High Voltage

An analysis of the 87-year old science of electrogravitics (or electrogravity) necessarily includes an analysis of electrokinetics. Electrogravitics is most commonly associated with the 1928 British patent #300,311 of T. Townsend Brown, the 1952 Special Inquiry File #24-185 of the Office of Naval Research into the "Electro-Gravity Device of Townsend Brown" and two widely circulated 1956 Aviation Studies Ltd. Reports on "Electrogravitics Systems" and "The Gravitics Situation." By definition, electrogravitics historically has had a purported relationship to gravity or the object's mass, as well as the applied voltage. It also was tested recently by the Honda Corporation which published experimental results and proposed theory of a correlation between electricity and gravity. Electrokinetics, on the other hand, is more commonly associated with many patents of T. Townsend Brown as well as Agnew Bahnson, starting with the 1960 US patent #2,949,550 entitl...

surge arresters have strategic importance and a noble mission to provide guard for the power transformer (equipment of greater cost in a substation, which has many artisan-made parts in its construction, larger manufacturing times, larger difficulties to repairing, etc.), high-voltage circuit-breaker, the installations and their associated equipment in a substation. This paper presents a philosophy adopted for implementing renewal of surge arresters in an optimized way, looking for correspondences between power transformer failures and surge arresters, aiming at getting excellent results and economic attractiveness, as subsidies for asset and planning managers to take decisions on technological evolution.

In the present work we report on the electrochemical formation towards layers of multiscale MgO nanowhiskers by a two step approach. First, metallic magnesium was anodized under ''high-voltage"-conditions in chloride containing ethanol/water mixtures. This results within seconds in the formation of dense areas of magnesium hydroxide nanowhiskers on the surface. The individual as-grown whiskers have a needle tip shape, and a length depending on the growth time of up to 20 lm. The whiskers can be transformed to MgO by a thermal annealing process. To gain more insight into this very rapid growth process, the paper describes the influences of the key parameters of the anodization (pH, ion-concentration, electrolyte composition) and the effect of the thermal treatment on the morphology. All steps were characterized using SEM, EDX, XRD and XPS measurements.

Numerical computation of the electric field strength and ionic space charge density in electrode systems consisting of ionizing wire and non-ionizing cylinder, connected to the same DC high-voltage supply and facing a grounded plate, is a difficult problem, which is of interest to several electrostatic processes applications. In a previous study a simple numerical method has been proposed to calculate the spatial distributions of electric field and ionic space charge in a case of a continuum and uniform corona discharge originating at the surface of the wire. The aim of the present paper is to improve the physical model of the corona discharge in this particular electrode configuration, by assuming a more realistic law of charge injection on the wire circumference. The computations were carried out for an ionizing wire of radius r ¼ 0.1 mm, located at different distances h from a metallic tubular support of radius R ¼ 13.4 mm.The initial conditions of the corona discharge took into account the non-uniformity of the charge injection around the ionizing wire electrode. The computational results were compared with those obtained under the assumption of uniform corona discharge. The comparison pointed out that neither the non-uniformity of the electric field nor that of the charge injection can be neglected. They depend on the geometry of the electrode system and affect the distribution of the electric field and of the space charge density in the inter-electrode gap.

We report the fabrication and experimental characterization of a carbon nanotube (CNT)-based MEMS/NEMS electron impact gas ionizer with an integrated extractor gate for portable mass spectrometry. The ionizer achieves low-voltage ionization using sparse forests of plasma-enhanced chemical-vapordeposited CNTs as field emitters and a proximal extractor grid with apertures aligned to the CNT forests to facilitate electron transmission. The extractor gate is integrated to the ionizer using a high-voltage MEMS packaging technology based on Si springs defined by deep reactive ion etching. The ionizer also includes a high-aspect-ratio silicon structure (μfoam) that facilitates sparse CNT growth and also enables uniform current emission. The devices were tested as field emitters in high vacuum (10 −8 torr) and as electron impact ionizers using argon at pressures of up to 21 mtorr. The experimental data show that the MEMS extractor gate transmits up to 66% of the emitted current and that the ionizers are able to produce up to 0.139 mA of ion current with up to 19% ionization efficiency while consuming 0.39 W. [2009-0246] Index Terms-Carbon nanotubes (CNTs), deep reactive ion etching (DRIE), electron impact ionization, field emission, gas ionizer, portable mass spectrometry (MS), 3-D MEMS packaging. I. INTRODUCTION M ASS SPECTROMETERS are powerful analytical tools that are helpful to quantitatively determine the chemical composition of a sample. Unfortunately, conventional mass spectrometry (MS) hardware is bulky and power hungry, which limits the range of applications that the technology can satisfy. The development of gas chromatography and MS (GC/MS) systems that are small, light, mechanically and thermally robust, and low-powered would enable their portability and therefore would expand the applicability of MS techniques. Portable GC/MS systems, either as individual units or as part of massive networks, can be used in a wide range of in situ applications including geological survey, law enforcement, environ-Manuscript

