Index to NASA Tech Briefs, January - June 1967

Technological innovations for January-June 1967, abstracts and subject inde

Outdoor Insulation and Gas Insulated Switchgears

This book focuses on theoretical and practical developments in the performance of high-voltage transmission line against atmospheric pollution and icing. Modifications using suitable fillers are also pinpointed to improve silicone rubber insulation materials. Very fast transient overvoltage (VFTO) mitigation techniques, along with some suggestions for reliable partial discharge measurements under DC voltage stresses inside gas-insulated switchgears, are addressed. The application of an inductor-based filter for the protective performance of surge arresters against indirect lightning strikes is also discussed

Effect of water on electrical properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as electrical insulating material

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Proceeding Of Mechanical Engineering Research Day 2016 (MERD’16)

This Open Access e-Proceeding contains a compilation of 105 selected papers from the Mechanical Engineering Research Day 2016 (MERD’16) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2016. The theme chosen for this event is ‘IDEA. INSPIRE. INNOVATE’. It was gratifying to all of us when the response for MERD’16 is overwhelming as the technical committees received more than 200 submissions from various areas of mechanical engineering. After a peer-review process, the editors have accepted 105 papers for the e-proceeding that cover 7 main themes. This open access e-Proceeding can be viewed or downloaded at www3.utem.edu.my/care/proceedings. We hope that these proceeding will serve as a valuable reference for researchers. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’16 are based on a combination of fundamental researches, advanced research methodologies and application technologies. As the editor-in-chief, we would like to express our gratitude to the editorial board and fellow review members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceeding of MERD’16

Emerging Innovative technologies and Materials in Hydropower Sector: A review

Various technological developments are now occurring in the hydropower sector. New technologies and practices are being developed to improve the hydropower system's adaptability and sustainability. To boost performance, durability, and flexibility, new novel materials that have been discovered through various research projects have also recently been introduced. In addition to improving efficiency, resistance, dependability, and durability, these cutting-edge materials have the potential to have a substantial impact on the hydropower sector's ability to manufacture, install, and transport equipment. Several novel materials are being introduced and numerous studies are continuing in the hydropower industry. Novel materials can be used for both new power plants and restoration projects. This study describes the most relevant novel materials used in various hydropower structure parts and components

Emerging Innovative technologies and Materials in Hydropower Sector: A review

Various technological developments are now occurring in the hydropower sector. New technologies and practices are being developed to improve the hydropower system's adaptability and sustainability. To boost performance, durability, and flexibility, new novel materials that have been discovered through various research projects have also recently been introduced. In addition to improving efficiency, resistance, dependability, and durability, these cutting-edge materials have the potential to have a substantial impact on the hydropower sector's ability to manufacture, install, and transport equipment. Several novel materials are being introduced and numerous studies are continuing in the hydropower industry. Novel materials can be used for both new power plants and restoration projects. This study describes the most relevant novel materials used in various hydropower structure parts and components

Index to 1983 NASA Tech Briefs, volume 8, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1983 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Study of oil/pressboard progressive creeping discharge under highly divergent electric field

