X-Rays from long laboratory sparks in air

This collective book provides a review of research concentrated on runaway electron beams and X-rays in an inhomogeneous electric field with different gases at increased pressure. Attention is also given to supershort avalanche electron beam (SAEB) in the optimal conditions. New experimental techniques and equipment, including those with picosecond time resolutions, were required for diagnostics of electrical and optical signals. The book consists of twenty-four chapters, some of which were written jointly by researchers of different teams. Some chapters consider the range of SAEB applications.Postprint (published version

An investigation into methods of modelling positive inhomogeneous-field breakdown and discharge process in SF6 with emphasis on the corona stabilisation phenomenon

dissertatic,11 submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Engineering, I.: Johannesburg, 1998Corona stabilisation is not a well understood phenomenon, consequently a rigorous theoretical description of how the merhanism operates does not exist. Furthermore, postulates on the prcJ'.tse physical processes that occur during corona stabilised breakdown are varied and conflicting. 1t was thus essential to develop a qualitative theory of how the mechanism operates around which a quantitative model could be constructed. To this aim, a detailed analysis of available modelling methods and empirical data from published works was carried out. This analysis together with additional finite elements modelling done as part of this work, leads to a proposed qualitative model which serves as a basis for a quantitative model developed to simulate corona stabilized breakdown from a fixed panicle defect. There is a favorable comparison between the predictions of the model and published measurements, thus imbuing optimism in the proposed method. The problem of measuring t: .;true charge deployed in a discharge is discussed and an experiment is designed to circumvent this problem

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

Evaluation of Geostationary Lightning Mapper performance using the Colombia-Lightning Mapping Array

The Geostationary Lightning Mapper (GLM) on the Geostationary Operational Environmental Satellites - R (GOES-R) series satellites is the first operational lightning mapper flown in a geostationary orbit, which provides continuous observations of lightning. In order to make use of these data for improving nowcasting of severe weather and for data assimilation, it is important to characterize and understand the detection capabilities of GLM. Observations from 3-dimensional VHF Colombia Lightning Mapping Arrays (COL-LMA) provide a valuable basis for evaluating the spatial accuracy and detection efficiencies of observations from the recently launched, optical-based Geosynchronous Lightning Mapper (GLM). This Bachelor Final Thesis results of comparing spatially and temporally the individual event (pixel) level for sets of individual discharges from the LMA and GLM observations. The focus is on a representative sample of case studies encompassing different forms of convective organization at different times of day and night. The detection efficiency of GLM relative to LMA will be characterized in terms of the flash number, size, power and height among others

Selected Papers from 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020)

The 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020) was held on 6–10 September 2020 in Beijing, China. The conference was organized by the Tsinghua University, China, and endorsed by the IEEE Dielectrics and Electrical Insulation Society. This conference has attracted a great deal of attention from researchers around the world in the field of high voltage engineering. The forum offered the opportunity to present the latest developments and different emerging challenges in high voltage engineering, including the topics of ultra-high voltage, smart grids, and insulating materials

The 1991 International Aerospace and Ground Conference on Lightning and Static Electricity, volume 1

The proceedings of the 1991 International Aerospace and Ground Conference on Lightning and Static Electricity are reported. Some of the topics covered include: lightning, lightning suppression, aerospace vehicles, aircraft safety, flight safety, aviation meteorology, thunderstorms, atmospheric electricity, warning systems, weather forecasting, electromagnetic coupling, electrical measurement, electrostatics, aircraft hazards, flight hazards, meteorological parameters, cloud (meteorology), ground effect, electric currents, lightning equipment, electric fields, measuring instruments, electrical grounding, and aircraft instruments

Rationales for the Lightning Flight-Commit Criteria

Since natural and artificially-initiated (or "triggered") lightning are demonstrated hazards to the launch of space vehicles, the American space program has responded by establishing a set of Lightning Flight Commit Criteria (LFCC), also known as Lightning Launch Commit Criteria (LLCC), and associated Definitions to mitigate the risk. The LLCC apply to all Federal Government ranges and similar LFCC have been adopted by the Federal Aviation Administration for application at state-operated and private spaceports. The LLCC and Definitions have been developed, reviewed, and approved over the years of the American space program, progressing from relatively simple rules in the mid-twentieth century (that were inadequate) to a complex suite for launch operations in the early 21st century. During this evolutionary process, a "Lightning Advisory Panel (LAP)" of top American scientists in the field of atmospheric electricity was established to guide it. Details of this process are provided in a companion document entitled "A History of the Lightning Launch Commit Criteria and the Lightning Advisory Panel for America s Space program" which is available as NASA Special Publication 2010-216283. As new knowledge and additional operational experience have been gained, the LFCC/LLCC have been updated to preserve or increase their safety and to increase launch availability. All launches of both manned and unmanned vehicles at all Federal Government ranges now use the same rules. This simplifies their application and minimizes the cost of the weather infrastructure to support them. Vehicle operators and Range safety personnel have requested that the LAP provide a detailed written rationale for each of the LFCC so that they may better understand and appreciate the scientific and operational justifications for them. This document provides the requested rationale