminate the cells of interest. It is also more
difficult to clearly define a cell within an MCS.
8
Teschan, Paul Erhard. "Determination of lightning characteristics through the use of electromagnetic field data." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277252.
Повний текст джерелаАнотація:
In this thesis we determine the electromagnetic fields of a current distribution located, in free space, above a perfectly conducting plane earth. Then we consider the inverse problem of determining the source distribution from the fields. Formulae are obtained for the volume integral (dipole moment) of the current density of a small current source in terms of the fields and known functions. If field data are measured (from lightning over sea water for example) the dipole moment of the current density producing the fields may be found. The validity of the small source approximation used in this work is also established. Finally, a method is developed for determining the average current at points on a vertical line current source, a common model for a lightning return stroke. We treat the source as a string of dipoles and apply a method of constrained inversion.
9
Bailey, Matthew A. "Investigating Characteristics of Lightning-Induced Transient Luminous Events Over South America." DigitalCommons@USU, 2010. http://digitalcommons.usu.edu/etd/667.
Повний текст джерелаАнотація:
Sprites, halos, and elves are members of a family of short-lived, luminous phenomena known as Transient Luminous Events (TLEs), which occur in the middle atmosphere. Sprites are vertical glows occurring at altitudes typically ranging from ~40 to 90 km. In video imagery they exhibit a red color at their top, with blue tendril-like structure at low altitudes. Elves are disk-like glows that occur at the base of the ionosphere, with diameters of ~100-300 km, and have very short lifetimes (~2-3 ms). Halos are diffuse glows that occur at low altitudes, have diameters <100 km, and have a duration that may last up to 10s of ms.
A majority of the studies of TLEs have taken place over the Midwestern U.S. where they were first discovered. This area produces large thunderstorms, which in turn generate large lightning discharges that have been associated with the formation of TLEs. Studies have used the low frequency radiation that initiates with these strokes to study characteristics of these events. This low frequency radiation has been used to determine where large numbers of TLEs may occur. Extreme southern Brazil is a region of the globe believed to have many TLEs, but few studies on these phenomena.
Two collaborative campaigns involving Utah State University proceeded in 2002-2003, and in 2006. Multiple TLE images were made, proving this is, indeed, a region of the globe where these types of events are prominent. In particular, one storm in February 2003 produced over 440 TLEs imaged by USU video cameras. Of these events, over 100 of them had associated halos. Statistical studies for halos previously had been performed in the U.S., but never abroad. Also, several events from the February storm have been associated with negative cloud to ground lightning, a surprising occurrence, as to date, less than a handful of such events have ever been witnessed or published.
In analyzing the TLEs from this campaign, we have shown the halos are similar to those seen in the U.S., even though the storms may be somewhat different. Also, detailed analyses of the negative events show both temporal and spatial morphology heretofore never reported on.
10
Barnum, Benjamin Heath. "Electromagnetic and optical characteristics of lightning measured in the earth's ionosphere /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/6843.
Повний текст джерела
11
Hodapp, Charles Lee. "The evolution of total lightning and radar reflectivity characteristics of two mesoscale convective systems over Houston, Texas." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2422.
Повний текст джерела
12
Esa, Mona Riza Mohd. "Temporal and Wavelet Characteristics of Initial Breakdown and Narrow Bipolar Pulses of Lightning Flashes." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-233671.
Повний текст джерелаАнотація:
Temporal and wavelet characteristics of initial breakdown pulses are meticulously studied especially during the earliest moment of lightning events. Any possible features during the earliest moment that may exist which lead to either negative cloud-to-ground (CG), positive cloud-to-ground, cloud or isolated breakdown flashes in Sweden are investigated. Moreover, the occurrence of narrow bipolar pulses (NBPs) as part of a CG event that has been recorded from tropical thunderstorms are also included in the investigation. Electric field signatures selected from a collection of waveforms recorded using fast electric field broadband antenna system installed in Uppsala, Sweden and Skudai, South Malaysia are then carefully analyzed in order to observe any similarities or/and differences of their features. Temporal analysis reveals that there are significant distinctions within the first 1 ms among different types of lightning flashes. It is found that a negative CG flash tends to radiate pulses more frequently than other flashes and a cloud flash tends to radiate shorter pulses than other flashes but less frequently when compared to negative CG and isolated breakdown flashes. Perhaps, the ionization process during the earliest moment of negative CG flashes is more rapid than other discharges. Using a wavelet transformation, it can be suggested that the first electric field pulse of both negative CG and cloud flashes experiences a more rapid and extensive ionization process compared to positive CG and isolated breakdown flashes. Further temporal analysis on NBPs found to occur as part of CG flashes show the disparity of the normalized electric field amplitude between the NBPs prior to and after the first return stroke. This indicates that the NBPs intensities were influenced by the return stroke events and they occurred in the same thundercloud. The similarity between the temporal characteristics of NBPs as part of CG flashes and isolated NBPs suggests that their breakdown mechanisms might be similar.
13
Nag, Amitabh, and Kenneth L. Cummins. "Negative first stroke leader characteristics in cloud-to-ground lightning over land and ocean." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/623001.
Повний текст джерелаАнотація:
We examine downward leader characteristics for negative first return strokes, along with estimated first stroke peak currents, for lightning occurring over land and ocean reported by the U. S. National Lightning Detection Network (NLDN). For the first time, to the best of our knowledge, we report independent evidence that supports the observations by lightning locating systems of higher first stroke peak currents for lightning occurring over ocean than land. We analyzed lightning occurring in five circular regions, each with 50 km diameter. In western Florida, the median stepped-leader duration was 17% shorter over ocean than over land and in eastern Florida the median durations were 21% and 39% shorter over two oceanic regions than over land. We infer that the shorter durations over ocean simply reflect the higher (25% in western Florida and 11%-16% in eastern Florida) oceanic return stroke peak currents reported by the NLDN. These findings indicate that the cloud charge structure for (at least some) oceanic storms are different than those for storms over land. The percentage of flashes that had at least one NLDN-reported negative cloud pulse prior to the first negative cloud-to-ground stroke was found to be about the same over land and ocean. Using regression analysis, we found no evidence that the relationship between leader duration and first return stroke peak current is different over land and ocean.
14
Gerini, Francesco. "Locating lightning strikes and flashovers along overhead power transmission lines using electromagnetic time reversal based similarity characteristics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Знайти повний текст джерелаАнотація:
Questo lavoro di tesi si pone l’obiettivo di analizzare, verificare e implementare un nuovo metodo per la localizzazione di guasti in rete e fulminazioni basato sulla teoria ”Electromagnetic Time Reversal”. L’applicabilità della teoria è inizialmente discussa, successivamente utilizzando le classiche equazioni delle linee e le basi della teoria EMTR viene proposta una soluzione analitica per la localizzazione del guasto e/o della fulminazione. La accuratezza del metodo utilizzato viene discussa in relazione al numero di misure necessarie alla localizzazione mettendo in evidenza pro e contro rispetto alle tecniche attuali. Viene in seguito presentato un secondo metodo di localizzazione anch’esso basato sulla teoria EMTR ma non ancora verificato su un grande numero di casi, chiamato Similarity Property Method. Utilizzando il software EMTP per l’analisi di transitori e con l’ausilio di MatLab entrambi i metodi vengono testati su diverse tipologie di reti e con diverse condizioni al contorno. Infine una analisi conclusiva viene proposta, indicando come e se i metodi presentati possono essere da considerare migliorativi delle attuali tecniche di localizzazione di guasti e/o fulminazioni.