As one of the most dangerous failure modes of transformers, the oil/pressboard progressive creeping discharge, as well as the corresponding insulation failure mechanisms, have thus far not been fully understood. The present thesis aims to gain a sound fundamental knowledge of the progressive creeping discharge, their influential factors, and the relevant failure mechanisms, as well as to contribute to an effective monitoring and diagnostic methodology. This study explored the progressive creeping discharges under highly divergent AC and DC voltages, respectively. The tests conditions were configured to investigate the impacts of critical influential factors, including ageing, voltage level, temperature, stress waveform, and oil flowing, on creeping discharges. The discharge processes were systematically evaluated using tools such as partial discharge, gas analysis, temperature monitoring, and finite-element simulation. Comparative analyses and theoretical examinations were made to the insulation faults as well as their correlated physicochemical phenomena. A conventional techniques-based monitoring framework was proposed for the dangerous creeping discharges, and the applicability of a new detection technique based on synchronous PD and dielectric measurements was tested as well. The characteristics of damage-free AC progressive creeping discharge, as well as the influences of pressboard ageing and field intensity, were investigated. It was found the progressive creeping discharge is a compound discharge that comprises mainly oil corona discharge and surface discharge. Pressboard ageing affected the discharge inception but had no influence on the interface breakdown strength. The damage-free discharge exhibited a constant PRPD pattern but had a diminishing PD intensity, where the pressboard ageing and voltage level jointly determine whether the discharges can be sustained or not. The damage-free discharge generated hydrogen principally and was located between D1/ D2 fault zones in the classical Duval’s Triangle. The insulation failures due to dangerous creeping discharges were comparatively studied. It was found the AC progressive creeping discharge could generate two faults to the pressboard, i.e., internal treeing (internal treeing) and surface tracking (surface tracking). The faults exhibited distinct electrical as well as physicochemical characteristics, and their occurrences were subject to pressboard ageing, voltage level, and pressboard density. A four-staged model was proposed to illustrate the development of internal treeing. The model highlighted the central role of the filament-like carbonization tracks in the pressboard interior, of which the onset and growth were theoretically expounded as well. A detection methodology was proposed for internal treeing, which was mainly based on continuous PD measurement, online temperature monitoring, and gas analysis. However, it was found still hard to detect a severe surface tracking fault due to the PD disappearance. The influences of temperature and voltage waveforms on AC progressive creeping discharge were studied. Temperature affected the short-time electric strength of either interface or oil gap and could form a synergistic effect with a strong field in exacerbating the dissipation factor of pressboard. Moreover, it was found temperature can determine the fault types and discharge severity under either constant or step-wise stress, whereas the stress waveform had an obvious effect on the fault type only at high temperatures. Depending on the test temperature and stress waveforms, the test specimens failed due to tracking-free interface flashover, surface tracking, and internal treeing, respectively. Their PD quantities were comparatively evaluated. Moreover, it was found the synchronous PD and dielectric measurement is highly indicative of the internal treeing process, and it exhibited both high detection sensitivity and discharge identification capability. The DC progressive creeping discharge was evaluated against temperatures and forced oil flows. Temperature affected the DC conductivity of both oil and pressboard, the resistivity ratio of pressboard to oil, and the oil/pressboard interface charge relaxation time. Accordingly, the interface field distributions were evaluated against temperatures using the finite-element method. Moreover, both oil flow speed and temperatures affected the short-time DC interface electric strength as well as the progressive creeping discharge. Two types of discharges were found under static oil condition. They exhibited distinct PD characteristics and showed different responses to temperature changes. They were presumably associated with discharges in oil and pressboard, respectively. Furthermore, it was found that forced oil flows can alter the behaviors of DC creeping discharges drastically and generated a peculiar PD type (Pulse Train). The occurrence of the pulse train was subject to applied voltage level, temperature, and oil flowing velocity. A theoretical model was proposed to elucidate the pulse train, in which the interactions between space charges from different sources were discussed against voltage levels, oil flows, and temperatures. The present thesis extends the knowledge of the oil/pressboard progressive creeping discharges. The research results are expected to serve as a base for future scientific studies and a piece of reference information for practical applications pertinent to progressive creeping discharges.Eine der gefährlichsten Fehlerarten in Transformatoren, die fortschreitende Kriechentladung in Öl/Feststoff Anordnungen sowie der dazugehörige Mechanismus des Isolationsfehlers sind noch nicht völlig geklärt. Die vorliegende Arbeit zielt auf die Erreichung einer soliden fundamentalen Kenntnis der fortschreitenden Kriechentladung, ihrer Einflussfaktoren und der entsprechenden Fehlermechanismen ab. Weiterhin soll sie einen Beitrag zur effektiven Überwachung und diagnostischen Methoden liefern. Die Untersuchungen beinhalten die fortschreitenden Kriechentladungen