The sheath thickness in plasma immersion ion implantation has been investigated in the presence of a transverse magnetic field. It has been found that the steady-state sheath thickness increases with increasing magnetic field strength. This result is in line with a simplified model of the sheath in which the steady-state sheath thickness is determined by the plasma density and ion velocity at the sheath edge. These results suggest that a magnetic field may be used to control the high-voltage sheath in plasma immersion ion implantation.

The measurements of electro-optical discharge characteristics and concentration of produced ozone were performed to evaluate the efficiency of ozone production in an AC surface dielectric barrier discharge (SDBD) in pure oxygen at atmospheric pressure. The discharge was driven in an amplitude-modulated regime with a driving AC frequency of 1 kHz, variable discharge duty cycle of 0.01–0.8 and oxygen flow rate of

Several electrostatic technologies, such as separation of granular mixtures, flocking, printing, or biological cell manipulation, are based on the accurate control of conductive particle motion in insulating gases or liquids by means of relatively high dc electric fields. This paper aimed at characterizing the behavior of such particles by numerical modeling of two aspects: 1) particle motion under the action of electric field forces and 2) insulation breakdown triggered by mobile particles. The equations of particle motion were written by taking into account both gravitational and drag forces, as well as the rebound at particle impact with the electrodes. If the particles move in ionized air, their charge varies in time. In that case, the equation of particle charge should be added to the mathematical model. The output data of the programs for numerical simulation of particle behavior are in good agreement with the available experimental results. Particle movements were shown to be influenced by the intensity of the electric field, by the density of the space charge, by size and mass density of the particles, as well as by their coefficient of restitution at impact with the electrodes. The conclusions regarding the behavior of conductive particles in insulating fluids are useful for the development of improved electrostatic separation technologies; they are of particular interest to all manufacturers of high-voltage equipment.

The development of pulsed discharges inside a stationary air bubble in water was observed using an intensified charge-coupled device camera with high-speed gate. The discharges were ignited from a tungsten wire inserted into a glass tube, which was immersed in the purified water. The pulsed high voltage was applied to the wire by an inductive energy storage system pulsed-power generator. The streamer discharge was propagated into the bubble from the wire tip with a propagation velocity of 0.5 mm/ns. A back discharge was observed due to a charge accumulation on the water surface and the glass tube.

Demand for low voltage cable diagnostics, arising from lifetime extension programs of power plants, grows recently. This paper reports on investigations of the authors with partial discharge testing of low voltage control, measurement and signal cables.

A theoretical study of possible neuromuscular incapacitation based on the application of high-intensity, ultrashort electric pulses is presented. The analysis is applied to a rat, but the approach is general and can be extended to any whole-animal and applies for any arbitrary pulse waveform. It is hypothesized that repeatable and reversible action potential blocks in nerves can be attained based on the electroporation mechanism. Our numerical studies are based on the Hodgkin-Huxley distributed circuit representation of nerves, and incorporate a nodal analysis for the time-dependent and volumetric perturbing potentials and internal electric fields in whole animals. The predictions are compared to actual 600-ns experimental reports on rats and shown to be in very good agreement. Effective strength-duration plots for neuromuscular incapacitation are also generated.