15
Jurecka, Joseph William. "An evaluation of lightning flash characteristics using LDAR and NLDN networks with warm season southeast Texas thunderstorms." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85994.
Повний текст джерелаАнотація:
A comparison of flash parameters from the National Lightning Detection
Network (NLDN) is made with data obtained from the Houston Lightning Detection and
Ranging II (LDAR) network. This research focuses on relating the peak current and
number of strokes in a negative flash (multiplicity) of lightning with the spatial extent
and mean altitude of three-dimensional lightning in 1407 flashes as mapped by the
LDAR network. It is shown that increasing negative multiplicities over the range two
through ten exhibit, on average, a higher flash extent with higher multiplicities. Singlestroke
flashes have mean heights of nearly 2 km greater. Higher order multiplicities (2
to 10+) were correlated with mean source heights near 8 km. Increasing multiplicity
tends to be associated with greater flash extents increasing more horizontally than
vertically with a 50% to 70% increase in flash extent. No obvious relationship between
peak current and flash extent was observed. Examining peak current and mean height
shows that low current flashes (<10kA) exhibit higher mean heights. However, this may
be due to intra-cloud only flashes being reported as cloud to ground events by the
NLDN. Bipolar flashes do not show much variation with height and flash extent with the exception of negative-first bipolar flashes, which exhibited mean flash extents twice
that of other types. Finally, the flash detection efficiency is 99.7% within 60 km of the
network center.
16
Anderson, Holly Alison. "Characteristics of decaying storms during lightning cessation at Kennedy Space Center and Cape Canaveral Air Force Station." Tallahassee, Florida : Florida State University, 2010. http://etd.lib.fsu.edu/theses/available/etd-12162009-093114/.
Повний текст джерелаАнотація:
Thesis (M.S.)--Florida State University, 2010.Advisor: Henry E. Fuelberg, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed on July 15, 2010). Document formatted into pages; contains xii, 62 pages. Includes bibliographical references.
17
Eritt, Michael. "Großflächige Abscheidung organischer Leuchtdioden und Nutzung optischer Verfahren zur in situ Prozesskontrolle." Doctoral thesis, Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-63184.
Повний текст джерелаАнотація:
In der vorliegenden Arbeit wird die großflächige Abscheidung von organischen Leuchtdioden (OLED) für Beleuchtungsanwendungen in einer neuartigen Beschichtungsanlage vorgestellt. Ausgehend von den speziellen Anforderungen an gleichförmige Schichtdickenverteilung und hohe Abscheideraten für die organischen Schichten, sind die Verfahren der thermischen Vakuumverdampfung (VTE) und der organischen Dampfphasenabscheidung (OVPD) auf Substraten der Größe 370 x 470 mm² unter Fertigungsbedingungen kombiniert. Die Quellensysteme der Anlage wurden hinsichtlich der Verteilung des Materialauftrages und der Oberflächenrauigkeit qualifiziert. Die Kontrolle der Schichteigenschaften ist bei der organischen Dampfphasenabscheidung durch Variation der Parameter Substrattemperatur und Abscheiderate in einem weiten Bereich möglich. Die in situ Kontrolle der Schichtdicke mittels spektroskopischer Reflektometrie wird vorgestellt. Ein Messsystem ist in die Beschichtungsanlage integriert und abgeschiedene Schichten charakterisiert worden. Die Arbeit zeigt, dass die genaue Bestimmung der Dicke einzelner Schichten oder ganzer Schichtstapel mit diesem Verfahren möglich ist und zur ex situ Ellipsometrie vergleichbare Ergebnisse liefert. Um robuste OLED-Bauelemente herzustellen, wird eine organische Kurzschlussunterdrückungsschicht eingeführt, die konform mittels der OVPD-Technologie abgeschieden wird. Die strombegrenzenden Eigenschaften dieser Schicht wirken Defektströmen innerhalb der OLED entgegen. Die reproduzierbare Herstellung von 100 x 100 mm² großen, weißes Licht emittierenden OLED-Modulen mit mittleren Leistungseffizienzen von über 13 lm/W zeigt das Potential dieser TechnologieThe thesis deals with the large area deposition of organic light-emitting diodes (OLED) for lighting applications with a novel deposition tool. The special needs of film thicknesses homogeneity and high deposition rates for organic layers request the combination of thermal vacuum deposition (VTE) and organic vapour phase deposition (OVPD) processes to fabricate OLEDs on 370 x 470 mm² substrates. The deposition sources are qualified regarding layer homogeneity and morphology of the deposition processes. The layer properties are controlled in a wide range by the variation of the organic vapour phase deposition parameters: substrate temperature and deposition rate. The in situ determination of the substrate thickness is shown by the application of spectroscopic reflectometry. The thesis demonstrates the thickness analysis of single and multi-layer stacks by reflectometry. The data fit well to ex situ ellipsometry. Robust OLED devices with an additional short-circuit protection layer deposited by OVPD technology are introduced. The current limiting properties of this layer reduce the leakage currents in the OLED device. The fabrication of 100 x 100 mm² white emitting OLED modules with power efficiencies about 13 lm/W shows the great potential of the manufacturing technology
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Hayakawa, Naoki, Yuichiro Yoshitake, Naoto Koshino, Toshiaki Ueda, and Hitoshi Okubo. "Impulse partial discharge characteristics and their mechanisms under non-uniform electric field in N/sub 2//SF/sub 6/ gas mixtures." IEEE, 2005. http://hdl.handle.net/2237/6847.
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Li, Yu-Ku. "Study of the influence of altitude on the characteristics of the electrical arc on polluted ice surface = L'étude de l'influence de l'altitude sur les caractéristiques de l'arc électrique à la surface de glace polluée /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2002. http://theses.uqac.ca.
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Pokorný, Marek. "Charakterizace vlastností fotovoltaického systému." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219073.
Повний текст джерелаАнотація:
The aim of this work is informed first about photovoltaics universally, works to inform the photovoltaic panels and complete plants. The work also includes instructions on how to implement PVP in accordance with law. Another part is the rough draft of the photovoltaic power 30 kWp, which can be placed on the house, computation and calculation of investment and them profitable investments to time. Design is made in two separate forms of the Fronius Solar and Sunny Design, their outputs are compared. The practical part of this work cooperates with the company SOLARTEC Ltd. for experimental measurements of the photovoltaic system and develop a methodology for setting the properties of real solar systems in operation from the measured data then stored in a database. These data further evaluate and compare the similar operating conditions. This data will show as the course of production of electricity during the typical day in percentage terms, depending on the incident irradiance, cell temperature, angle of incident radiation, etc. We can compare what it looks like an ideal day in terms of production of photovoltaic power, with the other days. Further are in work mentioned histograms achievement panel behind classical day and behind all - time investigation.
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Hsu, Tzu-hsun, and 許梓恂. "Optimization on Color Characteristics for LED Lighting System." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/96943935275128276511.