bei stark inhomogenen elektrischen Feldern unter Wechsel- und Gleichspannung. Die Versuchsbedingungen wurden so konfiguriert, dass die Wirkung der kritischen Einflussfaktoren auf die Kriechentladungen wie Alterung, Höhe der Spannung, Temperatur, Beanspruchungsform und Ölfluss, untersucht werden konnte. Die Entladungsvorgänge wurden systematisch ausgewertet unter Verwendung von Methoden wie Teilentladung, Gasanalyse, Temperaturerfassung und Simulation mit Finiten Elementen. Vergleichende Analysen und theoretische Prüfungen wurden im Hinblick auf Isolierungsfehler und der dazugehörigen physio-chemischen Erscheinungen durchgeführt. Ein auf konventioneller Technik basierendes Monitoring Konzept wurde für die gefährlichen Kriechentladungen vorgeschlagen und die Anwendung neuer Detektionstechniken basierend auf synchroner Teilentladungserfassung und dielektrischen Messungen geprüft. Die Eigenschaften von beschädigungsfreien fortschreitenden Kriechentladungen bei Wechsel-spannung und der Einfluss der Alterung des Pressspan sowie der Feldstärke wurden untersucht. Es wurde herausgefunden, dass die fortschreitende Kriechentladung eine zusammengesetzte Entladung ist, bestehend aus Korona-Entladungen in Öl und Oberflächenentladungen. Die Alterung von Pressspan beeinflusst den Einsatz der Entladung aber hat keinen Einfluss auf die Durchschlagsfestigkeit der Grenzfläche. Die beschädigungsfreie Entladung zeigt ein konstantes PRPD Muster aber mit abnehmender Teilentladungs-Aktivität, wobei die Alterung des Pressspans und die Spannungshöhe gemeinsam bestimmen, ob die die Entladungen unterbrochen werden oder nicht. Die beschädigungsfreie Entladung erzeugt grundsätzlich Wasserstoff und ist den Fehlerzonen D1/D2 des klassischen Duval Dreiecks zugeordnet. Die Fehler der Isolierung infolge der gefährlichen Kriechentladungen wurden vergleichend untersucht. Es wurde herausgefunden, dass die fortschreitende Kriechentladung bei Wechselspannung zwei Fehlerarten im Pressspan erzeugen kann, die schnelle Kriechwegbildung (internes Treeing) und die langsame Kriechwegbildung (Oberflächen Kriechweg). Die Fehler weisen deutlich elektrische als auch physio-chemische Eigenschaften auf und ihr Erscheinen war abhängig vom Alterungszustand des Pressspans, Spannungshöhe und Dichte des Pressspans. Ein vierstufiges Modell wurde vorgeschlagen um die Entwicklung der schnellen Kriechwegbildung darzustellen. Das Modell betont die zentrale Rolle der faserähnlichen karbonisierten Kriechwege im Inneren des Pressspans, wobei Einsatz und Wachstum theoretisch erklärt werden. Eine Erkennungsmethode für die Schnelle Kriechwegbildung wurde vorgeschlagen, die im Wesentlichen auf Teilentladungsmessungen, online Temperaturerfassung und Gas Analyse basiert. Es war dennoch schwierig eine langsame Kriechwegbildung zu erfassen, da Teilentladungen verschwanden. Die Einflüsse von Temperatur und Spannungsform auf fortschreitende Kriechwegentladungen wurden untersucht. Die Temperatur beeinflusste die kurzzeitige elektrische Feldstärke der Grenzschicht und der Ölstrecke und kann eine synergetische Auswirkung mit einem starken Feld auslösen, indem sich der Verlustfaktor des Pressspans erhöht. Es wurde weiterhin herausgefunden, dass die Temperatur die Fehlertypen und Entladungsstärke unter konstanter oder stufenweise Beanspruchung beeinflussen kann, wobei die Art der Beanspruchung einen klar erkennbaren Einfluss auf die Fehlerart nur bei hohen Temperaturen hat. Abhängig von der Prüftemperatur und der Beanspruchungsforme versagten die Prüflinge durch Grenzschichtüberschlag ohne Kriechwegspuren, langsame Kriechwegbildung und schnelle Kriechwegbildung. Ihre Teilentladungsgrößen wurden vergleichend ausgewertet. Darüber hinaus wurde herausgefunden, dass synchrone Teilentladungen und dielektrische Messungen eine gute Kennzeichnung für schnelle Kriechwegbildungsprozesse sind und es zeigt die Fähigkeit einer hohen Erkennungsempfindlichkeit und Entladungserkennung. Die fortschreitenden Kriechentladungen bei Gleichspannung wurden in Abhängigkeit der Temperatur und der Ölflussstärke ermittelt. Die Temperatur beeinflusst die Gleichspannungsleitfähigkeit von beiden, Öl und Pressspan, das Widerstandsverhältnis von Pressspan und Öl, und die Relaxationszeit der Grenzschichtladungen Öl/Pressspan. Dementsprechend wurde die Grenzschichtfeldverteilung in Abhängigkeit der Temperatur mit Hilfe der Finite-Elemente Methode ausgewertet. Außerdem beeinflussten die Geschwindigkeit des Ölflusses und die Temperaturen die kurzzeitige Grenzflächenfeldstärke bei Gleichspannung und fortschreitenden Kriechwegentladung. Zwei Arten von Entladungen wurde bei ruhendem Öl gefunden. Sie zeigen deutliche Teilentladungsmerkmale und unterschiedliches Verhalten bei Temperaturänderungen. Sie waren vermutlich verbunden mit Entladungen im Öl und Pressspan. Es wurde weiterhin herausgefunden, dass forcierte Ölströmung das Verhalten der Kriechentladungen bei Gleichspannung drastisch verändert und einen besonderen Typ von Teilentladungen erzeugt (Pulsfolge). Die Erscheinung dieser Pulsfolge war abhängig von der Höhe der angelegten Spannung, der Temperatur und der Geschwindigkeit des Ölflusses. Es wurde ein theoretisches Modell zur Verdeutlichung der Pulsfolge vorgeschlagen, bei dem die Wechselwirkungen zwischen Raumladungen von verschiedenen Quellen behandelt wurden in Abhängigkeit der Spannungshöhe, des Ölflusses und der Temperatur. Die vorliegende Arbeit erweitert die Kenntnis der fortschreitenden Kriechentladungen in der Anordnung Öl/Pressspan. Es wird erwartet, dass die Untersuchungsergebnisse als Basis für zukünftige wissenschaftliche Studien dienen und einen Beitrag mit hinweisenden Informationen für die praktische Anwendung zur Thematik fortschreitender Kriechentladungen liefern

Electrostatic discharge control for STDN stations

This manual defines the requirements and control methods necessary to control the effect of electrostatic discharges that damage or destroy electronic equipment components. Test procedures for measuring the effectiveness of the control are included