For Silicon Carbide (SiC) high-voltage rectifier diodes, contradictions appear when the most important parameter of the diodes, the minority carrier lifetime, is measured by different techniques. A qualitative analysis and a computer simulation have been carried out to clarify the origin of these contradictions. For 4H-SiC p + n diodes with 6-kV blocking capability, data on residual voltage drop at high current densities, switch-on time, reverse current recovery, and post-injection voltage decay are analyzed. It is shown that the whole set of experimental data can be explained by the existence of a thin ( 0 1 m) layer near the metallurgical boundary of the p + n junction with very small carrier lifetime that is essentially smaller than the carrier lifetime across the remaining part of the 50-m n-base. It is emphasized that the existence of such a layer allows, under certain conditions, the combination of a relatively low residual forward voltage drop and very fast reverse recovery. Approaches to minority carrier lifetime measurements are discussed.

The low-frequency ac-dc voltage transfer differences of thermal converters for higher voltages with planar multijunction thermal converters (PMJTCs) and series resistors have been determined by using only the assumption of a linear change of the low-frequency ac-dc current transfer difference of the PMJTC with input power. Uncertainties of less than 1 V/V are achieved up to 1000 V.

A new facility for 14C-AMS dating and for studies on cultural heritage by ion beam analysis has been put in operation at the University of Lecce, Lecce, Italy. The system is based on a 3 MV TandetronTM accelerator, manufactured by High Voltage Engineering Europa (HVEE). In the 14C-AMS system the three carbon isotopes are injected sequentially in the accelerator with cycle frequencies of up to 1 kHz. Performance tests have shown that the beams can be transported without any loss through the system. The 13C/12C precision of the system is 0.04% and no significant drift in the measured ratios is present.

This paper presents a driver for a HID lamp based on the application of a high frequency current square waveform through the lamp with the goal of avoiding acoustic resonances. The proposed ballast is fed from a 12V dc input voltage and is intended to be used in systems supplied from non-conventional sources, such as back-up batteries, photovoltaic generators and automotive applications. In order to initiate the discharge in the lamp an especially designed igniter supplied from the 12V dc voltage is used to apply high voltage ignition peaks to the lamp. Experimental results obtained from a laboratory prototype for a 70W Metal Halide lamp supplied at 30kHz are also shown to evaluate the possibilities of the proposed topology.

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This paper presents an integrated stimulator that can be embedded in implantable electrode books for interfacing with nerve roots at the cauda equina. The Active Book overcomes the limitation of conventional nerve root stimulators which can only support a small number of stimulating electrodes due to cable count restriction through the dura. Instead, a distributed stimulation system with many tripole electrodes can be configured using several Active Books which are addressed sequentially.

The RPC production sequence for the ATLAS experiment includes a specific test of current absorption at the operating point, which concerns the RPC ''gas volumes'', namely the bare detectors not yet assembled with the read-out panels and the mechanical support structures. The test, which is carried out at the production site, consists of two phases. The gas volumes are initially conditioned with pure argon, keeping the voltage constant just above the breakdown value of about 2 kV. The final test, performed after the volumes have undergone inner surface varnishing with linseed oil, is based on the measurement of the current-voltage characteristics with the binary operating gas, C 2 H 2 F 4 =i-C 4 H 10 ¼ 95=5. The results presented here concern 45% of the total foreseen production. r

This paper describes the characterisation of a set of 3 He proportional counters differing in gas composition and pressure. Each step of the signal generation in the detector is analysed. Optimal working conditions are defined in order to choose the high voltage to be applied. Dead time with short shaping time is measured in such optimal conditions. In addition, the overall neutron efficiency and the gamma sensitivity are reported. Such characterisation is required for a correct choice of the associated counting electronics and the applications of the counters.

This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar transistors (HBTs); the AlGaAs/GaAs HBT, the Si/SiGe HBT and the InGaAs/InP HBT. Our aim in this paper is to find the potentials and limitations of these devices and analyze them under common Figure of Merit (FOM) definitions as well as to make a meaningful comparison which is necessary for a technology choice especially in RF-circuit and system level applications such as power amplifier, low noise amplifier circuits and transceiver/receiver systems. Simulation of an HBT device with an HBT model instead of traditional BJT models is also presented for the AlGaAs/GaAs HBT. To the best of our knowledge, this work covers the most extensive FOM analysis for these devices such as I-V behavior, stability, power gain analysis, characteristic frequencies and minimum noise figure. DC and bias point simulations of the devices are performed using Agilent's ADS design tool and a comparison is given for a wide range of FOM specifications. Based on our literature survey and simulation results, we have concluded that GaAs based HBTs are suitable for high-power applications due to their high-breakdown voltages, SiGe based HBTs are promising for low noise applications due to their low noise figures and InP will be the choice if very high-data rates is of primary importance since InP based HBT transistors have superior material properties leading to Terahertz frequency operation.