Повний текст джерелаАнотація:
碩士國立中央大學
光電科學研究所
93
Recently, advances in materials and manufacture have resulted in the commercial availability of light emitting diode (LED) with high luminance and dominant wavelengths spanning the entire visible spectrum. The applications of LED in illumination are up roaring, and solution with color properties, luminous efficacy, color rendering, color temperature, etc. are in urgent need. Therefore, an effective method for optimizing any color properties we require is very critical and necessary. To study new material of phosphor to combine with the LED chip or new LED structure to emit different spectrum could improve them. In addition, to combine with different kind of LEDs could achieve the same purpose and even with much lower cost. In this thesis, it has developed such an optimization method for combination with different color LEDs. This method allows for deriving the optimal mixing ratio of luminance of each LED in order to obtain the best color properties for illumination. By using this optimization method, a white LED whose color temperature (CT) is approximately 6500 K and color rendering index (CRI) is 70, can be improved its CRI better than 80 and its correlated color temperature (CCT) down to near 3000 K simultaneously. Moreover, it could produce one which is more close to the warm-white lighting, and it is possible to substitute for the incandescent lamp. Besides, the best color luminous efficacy could be also evolved from this optimization method while CRI is good enough to apply for indoor lighting. To structure an adjustable standard daylight source and to deal in a trad-off color gamut and luminous efficacy of display backlight are also able to use in this optimizing method.
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Chun-FuTsai and 蔡均富. "Investigation and Improvement in Optoelectrical Characteristics of III-V Compound Semiconductor Lighting Emitting Diodes." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/53158101177974234546.
Повний текст джерелаАнотація:
博士國立成功大學
微電子工程研究所碩博士班
100
The main purpose of this dissertation is to improve III-V compound semiconductor light-emitting diodes (LEDs) by chip process techniques and roughened/patterned sapphire substrates (PSSs). The investigation of chip process techniques includes current blocking layer (CBL) design, surface-roughening of chip, sidewall treatment of chip, and different structures of chip form. The investigation of roughened/patterned sapphire substrates, we utilized the roughening treatment on planar and patterned sapphire substrates, and formed patterns with different refractive indices on sapphire substrates. In respect of research on applying current blocking layer (CBL) to improve GaN-based LEDs, in the first part, we successfully spun SiO2 nanoparticles onto the surface of GaN LEDs as the CBL by spin coating and high temperature baking, instead of plasma-enhanced chemical vapor deposition (PECVD). Here the light output power was increased by 15.7% at 20 mA. In the second part, we utilized one-step process to fabricate CBL with Schottky contact, the light output power was increased by 16.3% at 20 mA. In the third part, we combined conventional CBL with highly reflective aluminum layer to reduce the light absorption loss at opaque electrode. The light output power was further increased by 25.8% at 20 mA. In respect of research on applying surface-roughening of chip to improve AlGaInP-based LEDs, we spun SiO2 nanoparticles onto the surface of LEDs and utilized inductively coupled plasma (ICP) to etch p-GaP surface to increase the light extraction. From measurements at 20 mA, we can get 8% to 46% enhancement in luminous intensity and 3.5% to 31.5% enhancement in light output power. In respect of research on applying sidewall treatment of chip to improve GaN-based LEDs, in the first part, we utilized wet chemical etching on GaN LEDs sidewall by 60 °C KOH solution. The light output power was increased by 17.3% at 20 mA and the reverse leakage current was decreased from 230 nA to 40 nA at -5 V. In the second part, we utilized sidewall treatment without etching to form silver micro-pillar array around chip. We can get 22% enhancement in light output power at 20 mA. In respect of research on applying different structures of chip form to improve GaN-based LEDs, in the first part, we formed micron deep hole array structure around chip and on chip by ICP dry etching, we can respectively get 5% and 14.4% enhancement in light output power at 20 mA, without electrical degradation. In the second part, we fabricated chip with hexagonal array of micro-pillar structure by ICP dry etching, which is beneficial for direct extraction of photon and reduction in view angle. From measurements at 20 mA, we can get 26.3% enhancement in luminous intensity and 13.4% enhancement in light output power. In respect of research on applying roughened/patterned sapphire substrates to improve GaN-based LEDs, in the first part, we successfully fabricated planar and patterned sapphire substrates with random nano-roughening surface by Ni cluster and ICP dry etching. Besides improvement in crystal quality, as compared to GaN LEDs grown on conventional planar sapphire substrates, the light output power of GaN LEDs grown on roughened planar sapphire substrates was increased by 7.9% and 21.3% at 20 mA ; as compared to GaN LEDs grown on conventional patterned sapphire substrates, the light output power of GaN LEDs grown on roughened patterned sapphire substrates was increased by 7.3% and 11.4% at 20 mA. In the second part, we fabricated GaN LEDs grown on micro-patterned array with different refractive indices (AlN, SiO2, Al2O3, TiO2) by direct heteroepitaxial lateral overgrowth. Besides different view angles, we can get improvement in crystal quality and enhancement in light output power by pattern structures and epitaxial lateral overgrowth mechanism. The light output power of patterns with different refractive indices was increased from 9% to as high as 47.6%.
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DeBauge, Lucia K. "The effects of lighting characteristics on the behavior of elderly residents in an intermediate care facility." 1987. http://hdl.handle.net/2097/22312.
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Hong, Ming-yu, and 洪銘余. "A Study on the Influence of Various Types and Spectral Characteristics of Artificial Lighting for Human Responses." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/05495316871887741509.
Повний текст джерелаАнотація:
碩士國立成功大學
建築學系碩博士班
96
With the demanding for future environment and matching to international tendency, tending towards the energy saving, environmental protection, and diversity, pursuing healthy, comfortably constructed environments, and indoor environmental quality are already becoming the important issue in the 21st century. According to related researchers, different artificial illuminative environment and spectral characteristic will affect psychological and physiological human responses. This study evaluates human psychological responses by means of analysis of the ‘Ryodoraku System’, based on traditional Chinese medicine, reflecting the condition of a sympathetic nervous system. This study probes the influence on the human body of illumination having the color-temperature of 4000°K and 6500°K set in typical Taiwan climatic conditions of summer and winter, with various types of artificial lighting in interior environment. The objective of this study is to find the best working environment and spectrum distribution that could become a reference for designers and users. █ Methods The research utilizes a full-scale laboratory as the environment sensation to evaluate three different artificial illumination environments and their influence on the human body. These three artificial lightings are: a) three wavelength fluorescent lamp, b) full-spectrum fluorescent lamp, c) white LEDs lamp. This study used the SD Method to analyze the effects of psychological responses, the evaluation of physiological responses using Ryodoraku values, and the appraisal of working efficiency used a simple mathematics test. █ Result 1. Based on a review of related researches as well as the analysis of the present experiment, high color-temperature(6500°K) and medium color-temperature(4000°K) light had different influence on human psychology and physiology either in winter or summer. This research had discovered that using white LEDs lamp long time under the high color-temperature light had negative influence on human physiology and psychology, but using full-spectrum fluorescent lamp under the medium color -temperature light had better performance for human responses. It is recommended that it would assure the performance of comfort and health, and promote working efficiency in using full-spectrum fluorescent lamp of color-temperature light (4000°K). 2. Further discussing about the influence on different spectral characteristics of artificial lighting for human responses, we discovered that increase in the spectrum of orange wave (595nm~620nm) energy may enhance comfortable, relaxed feeling and inspire the spirit; But increase in the spectrum of blue wave (435nm~490nm) energy under the color-temperature 6500°K light has significant effects on human body organs correlative to the respiratory and circulatory system, urinary system, and the bilitary system .
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Chang, Shih-Pang, and 張世邦. "The epitaxial growth and device characteristics of novel InGaN/GaN semipolar nano-pyramid LED for next generation solid-state lighting." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/88376843709389466732.