The purpose of this paper is to study the effect of the high-voltage power supply waveform and the presence of a dielectric barrier on the collection of submicron particles in a wire-to-cylinder electrostatic precipitator. The experiments are carried out on two reactors (with or without dielectric barrier on the surface of the cylindrical collector electrode) with the same active section and volume. The results show that the highest collection efficiency is obtained with the negative dc corona. At equivalent electric power consumption, the Dielectric Barrier Discharge (DBD) is as effective as the positive dc corona and the ac corona. The efficiency can reach 99% with both studied reactors, if the necessary power is provided.

Silicon carbide (SiC) CMOS circuits have been developed recently to provide monolithic control for SiC MOS power switching devices. Although SiC CMOS is not well suited for high-end microprocessor applications, it must provide the necessary response time performance required for safe operation in high-voltage power switching applications. Despite previous developments in SiC CMOS process technology, which have enabled digital circuit operation using a 5 V power supply, circuit switching speeds were in the microsecond range. An obvious way to improve circuit performance is to scale device lateral and vertical dimensions. This paper describes recent progress in the development of a submicron, single metal, p-well CMOS process technology using 6H-SiC. Conventional NMOS transistors are fabricated with 0.5-mm (drawn) channel lengths and exhibit acceptable short-channel effects. Conventional PMOS transistors exhibit punchthrough at 0.8-mm channel lengths and require considerable channel engineering efforts which are also presented. Several digital logic gates and a ring oscillator have been fabricated with nanosecond gate switching performance. Performance limiting factors like parasitic series resistance is also investigated.

Ozone can cause many health problems, including exacerbation of asthma, throat irritation, cough, chest ache, shortness of breath, and respiratory infections. Air cleaners are one of the sources of indoor ozone, and thus the evaluation of ozone generated by air cleaners is desired significant issue. Most evaluation methods proposed are based on chamber tests. However, the adsorption and desorption of ozone on the wall of test chamber and the deposition of ozone resulted from the surface reaction can influence the evaluation results. In this study, we developed a mass balance model that took the adsorption, desorption and deposition of ozone into consideration to evaluate the effective ozone emission rates of six selected air cleaners. The experiments were conducted in a stainless steel chamber with a volume of 11.3 m 3 at 25 C and 60% relative humidity. The adsorption, desorption and deposition rate constants of ozone obtained by fitting the model to the experimental data were k a ¼ 0.149 AE 0.052 m h À1 , k d ¼ 0.013 AE 0.007 h À1 , and k r ¼ 0.050 AE 0.020 h À1 , respectively. The effective ozone emission rates of Air Cleaners No. 1, 2, and 3 ranged between 13,400e24,500 mg h À1 , 7190e10,400 mg h À1 , and 4880e6560 mg h À1 , respectively, which were more stable than those of No.4, 5, and 6. The effective ozone emission rates of Air Cleaners No. 4, 5, and 6 increased with the time of operation which might be relevant to the decrease of ozone removal by the "aging" filter installed in these cleaners. The removal of toluene and formaldehyde by these six air cleaners were also evaluated and the clean air delivery rates (CADRs) of these two pollutants ranged from non-detectable to 0.42 AE 0.08 m 3 h À1 , and from non-detectable to 0.75 AE 0.07 m 3 h À1 , respectively. The CADRs showed an insignificant relationship with the effective ozone emission rates. Thus, the removal of toluene and formaldehyde might be resulted from the adsorption on the filters and the decomposition by the high-voltage electric discharge or the ionization that generated ozone.