Повний текст джерелаАнотація:
博士國立交通大學
光電工程研究所
102
Based on the concept of compliance growth, we modify the GaN nano-pillar from cylinder into nano-pyramid (NP) and nano-pencil shape, in principle has higher tolerance of stress, try to solve the problem of highly mismatch epitaxy. We focus on the development of novel long emission wavelength nano-LED and high quality high indium content InGaN thin film. In the first part of this thesis, we successfully demonstrate the green, yellow and red NP LED with emission wavelength 524nm, 585nm and 640nm respectively. The green NP LED shows a external quantum efficiency (EQE) 2.4% under current density 30A/cm2. The EQE would sustain at the maximum status once reaching the peak value till high current density 170A/cm2, which means the efficiency droop is 0% from peak value. This is due to the B coefficient of NP LED is 5 times higher than conventional planar c-plane LED, enhancement from 1x10-11(cm3/s) to 5x10-11(cm3/s). Besides the demonstration of high quality green NP LED, by integrating two emission colors vertically in one NP LED, we not only successfully develop a high quality single color red NP LED, but also demonstrate two emission peaks in single NP LED. Under current density 170A/cm2, we achieve a warm white light source with correlated color temperature (CCT) 4489k, and its coordinates CIE x and CIE y at 0.385 and 0.5 respectively. As a result, the NP LED demonstrates new possibilities for long emission wavelength light source. In the second part of thesis, according to the concept of compliance growth, we try to create new solutions to develop high quality InN crystal, which is the most difficult material of III-Nitride family. By covering the bottom area in between GaN nano-pillars with SiO2, the substrate became the sidewall passivated GaN nano-pillar (SPGP) template; the InN crystal would only grow on certain positions of intersections of different plane. By utilizing the COMSOL simulator, from the results of stress distribution, there is a common phenomenon of these intersection areas. The underlying GaN has higher degree of freedom to accommodate the lattice vertically or horizontally that generates from InN/GaN interface. Although there is a strain selected growth behavior, nevertheless, the loading effect facilitates the growth to happen at the edge of SiO2 mask that becomes a competing position with strain selected growth during the nucleation. In order to create some regular rules, we intentionally change the nano-pillar from cylinder shape into pencil like appearance with specific facets such as {10-10} M-plane and {10-11} S plane, and enlarge the diameter a little bit to eliminate certain un-controllable growth position. It becomes more difficulty for InN to grow on GaN nano-pencil. We must lower the growth temperature to obtain similar amount of InN crystals., which means that the regulation on cylinder shape nano-pillar is promoted by the rough surface not a predictable result. After changing the cylinder shape into pencil appearance, an interesting phenomenon has been observed while growing InN crystal on to SPGP template. The six corners of GaN nano-pencil seem to be the favored positions for InN to grow first, which correspond to the intersection of sidewall m-plane and the intersection of m-plane and s-plane. The simulation results show a good agreement with what we observed from SEM images; the strain energy of the corner position is nearly eight times lower than other surface on the nano-pencil. From the results of COMSOL simulator, the mechanism is very similar of InN on nano-pillar and nano-pencil; the intersection area is the lowest strain energy position in the system. Taking InN with an average thickness 10nm as an example, the lowest strain energy is 17 J/m2 which is 6~9 times lower than grown on S-plane (102 J/m2) and M-plane (151 J/m2). As a result, there is a self-assembly regular growth behavior occurred and would be more pronounced if the diameter of nano-pillar becoming wider. The GaN nano-pencil is almost defect free under TEM image and the single crystal InN is observed from selective area diffraction pattern which has the same orientation with GaN nano-pencil. The internal quantum efficiency (IQE) of InN grown on flat c-plane GaN and on SPGP is 3% and 6% respectively, and the IQE has a relatively 100% enhancement while InN grown on GaN nano-pencil. In short, by extending the concept of compliance growth, we successfully demonstrate InGaN based green, yellow and red NP LED, and successfully grow single crystalline InN overcoming the highly mismatch between InN and GaN by nano-epitaxy. There is a pronounced self-assembly growth phenomena at specific locality on GaN nano-pencil, which is assisted by the highly mismatch between epi-layer and substrate. Therefore, nano-epitaxy on one hand is a promising solution to solve the efficiency green gap as well as solid-state lighting. On the other hand, the strain-assisted growth behavior is potential method to grow InGaN based low dimensional structure, such as quantum dot and quantum wire, to explore more possibility of room temperature single photon source and advanced nano-device in the future.
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Cherng, Chii-Rong, and 程啟榮. "Lighting Characteristics Study of Taiwan Traditional Temples from the Cultural Ideology (A Case Study of Long-Sham Temple in Lukang)." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/03117705742163050801.
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Chiu, Ching-Hua, and 邱清華. "Study of Nanofabrication Techniques and Device Characteristics of High Efficiency GaN-based Light Emitting Diodes for Next-generation Solid State Lighting." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/40081132957629905118.
Повний текст джерелаАнотація:
博士國立交通大學
光電工程系所
98
Recently, Nitride (III) light-emitting diodes (LEDs) with emission wavelength ranging from ultraviolet to the short-wavelength part of the visible spectrum have been intensely developed in the past 10 years. Due to the rapid developing in efficiency improvement, applying the opto-electronic device such as LED, laser and photo-detectors into our life becomes possible. Besides, because of the next generation application in optical storage, flat display, bio-detection and general lighting, the research about GaN lighting devices attracted more and more attentions. In this study, we mainly focus on developing GaN nano structures and applying these nano structures on GaN LED. The device fabrication process, efficiency improvement, material and opto-electronic characteristics of the nano-structured GaN-based LEDs will be also discussed. The entire dissertation could be divided into four parts. The first is developing a novel GaN nano structure fabrication process. By well control the metal depositing thickness, annealing temperature, etching conditions, we could achieve different length and diameter GaN nanorod arrays. The emission and anti0refelction characteristics of the fabricated nanorod structures will be discussed. Besides, we applied the valence force field model to help us to realize the influence of strain relaxation within GaN multiple quantum wells (MQWs). The second part of this dissertation is applying these nano structures on the surface of GaN-based LEDs to improve the lighting efficiency. We first utilizing etching method assisted by spinning nano spheres on device surface serving as masks to form high-aspect-ratio GaN nanorods. However, considered the possible deterioration of reduced current spreading paths, we then adopted a bottom-up method to synthesize ZnO nanorod on the surface to suppress the total internal reflection and improve the light extraction efficiency. The third method we used to improve the device performance is combing the overgrowth technique on nano-patterned sapphire substrate to improve the internal quantum efficiency (IQE) and light extraction efficiency simultaneously. At the later half of this dissertation, we focused on the studying of the IQE performance of GaN-based LEDs. We grow our LED structure on the patterned sapphire substrate (PSS) and an increment in IQE is expected. In the third part of this study, we modified the traditional method for IQE measurement. We firstly modify the excitation laser wavelength and a serious of power and temperature dependent study was performed to define the IQE of LED device. The internal carrier lighting mechanism was also studied. The last part of this dissertation is based on the third part but a electrical injection setup was established. This instrument enabled us doing a serious of temperature and injection current dependent measurement. It not only helped us understand more about the IQE, but also well for discovering the origins of efficiency droop phenomenon. Besides, simulation software of APSYS was also performed to simulate the device performance under different temperature. The output of this dissertation provided a great help on realizing the solid state lighting in next generation.
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Liang, Jui-Kai, and 梁瑞凱. "Study on the growth characteristics of cutting lettuce under different lighting conditions inside the carbon container-like plant factory with artificial lights." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/50643175318104049292.