This paper is addressed to the design and optimisation of junction termination extension and floating guard rings edge termination structures to integrate 6.5 kV IGBT devices. The developed edge termination structures are extensively analysed through numerical simulations, and experimental data on fabricated diode structures are correlated with simulation results. q

The influence of the number and position of air gaps on the 50% ac withstand voltage, V 50 , of a short string of 5 IEEE standard insulator units covered with ice was experimentally investigated and numerically simulated. The results show that the V 50 is affected by the number and position of the air gaps. The results also show that the presence of a partial arc along the air gap close to the high voltage (HV) electrode leads to a redistribution of the voltage along the ice-covered insulator. Based on the obtained results, suggestions for improving the performance of line insulators under icing conditions were proposed.

The charge on ambient atmospheric particles is an important parameter in the investigation of particle dynamics. Yet, there is only limited knowledge available on it, mainly due to the lack of instrumentation for its direct measurement. The aim of this study was to explore the application and suitability of the Aerosol Electrometer (AE) TSI Model 3068 as a direct instrument for measuring ambient particle charge concentration, thereby extending its use beyond the current applications. Through a set of experimental investigations the AE was applied to measure net concentration of charged particles in different environments. Results of the study showed the instrument is mostly suitable for outdoor field measurement, when particle charge concentrations are elevated, such as in the vicinity of strong ion emitting sources (high voltage powerlines, electricity substations, etc); and under conditions of air relative humidity of below 60%. Operating the instrument above this humidity value would require the use of a dehumidifier. 74% (R 2) statistical correlation (P<0.05) was obtained between the readings of the AE and the Air Ion Counter, when both instruments were used to simultaneously sample ambient air.

Surface flashover in compressed-gas insulated systems is a much studied, but poorly explained phenomenon. In this paper we review the literature of surface flashover with primary emphasis on the understanding of physical processes leading to discharge initiation and insulator flashover under high voltage excitation. The flashover models presently in vogue will first be discussed, followed by the results of some recent experiments which are likely to have an impact on further modeling. Included in this context are phenomena such as ionization, surface charging, partial discharges, optical activity, and gas/dielectric interactions. Finally, the influence of system parameters such as insulator size, shape, surface condition, triple junction geometry, voltage waveform, gas formulation and particle contamination are discussed with regard to their effect on the flashover characteristics. Mechanisms are suggested in an effort to provide a physical explanation for the observed phenomena. Although the physics of the discharge initiation and propagation processes are presently not well understood, and the present models only account for a few of the mechanisms known to be important in the discharge development, all the work points to an interaction between the spacer and the various electron/photon processes in the surrounding gas volume. This interaction has not been accounted for in the discharge models proposed to date. Further modeling work should incorporate these interactions and the intrinsic properties of the dielectric which are related to these interactions. More basic research is suggested to provide a better understanding of the physics of the discharge initiation and breakdown phenomena. '0) I-9-7 / 836/ 1 CJ'X C-i-O2 .' 7$c.I 0 2-1 96 iTEEE TEEE Tansctin~s E1m ti a1Iz-ti EVlTl-KM No.- .-tober I 9Rbs o few guidelines existed for designing a better spacer. Clearly this indicates a strong need to investigate the fundamental processes relevant to the flashover mechanism. A more recent review by Laghari and Quereshi [5] was also of an applied nature, perhaps to an even greater degree. This review detailed the flashover characteristics of spacers used in compressed-gas insulation transmission (CGIT) systems, with particular emphasis on systems containing conducting particulate contamination. The review covered most of the items of interest to CGIT systemse.g. gas insulation, spacer materials, spacer geometries, arc resistance, partial discharge behavior, waveform of voltage application, shielded electrodes, inserts, and contamination due to conducting particles. In contrast to these earlier reviews, the review presented here is of a more fundamental nature. In this review there will be a concentration on the physical processes which lead to and culminate in breakdown of insulator-bridged gas insulated systems. As there has not been a great amount of work of a fundamental nature reported in the literature, it will be necessary to rely, to some extent, on practical observations in order to extract data with regard to the physical processes. For this reason, papers included in this review are as likely to deal with practical observations as are to deal with-fundamental measurements. Topics such as flashover modeling, measurements of surface charge densities, partial discharge characteristics, and optical activity will be discussed along with the more practical observations of insulator shape effects, surface condition, triple junction geometry, etc.