Повний текст джерелаАнотація:
碩士國立屏東科技大學
生物機電工程系所
104
The aim of this thesis is to investigate the LED light quantity on the lettuce growth conditions within a cabin-like plant factory. There are six different LED lamps with light spectrum and intensity. The open and close time of LED lamps is controlled as 14 to 10 hours. The deep water hydroponic cultivation system is employed and the target plant is lettuce. The chemical composition of nutrition is based on Taichung Distric Agricultural Research and Extension Station suggested. All measures are performed in a fixed micro-environment but changed the light conditions for six cultivated beds. The fresh weight, number of leafs, total leaf area, and ionic concentrations of lettuce are detected during growth period for further analysis. Results indicated that the micro-environment factors, such as air temperature, relative humidity and CO2 concentration, and pH as well as EC values are along an acceptable trend during lettuce growth. The LED light spectrum with more portion of 740 nm red light results in a significant enhancement in biomass of lettuce for present work.
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Teng-TaiWu and 吳嶝岱. "A Study of the Relationships among Product Characteristics,Perceived Valued of Products, Customer Satisfaction, and Customer Loyalty-An LED Indoor-Lighting Applied in Taiwan." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/18276827776928365572.
Повний текст джерелаАнотація:
碩士國立成功大學
高階管理碩士在職專班(EMBA)
100
Abstract LED (Light Emitting Diode) semiconductor light source, in addition to long life, less heat, less maintenance, and many advantages such as light color variable, the more important features is a huge energy saving potential. LED indoor lighting products include lamps,light bulbs and lighting group products are starting to produce shelves. However, because of high prices, the products are an integral market for many years, market growth has been limited.In recent years, especially in the past two years, save energy and reduce carbon demand, growth and acceptance improved significantly in Europe and the United States, have been widely used in Japan, the Taiwanese in the accomplishment of life and standard of living compared to Europe and the United States is not anxiety more so, the application of LED indoor lighting products imported should significantly the growth and development. This point in the End-Users-side focus on product characteristics or value of acceptance and trade-offs should understand exactly what to respond effectively to market trends. This paper attempts to the customer on product characteristics, the perceived value of products to determine product satisfaction measure and a possible product loyalty, particularly to the marketing point of view as the main direction, through the end of the operation of the customer to inquire about the current LED acceptance of indoor lighting products in the market, trying to figure out the fancy and focus on the customer focus, providing the industry regardless of the direction of research on new products, or marketing of follow-up LED market focus reference. The scope of this study is B to C (Business to Customer) for the object not limited to LED related practitioners, non-specific ethnic groups from all sectors of society through a series of questionnaires to obtain his / their views and ideas, and conclusions are as follows: 1. Product features product satisfaction significantly in the epidemic (Fashion). 2. Product characteristics of the product perceived value have a significant effect. 3. Product characteristics have a significant effect on products perceived value. 4. Products perceived value on customer satisfaction have a significant effect. 5. Products perceived value have a significant effect on customer loyalty. 6. Customer satisfaction have a significant effect on customer loyalty. 7. No significant differences in demographic variables in product features, product perceived value, product.
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Rudlosky, Scott David. "Characteristics of positive cloud-to-ground lightning." 2007. http://etd.lib.fsu.edu/theses/available/etd-07052007-173036.
Повний текст джерелаАнотація:
Thesis (M.S.)--Florida State University, 2007.Advisor: Henry E. Fuelberg, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed Oct. 11, 2007). Document formatted into pages; contains x, 49 pages. Includes bibliographical references.
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Wu, Lii-Pien, and 吳譯辯. "Lightning Surge Characteristics of Grounding System and Their Affections." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/59671960485389800994.
Повний текст джерелаАнотація:
碩士中原大學
電機工程學系
87
The performance of grounding system is very important to the safety of human and equipments. A grounding system is conventionally characterized by its grounding resistance , but more and more damages occurred on grounding system due to lightning surge can not be evaluated only by using grounding resistance. The thesis analyzes the lightning surge characteristics of grounding system directly form the view point of electromagnetic principles, i.e. analyzes the electromagnetic characteristics of grounding system with respect to the lightning surge current. The analysis items include the potential and electromagnetic fields due to lightning surge current, and next, based on the analysis results , the step voltage and touch voltage related to human safety , and the ground potential rise(GPR) and ground potential difference(GPD) related to equipment protection are analyzed ; from which , we can assess the damages of personnel and equipments on a grounding system. The analysis results have shown that the danger step and touch voltages will be produced to threaten the safety of personnel when the lightning surge current injects into the grounding system, the GPR and GPD will also damage the low voltage and weak systems. These hazards will increase with the increasions of the peak value, wavefront steepness and the duration time of lightning surge current. For protecting personnel, low voltage and weak systems and equipments from the lightning surge current, this thesis proposes two methods namely conduction method and insulation method to enhance the protection performances of grounding system, and this will contribute to upgrading the power quality.
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Lai, Ming-Hong, and 賴明宏. "Lightning Surge Characteristics of Large Grounding System with Multi-grid." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/36348547753833444671.
Повний текст джерелаАнотація:
碩士中原大學
電機工程研究所
89
In this thesis, the lightning characteristics of large grounding system with multi-grid are analyzed based on the electromagnetic theory. The study is aimed to the grounding system in the Mucha factory of Taipei-Rapid-Transit System (TRTS) which is composed of seven ground grids. To study the lightning characteristics of this grounding system, the ground potential rises (GPRs), ground surface potentials, ground potential differences (GPDs) between different grids, step voltages and touch voltages on each grid when the lightning is striking on one of the grids is analyzed and the hazards to personnel and equipments are evaluated. The study will consider that all the grids are connected together and disconnected from each other, respectively. The study results have shown that the GPR, GPD and touch voltages on the grid to be stricken by lightning will be reduced with small degree when all the grids are connected together. These results will contribute to the protections of equipments and the safety of personnel on the grid to be stricken by lightning, but the GPR of step voltage and touch voltages on other grids without lightning striking will be slightly risen. In summary, whether all the grids are connected together or not, the protection measures are still required to enhance the personnel and equipments to protect against lightning. Many protection measures had been proposed by the literatures. This thesis will integrate then and list out for application references.
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Liao, Jin-Hong, and 廖晉宏. "The Development of Phosphate Glass with Low Characteristic Temperatures for Lighting Application." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/00146354025677786880.
Повний текст джерелаАнотація:
碩士國立聯合大學
材料科學工程學系碩士班
103
The LED lighting device and its package are requested for high performance, strengthened thermal and mechanical stability, and improved reliability nowadays for advanced application. Conventional LED lighting package is based on epoxy and silicone for phosphor-conversion, PC, layer. The polymer-based composites easily produce yellowing and degrade significantly in high-power excitation and long term usage. Phosphor- containing glass layer instead of polymer-based composites is one of the important advances in the pursuit for high performance lighting. In present study, the developed phosphate system with functional elements (Al, Li, Na, and Bi) addition exhibits low characteristic temperatures and high optical performance. The 50P2O5-4Al2O3-21R2O-4Bi2O3 (R=Li and Na) glass has low characteristic temperatures of 345 and 383°C for Tg and Td, namely glass transition and dilatometric softening points, respectively. The transmittance of the glasses is higher than 85% in visible region. The glass can keep a similar viscosity-temperature slope as RO-P2O5 glass system in high viscosity region and show an identical gradient as R2O-P2O5 in low viscosity region. The viscosity-temperature behavior of this developed phosphate glass make it suitable for forming. The developed phosphate glasses with low characteristic temperatures is then applied to replace conventionally adopted epoxy matrix in the phosphor containing system. In structure analyses, it reveals that the addition of functional elements link to the phosphate chain as the end group and acted as modifier in the phosphate structure. The P-O-Bi bonds form to replace P-O-Li and P-O-Na with increase in Bi2O3 content. The addition of Bi2O3 successfully enhances the overall bond strength, polarizability, and in turn increases the thermal, optical properties and chemical durability of the developed glass. Glass ceramic phosphor (GCP) layer is formed by the thermally driven-in treatment of YAG phosphors into the designed phosphate glass substrate with various temperature and time parameters. Through SEM observation, the phosphors powders are well distributed in glass substructure surface layer and the maximum thickness of GCP thin layer is around 80 µm. The light emission can be manipulated from blue, white, to yellow with heat treatment time and temperature control. The microstructure, phase distribution about glass/ceramic interaction, and the optical performance of CIE coordinates of the GCP layer are investigated and intensively discussed.