The development of microrobots is very important in fields where sub-micrometre precision is required. An integrated driving solution based on a commercial BCD (bipolar, CMOS, DMOS) technology is proposed to implement proper drivers for microrobots formed by smart piezoactuator units (SPU). The high voltage signals that demand these actuators are performed by a driver based on a full custom design of a high voltage operational amplifier connected in the inverter configuration. They are able to supply a 50V sinusoidal waveform at frequencies ranging about 10 kHz with the distortion levels appropriate to the application.

This paper presents the design, fabrication, and comparison of different planar edge termination techniques on high-voltage 4H-SiC PiN diodes, including single-and double-junction termination extensions (JTE), floating guard rings, and a novel termination structure, the so-called "floating guard rings-assisted JTE." The influence of the anode metal edge location over different periphery regions on the breakdown voltage is also discussed, as well as the effect of a field plate and the passivation layer on the reverse characteristics. The terminations were studied by way of two-dimensional numerical device simulations and they are confirmed by fabricating and measuring 1.7-kV 4H-SiC aluminum implanted PiN diodes. It is shown that the novel termination structure provides the best results achieving the highest breakdown voltages with good production yield. The fabricated diodes also exhibited excellent forward current characteristics with a low on-state voltage drop of 3.0 V at 100 A/cm 2 , thanks to the low specific contact resistivity achieved ( = 1 10 5 cm 2 ) after the high-temperature treatment of the anode contact. High-temperature reverse current-voltage measurements were also carried out and are presented and discussed.

Power transformers have been in service for many years under different conditions. Statistical studies have shown that failures of bushings are one of the main causes for long duration outages of transformers. The development of an instrument for supervising the conditions of transformers bushings is, therefore, of special interest. In this contribution two methods are introduced for monitoring of bushings. In the first method, using summation voltage of transformer bushings from bushing taps with and without neutral point voltage are considered. In the second method a new sensor is used which can give voltage signal as a signal reference from the high voltage conductor in each bushing. Comparing the signal reference with using tap voltage signal can evaluate the condition of transformer bushing. In addition a software for monitoring and diagnostic of transformer bushing is presented.

The company JEMA has delivered to the Joint European Torus (JET facility in Culham) two high voltage switching mode power supplies (HVSMPS) each rated 130 kVdc and 130 A. One HVSMPS feeds the grids of two PINI loads. This paper describes the main control issues and the algorithms developed for the project. The most demanding requirements from the control point of view is an absolute accuracy of ±1300 V and the possibility of performing up to 255 re-applications of the high voltage during a 20 s pulse. Keeping the output voltage ripple to the specified tolerance has been a major achievement of the control system. Since the output stage is formed of several modules (120) connected in series, their stray capacitance to ground significantly influences the individual contribution of each single module to the global output voltage. Two complementary techniques have been used to balance the effects of the stray capacities. The fast re-applications requirement has a significant impact on the intermediate dc link. This section is composed of a capacity of 0.83 F, which feeds the 120 invertor modules. The dc link is fed by a 12 pulse SCR rectifier, whose matching transformers are connected to the 36 kV grid. Every re-application and every voltage shutdown supposes a quasi-instantaneous power step of 17 MW. Fast open loop algorithms have been implemented in order to keep the dc link voltage within acceptable margins. Moreover, the HVSMPS output characteristics have to be maintained during the rapid and important voltage fluctuations of the 36 kV mains (28-37 kV). The general control system is based on a Simatic S7 PLC, and a SCADA user interface. Up to 1000 signals are acquired. The control system has shown to be also a useful tool to allow for a rapid and accurate identification of faults and their origin.

Multilevel inverters have been widely accepted for high-power high-voltage applications. Their performance is highly superior to that of conventional two-level inverters due to reduced harmonic distortion, lower electromagnetic interference, and higher dc link voltages. However, it has some disadvantages such as increased number of components, complex pulsewidth modulation control method, and voltage-balancing problem. In this paper, a new topology with a reversing-voltage component is proposed to improve the multilevel performance by compensating the disadvantages mentioned. This topology requires fewer components compared to existing inverters (particularly in higher levels) and requires fewer carrier signals and gate drives. Therefore, the overall cost and complexity are greatly reduced particularly for higher output voltage levels. Finally, a prototype of the seven-level proposed topology is built and tested to show the performance of the inverter by experimental results.