34
McCormick, Tracy Lynn. "Three-dimensional radar and total lightning characteristics of mesoscale convective systems." 2003. http://www.lib.ncsu.edu/theses/available/etd-08042003-035751/unrestricted/etd.pdf.
Повний текст джерела
35
Wang, Ping-Chieh, and 王秉杰. "The study of LED lighting control based on physiological characteristic of human vision." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/qbf7n7.
Повний текст джерелаАнотація:
博士義守大學
電子工程學系
104
Lighting research on saving energy is an important subject. The solid-state lighting has become a famous doctrine to guide the lighting system. The White-light LED has a significant effect on energy saving, since the invention has become an important research. There are many kinds of White-light LED driver method, this dissertation focus on Pulse-Width Modulation (PWM) operation LED lighting, based on human vision characteristics. In this dissertation, not only discuss human vision, also discuss machine vision that mimics human vision. Human vision is very difficult to measure. In this dissertation, we analyzed researches conducted over the past hundred years the medical aspects of ophthalmology and visual, selected the suitable theory for lighting system design. According to the theory of visual physiology, it may be organized into three architectures which are flashing, flicker fusion, and the steady state lit. Similarly, machine vision has a similar structure and three architectures. Machine vision and human vision have some differences. The machine vision character is directly by requirements of the application. According to the related consolidation theory, could supply the experiment and application. And design PC software to expand the data logger function. In order to find suitable for general lighting system design, we do not use the medical level precision test experiment. We use a controllable PWM generator with LED lamp, mounted into semi-enclosed box, with the human eye to observe the phenomenon and then finish the experiments. Experiment environment use two light sources, the purpose is to simulate the indoor lighting. Three experiments: flashing experiment find stimulating the highest degree of parameters; flicker fusion experiments for flashing feeling disappear area; and steady state lighting test to the human eye can''t distinguish the minimum differential duty of the PWM. The summary of experiment: the best warning light frequency located between 7 Hz to 15 Hz; lights for more than 200 Hz, duty adjustment between 10% are the best. Found in early experiment, the relation of LED brightness to PWM driven is not completely linear, and some papers propose the driven current response to brightness can support this argument. Nonlinear brightness in machine vision, such as automatic product checking, will be a hard problem. Therefore, we use the data logger and PC software control, verifies the LED linearity. In order to avoid any circuit effect, we use the simplest driver circuit. LED lamp and brightness meter closed in a small dark room, use PC command PWM generator to set frequency and duty, after waiting for stability, read the intensity of illumination and record. In this experiment process, automatic adjust frequency from 50 KHz to 1 KHz, duty form 90% to 10%. The experiment results showed, the linear area is between 4 KHz to 3 KHz. Due to the lighting equipment and LED are different with our experiment, but can use the method of linearity correction. Finally, this dissertation completed the best lighting for human vision drive, and the best lighting for machine vision driven approach. In the future, if one can explore both, it will be another interesting topic.
36
Hsiao, Sheng-Wen, and 蕭勝文. "The Lightning Characteristics Simulation and Analysis for Extra High Voltage Underground Cable." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/77541003746113128411.
Повний текст джерелаАнотація:
碩士國立高雄應用科技大學
電機工程系博碩士班
96
The power quality of overhead transmission line is easily affected by external factors such as natural disaster (typhoon, earthquake, floods, windstorm, snowstorm and lightning), and man-made factor (project operation, festival color ribbon, etc.) as well as other factor (such as plant height, bird nest, climbing of snake and animal, etc.). In recent years, in order to enhance the electricity quality and to reduce the people’s contend, transmission line is designed with underground approach for urban and science areas. Since the voltage level of cable is increase and transient behavior become sever to seriously affect system reliability. The overhead cable is necessary to conduct toward underground cable, once overhead cable is striking by lightning and its abrupt wave is reaching to the inside of cable; the damage will seriously affect the operation and life of cable. In order to increase the cable operating life, the explore and analysis of lightning abrupt wave is required. This thesis applies the EMTP software tool to establish the equivalent circuit model for underground cable. In order to demonstrate the effectiveness of the proposed model, no. 2 ciaming-south science 345 kv transmission line located at the outlet of southern science park EHV substation with higher cable events is selected as example for computer simulation to explore the correlation between the lightning striking and cable events. The simulation results will suggest installing the arrester at cable connecting station or substation circuit breaker. Moreover, proposed method will apply to other transmission line to enhance the electricity quality and reliability.
37
Hung, Neng-Fa, and 洪能發. "Lightning Characteristics Analysis and Benefit Assessment for Overhead Transmission Line with Line Arresters." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/9vyks9.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
機電整合研究所
101
Most of overhead transmission lines construct along the mountainous terrain or build in open areas. So they are often struck by lightning. Due to the lightning is the main natural disaster to overhead transmission lines. It causes not only power system voltage sag, but the line outages, affecting power quality and supply reliability. According to high-tech industries ’s strict power quality requirement in recent years, although examining the lightning protect measure of existing overhead transmission lines to install lightning arrester can improve power outage and voltage sag which caused by lightning, we must consider its costs and ongoing maintenance costs. So it is necessary to simulate and analysis the lightning characteristic, as a reference for lightning protect measure. In this paper, TFlash program simulates 161kV overhead transmission lines with lightning arrester absorption characteristics. To verify lightning arrester is a very effective lightning protection devices, which can rapidly lead at lightning current to the earth, in order to release a lot of lightning energy, reducing transmission line flashover accident, to avoid voltage dips or power outages affecting power quality and reliability. This paper also discuss the different locations and number of installed lightning protection effectiveness. If not consider the cost, two loops are fully equipped Wiring arresters of the best. If only one back line, the other still unable to prevent insulators flashover. If you choose partial installation, the effectiveness of centralized towers installation is better than separated. When you install, you can choose higher lightning density areas to adopt centralized installation, also can be paired with other measures to improve the thunder lightning harm.
38
Laio, Yu-Hsien, and 廖祐賢. "Lightning Surge Characteristics Analysis for the 161kV Cable Connection Stations and Improvement Strategies." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/69z4w3.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
電資碩士在職專班研究所
102
The lightning characteristics of 161kV cable connection stations(CCS) and the affections are evaluated.The improved strategies are also proposed.The study mainly focus on the analysis of voltage and current variations on the overhead lines,CCS and underground cable relative equipments with respect to the lightning on the overhead ground wire(OGW)and phase conductor,and to evaluate the affections equipments,based on the analysis results. First of all,modeling and simulation of lightning characteristics by alternative transient program(ATP) are presented,in which the 161kV overhead line,CCS and underground cable will be considered in the model.In addition,different lightning currents,different lightning points and different system conditions will be considered for the lightning characteristics simulation.The different system conditions means that different improved strategies which include overhead line with or without line arresters,different tower foot resistances,different numbers of OGW,CCS with or without arresters and tower arms with or without capacitors.Analysis results show that line arresters and reducing tower foot ground resistances are more effective than others for protecting overhead line and underground cable of lightning point on OGW of CCS.While,if lightning point on phase conductors of CCS,to install capacitors between tower arms and reducing tower foot ground resistances are prefer for increasing the protection of underground cables.The study results are valuable for the study of CCS improvement devices in the future.
39
Tzeng, Yi-Neng, and 曾以能. "A Study of Lightning Surge Characteristics and Protection Strategies for a Overhead Transmission Line." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/05480700952294881197.
Повний текст джерелаАнотація:
碩士國立高雄應用科技大學
電機工程系
96
In this thesis,the transient over-voltage phenomenon is simulated by Alterative Transient Program Electromagnetic Transient Program (ATP-EMTP) as a transmission line or tower is struck by a lightning. The models of tower, line and arrester are established, and different protection strategies are added to the simulation system, these strategies include reducing the foot resistance of a tower and installing line arrester,etc. Then the scheme is applied to some 161kV transmission line sections, and the results can be very important reference for other parts of Taipower system to improve stability and power quality.
40
Huang, Chi-Wen, and 黃季雯. "Tone characteristic description and color gamut variation of RGB/RGBW OLED display under ambient lighting conditions." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/54296669083305330876.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
光電工程研究所
101
There are three topics discussed in this thesis. The first topic majorly studied OLED (Organic Light-Emitting Diode) display characteristic under various ambient lighting conditions by using olorimeter. After the measurement, the linear piecewise formula in conjunction with the flare correction is used to describe TRC(tone response curve) under various ambient lighting conditions. The TRCs will be predicted more precisely. The second topic discussed three kinds of RGB to RGBW conversions and used Matlab to fullfill three conversion algorithms. The stimulation included red channel, green channel, blue channel and neutral channel based on different images. The difference images related to their corresponding conversion algorithms will be discussed subsequently. Finally, combined the flare values measuring in the first experiment with the gamut volumes. The cases were discussed whether normalized RGB stage and linear RGB stage could influence the color gamut volumes in RGBW OLED display. The results showed normalized RGB stage can reduce gamut volumes and the linear RGB stage can not.
41
Chuang, Cheng-Yu, and 莊承諭. "Evaluation of Lightning Characteristics on the Different Grounding System Frameworks for Various Voltage Level Substations." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/gba8p7.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
電機工程研究所
105
Nowadays, the smart grid is fast developing in power system. Each voltage level substation needs to install related smart equipments for significant upgrading the performance of substation.The smart equipments include informations, communications, networks, computers, protective relay, and the associated electronic devices, which are all the weak power equipments with lower tolerance of electromagnetic susceptibility (EMS) and more vulnerable to the electromagnetic impacts from high voltage and current in the substation, especially the lightning faults which usually cause to equipment malfunction even damage. The lightning fault are very close related with grounding system, the lightning characteristics of grounding system should be clarified for determing the suitable protection measures to withstand lightning fault. This thesis is mainly aimed at lightning characteristics of substation grounding system from the view point of lightning protection for smart grid weak power equipments. In which, the lightning characteristics of different grounding system frameworks in different substations are analyzed by using the alternative transicent program (ATP) and the grounding system electromagnetic analysis software (CDEGS). The main lightning characteristics of grounding system include ground potential rise (GPR), ground potential difference(GPD), equivalent interference currents and magnetic field distributions which used for evaluation affections on smart weak power equipments. The maximum ground surface potential, touch and step voltages are also analyzed for evaluation the safety of personnel, and the lightning characteristics of different grounding system frameworks of different substations are compared with each other. The study results show that lightning characteristics of some grounding frameworks are better than the existent grounding system framework, this means that the existent grounding system of substation need to improve the protection performance for smart weak power equipments. This study results provides good references for substation grounding system planning and design to increase the protection performance for smart weak power equipments, and thus constibutes to the development of smart grid.
42
Tsai, Wei-Hsuan, and 蔡維軒. "Study on Switching and Lightning Surge Characteristics Analysis and Affection Assessment for Offshore Wind Farm." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/60186555505112431567.
Повний текст джерелаАнотація:
碩士國立中正大學
電機工程研究所
103
In this thesis, the electro magnetic transient program (ATP-EMTP) is used to simulate the transient behaviors of switching surge and lighting surge for offshore wind farm. The Graphical User Interface ATPDraw demonstrates the equipment transient model of the offshore farm. The electrical equipment includes wind generator, wind generator step-up transformer, submarine cable, underground cable, onshore distribution station, circuit breaker, and arrester. Proper system is selected according to the pertinent literature and data provided from the manufacturer for setting the equipment transient models to simulate the switching surge and lightning transient. The simulation is composed of cable system energization, circuit breaker disconnection, fault clearing, lightning surge. The potential transient voltage of all electrical equipment is assessed by the selected BSL of whether it exceeds the specification or not. Lastly, the arrester is assessed of whether or not it can bear the transient energy. The result of this simulation reveals that when increasing the voltage to the operation breaker, there is no obvious increase of the transient overvoltage. However, if increasing voltage when the cable still have residual voltage, the significant increase of transient voltage can be noticed. This significant transient voltage, nevertheless, can be eliminated by the arrester. The lightning simulation indicates that when the wind power plant is struck, the grounding potential of the plant might be rising and influenced as well as the cable system and cause a certain degree of overvoltage.
43
Cheng-HsiKuo and 郭政昕. "The Characteristics of the Sprites and Their Parent Lightning Captured by Taiwan TLE Observation Network." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/w3bpzk.
Повний текст джерелаАнотація:
碩士國立成功大學
物理學系
107
Williams et al. (2007) summazied that more than 99.9% sprites are initiated by positive cloud-to-ground (+CG) and high charge moment change (CMC). After the launch of Formosat-2, the Imager of Sprite Upper Atmosphere Lightning (ISUAL) obtained the sprite globally for the first time and had a chance to investigate their polarities. The result surprisingly indicated that more than 20% of sprite events were triggered by negative cloud-to-ground lightning, totally different from the previous statistic results. Furthermore, most of negative sprites distribute over low latitude, and more than 80% negative sprites appear with halo signatures. The Taiwan optical TLE ground network, which consists of four stations is the only low-latitude observation facility in the world, and is capable to validate the above conclusions and explore the polarity of sprite around Taiwan with the assistance of the Lulin ELF obversations. In this study, 813 sprite events captured by Taiwan optical TLE ground network from 2015 to 2016 are carefully analyzed. 15 negative sprites, approximately 1.85% of all events, were identified. Although the ratio of the negative sprite is less than the result obtained by ISUAL, this ratio is still significantly higher than the finding proposed by Williams et al. In the identified negative sprites, more than 27% events appeared with halo signatures, and 8 events appear in groups and the morphology of them is columnar. The derived CMCs of the sprites demonstrates that the CMC of negative sprites is averagely lower than the one of the positive sprites, and it is consistent with the finding by ISUAL observation. These results reveal some crucial characteristics and clues for the theoretical model of negative sprite.
44
張意佳. "A Study for the Application of the Characteristic of Ceramic and the Effect of Lighting on Lamps." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/81458410281074605298.