ZnO-based varistors are frequently used for electronic circuits overvoltage protection. Such material requires sintering at temperatures of 1150 o C-1300 o C. Lowering it to the typical range 850 o C-950 o C used in thick -film and LTCC technology is desirable. ZnO-based paste was prepared and exploited for varistors fabrication on alumina and LTCC substrate. Different component topologies, materials for electrodes and firing profiles were used. I-V characteristics of varistors as well as long term stability and durability to high voltage pulses were investigated. Satisfactory results were achieved.

Utilizing the core technologies of emerging microrobotic structures, the rapid design and prototyping of a passive micro air vehicle with the final goal of locating an audio source while avoiding hazardous obstacles is presented. The airfoil and control surfaces are optimized empirically to maximize lift and maneuverability while minimizing drag. Bimorph piezoelectric bending cantilevers actuate the control surfaces. Since such actuators require high voltages, an efficient boost circuit is presented along with appropriate high voltage electronics. To locate audio sources, a pair of acoustic sensors is designed and prototyped using a phase detection algorithm while a custom optic flow sensor is developed to avoid obstacles and give estimates of object distances and velocities. Finally, each subsystem is demonstrated and the complete glider is integrated to demonstrate initial open loop control performance.

Converting existing AC lines to DC for increasing power transmission has been an interesting topic for scientists, such applications could be managed by conventional converters. Converting AC lines to DC upgrades the power capacity of existing lines up to square root of two. In this paper, a modified converter that would use all three existing AC lines at the same

This paper aims to highlight the observations made on surge performance of a power transformer. The impulse test on power transformers simulates the conditions that exist in service when a transformer is subjected to an incoming high voltage surge due to lightning or other disturbances on the associated transmission line. A simulated non-linear transformer model helps to analyze the surge response under varying impulse waveforms accurately and so surge modeling of the transformer using MATLAB SIMULINK has been done. For a range of applied waves (both standard and non-standard) and different winding connections, comparison of the insulation characteristics under non-standard lightning impulse voltage waveforms which represent actual surge waveforms encountered in the field and the characteristics under the standard lightning impulse waveform quantitatively can be made. An investigation on the transformer behavior when subjected to standard and non standard impulse waves is done in this paper. The maximum voltage to ground and maximum voltage across the coils along with the time of their occurrences against different coils for 0% tapping and 10% tapping respectively is recorded and analyzed.

Testing plays an important role in controlling and ensuring required quality and reliability of manifactured integrated circuits (ICs) before supplying them to final users. Several types of testing are performed at different stages of the IC manufacturing process. One of them is so-called burn-in testing (i.e. accelerated testing performed under elevated temperature

This article proposes and implements actions for guarantee of metrological reliability and safe conformity assessment of tested equipments when using standard capacitors. It is presented: a review on standard capacitor typical behavior and the description of an experiment for reduction the contribution on uncertainty.

This research aims to evaluate the trends in the publication of papers on issues related to power circuit breakers, aimed at the technologies implemented, as well as those countries with higher level of publications, making a comparison between authors, research institutes, and a description of the last 10 years with more publications. All the information found in this report is compiled in bibliographic databases such as books of substation designs and research papers with a focus on electrical protection equipment and emphasis on high voltage switching devices. A technology research is conducted over the last ten years to analyze the state of the art of high voltage operating elements with respect to new technologies.

Diffuse glow discharges were produced in low temperature (<2000 K) atmospheric pressure air and nitrogen plasmas with electron number densities in excess of 10 12 cm -3 , more than six orders of magnitude higher than in thermally heated air at 2000 K. The measured discharge characteristics compare well with the predictions of a two-temperature kinetic model. Experimental and modeling results show that the steady-state electron number density exhibits an S-shaped dependence on the electron temperature, a behavior resulting from competition between ionization and charge-transfer reactions. Non-Maxwellian effects are shown to be unimportant for the prediction of steady-state electron number densities. The power requirements of DC discharges at atmospheric pressure can be reduced by several orders of magnitude using short repetitive high-voltage pulses. Between consecutive pulses, the plasma is sustained by the finite rate of electron recombination. Repetitive discharges with a 100-kHz, 12-kV, 10-ns pulse generator were demonstrated to produce over 10 12 electrons/cm 3 with an average power of 12 W/cm 3 , 250 times smaller than a DC discharge at 10 12 cm -3 .