Повний текст джерелаАнотація:
碩士國立臺灣師範大學
設計研究所
89
At the present development of modern products were tend toward diversified, and it shows complete and comprehensive. So, the designers have to understand the whole factor before engaged in their working. The application and image of the materials are less investigated in the area of design. While create a production is not only need to conform with functional requirement, but also to pay attention to the psychological need. Therefore, it is very important to find out the communication model of psychology and know-how between designers with customers. The purpose of this study is using the ceramic characteristic and surface vision to apply to the lampshade. In the material application, china clay possess translucence, white, and elegance; and the same, argil possess plain, rough, and opaque. This study collocate these two kinds of clay together, and the product shows the particular contrast, which we can’t see in other materials. Furthermore, this characteristic let people cause emotional response to ceramics, and bring a new meaning to the area of ceramic design. In addition, by using the characteristic, it can construct a different image. When it was applied to lampshade design, it cause a unlike ambiance to other lamplight. After this study, we realize the ceramic characteristic and find an expressional form in china clay’s utilization. In addition to application of vision, I suggest the follow-up study when they are going to design ceramic lamplight, will focus on the surface, function, and lighting.
45
Hsu, Po-Yi, and 許柏毅. "Lightning Characteristics of 345kV Overhead Transmission System Under the Influences of Tower Grounding Resistances and Line Arresters." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/3mmp8v.
Повний текст джерелаАнотація:
碩士中原大學
電機工程研究所
93
In this thesis, the lightning characteristics of 345kV transmission system under the influences of tower grounding resistances and line arresters are studied. The ground potential rises(GPR) of tower due to ground fault can be reduced by lowering grounding resistances. However, it is necessary to study that whether the tower GPR can be reduced by lowering grounding resistances or not. Although, the line arresters are gradually used for lightning protection on transmission lines. Their availability are still under observation. Hence, this thesis is to study the lightning characteristics of transmission system with respect to different lightning striking locations by considering the affections of tower grounding resistances and line arresters, in which the tower GPR, lightning surge currents and voltage distributions on the overhead ground wires and three phase line conductors are analyzed for assessing the effetiveness of grounding resistances and line arresters. The existent lightning protection strategies and measures for overhead transmission lines in Taipower system are first described. Then, the circuit models based on electromagnetic-transient-program(EMTP) to represet Taipower 345kV overhead transmission system are constructed. The related moduals in EMTP are also illustrated. Finally, a practical case of double-circuit 345kV overhead transmission system with 20 towers and 7km length are simulated. The simulation results of various conditions are further analyzed and compared with each others for finding the relationships between lightning characteristics and tower grounding resistances and line arresters. The study results have shown that the effetiveness of tower grounding resistance on lightning is not same as it on ground fault, but the tower GPR can still be reduced with some degree by lowering grounding resistances and the lightning surge currents on overhead ground wires also reduced. The protection performances of line arresters are only evedently appered near by their locations. So, their installation are very important for protecting over all transmission system. This study provides some useful data for determing their installation.
46
Liang, Sing-Hua, and 梁興華. "Analysis of Lightning Surge Characteristics in the Primary Substations and Assessment of the Affections on the equipments." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/czpf8w.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
電機工程系優質電力產業研發專班
99
In this thesis, the lightning surge characteristics of primary substation with voltage level 161/69kV are studied. The work mainly aims to analyze lightning current and voltage on the primary and secondary side (161kV side and 69kV side) and grounding system with respect to various lightning points on 69kV and 161kV ground wires and buses. First of all, modeling of primary substation based on alternative transient program (ATP) is presented. Then, the lightning characteristics are analyzed by ATP simulations for lightning currents and voltages on the different locations of system and on grounding points of power transformers. For the simulation, different lightning points aforementioned, lightning arresters of power transformers, load levels and the grounding type of 161kV winding neutral points of main transformers are all taken into account. Finally, based on the ATP analysis results, the risks on the equipments such as buses, switches, breakers, power transformers and arresters in the substations due to lightning are evaluated. The study results have shown that lightning damages are very severe at secondary side of substation under heavy lightning even though it has lightning arresters, hence further lightning protection is required. The data presented in this thesis is valuable for further study on enhancing lightning protection for primary substation.
47
Chen, Cheng-Ting, and 陳政廷. "Lightning and Switching Surges Characteristics and Affection Assessment of Extra-High Voltage Substation in the Science Park." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/5bugq7.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
電機工程系研究所
100
The extra-high-voltage (EHV) substation(E/S) is erected continuously in each science park by Taiwan Power Company (TPC) for supplying power to substations and customers in the science park and nearby area. The lightning surges and switching surges of E/S are easily transferred to the downstream customers which are directly supplied by E/S. Thus, the impacts due to transferred surges will be more serious than that of other customers. The impacts will lead to damages on the insulation of distribution system and equipment and even threaten the safety of personnel. In thesis, the issue of surge damages of, the E/S in the science park and the E/S in the outside area of science Park (outside E/S) are studied. For both cases of customers directly supplied by E/S in the science park and indirectly supplied by outside E/S through distribution substation, the surge voltage and current are analyzed and compared, which include the analysis of lighting surges and switching surges transferred to the customers. Firstly, the circuit model of the system is constructed by the alternative transient program(ATP) of electromagnetic transient program(EMTP). Then, the surges at different locations due to lightning and switch operations are simulated and the characteristics of surge voltages and currents at customers are analyzed by ATP simulation. Based on the simulation results, the fault currents injected into grounding system at fault points are obtained. Finally, a software package for grounding system analysis, namely current distribution electromagnetic ground and soil structure analysis (CDEGS), is used to analyze the electromagnetic characteristics of ground grids of customer substations with respect to transient and steady states, which include the distribution of ground potential rise (GPR), potential on the ground surface, touch voltage, step voltage, conductor current and electromagnetic field (EMF) on the ground surface. According to the above analysis results, the risks of various surges are evaluated including the affections of lightning surges and switching surges on personnel, equipment and system.
48
Song, Zeqing. "A numerical model to evaluate characteristics of lightning breakdown channels in soils and current intercepted by buried cables." 2004. http://hdl.handle.net/1993/15733.
Повний текст джерела
49
Huang, Yiping. "Surface strength volt-time characteristics of processed pressboard under lightning, steep front and high frequency oscillatory impulse voltages." 1990. http://hdl.handle.net/1993/16995.
Повний текст джерела
50
Wu, Meng-Chang, and 吳孟昌. "Lightning Surge and Switching Surge Characteristics of Grounding System with Multi-gird in the Large High-Tech Factories." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/87260026030471237875.
Повний текст джерелаАнотація:
碩士中原大學
電機工程研究所
90
This study is to analyze the lightning and switching surges characteristics of grounding system of typical large integrated circuit (IC) manufacturing plants fed with 161kV power. The thesis analyzes lightning and switching surges characteristics of grounding system directly form the view point of electromagnetic principles, i.e. analyzes the electromagnetic characteristics of grounding system with respect to the lightning surges and switching surges. The analysis items included the ground surface potentials and electromagnetic fields. Based on the analysis results, the step and touch voltages related to human safety, and the transient ground potential rise (GPR´s) and ground potential difference (GPD´s) related to equipment protection are analyzed; from which, we can assess the damages of personnel and equipments on the grounding system. The analysis results have shown that the GPD´s produced by switching operation and lightning will threaten the safety of personnel, low voltage equipments and weak systems. For improving the protection performances of grounding system against the lightning and switching surges, the improving methods are proposed here. The improving methods will also contribute to upgrading the power quality.