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Approved for public release; distribution is unlimited / A five microsecond, 15 joule, pulsed C0₂ Laser was used to irradiate polished 2024 aluminum targets. The target voltage response (TVR) was measured with respect to the incident laser radiation and showed a pulse width on the order of 30 nanoseconds. The voltage was measured at values from 22 to 140 volts with resistances varying from one ohm to two mega-ohms. The TVR was correlated to the emission and blow-off of electrons from the target surface and the possible ignition of a Laser Supported Detonation wave. The TVR, laser pulse, and flash associated with target surface breakdown were time correlated and shown to happen within the first 170 nanoseconds of the five microsecond laser pulse. Currents up to 500 amps were observed when the resistance to ground was reduced to less than 1 ohm. Also, the magnitude of the TVR was shown to be a function of background gas pressure. / http://archive.org/details/targetvoltageres00hark / Lieutenant, United States Navy

Reliability is one of the important issues of recent microprocessor design. Processors must provide correct behavior as users expect, and must not fail at any time. However, unreliable operation can be caused by excessive supply voltage fluctuations due to an inductive part in a microprocessor power distribution network. This voltage fluctuation issue is referred to as inductive or di/dt noise, and requires thorough analysis and sophisticated design solutions. This dissertation proposes an automated stressmark generation framework to characterize di/dt noise effect, and suggests a practical solution for management of di/dt effects while achieving performance and energy goals. First, the di/dt noise issue is analyzed from theory to a practical view. Inductance is a parasitic part in power distribution network for microprocessor, and its characteristics such as resonant frequencies are reviewed. Then, it is shown that supply voltage fluctuation from resonant behavior is much harmful than single event voltage fluctuations. Voltage fluctuations caused by standard benchmarks such as SPEC CPU2006, PARSEC, Linpack, etc. are studied. Next, an AUtomated DI/dT stressmark generation framework, referred to as AUDIT, is proposed to identify maximum voltage droop in a microprocessor power distribution network. The di/dt stressmark generated from AUDIT framework is an instruction sequence, which draws periodic high and low current pulses that maximize voltage fluctuations including voltage droops. AUDIT uses a Genetic Algorithm in scheduling and optimizing candidate instruction sequences to create a maximum voltage droop. In addition, AUDIT provides with both simulation and hardware measurement methods for finding maximum voltage droops in different design and verification stages of a processor. Failure points in hardware due to voltage droops are analyzed. Finally, a hardware technique, floating-point (FP) issue throttling, is examined, which provides a reduction in worst case voltage droop. This dissertation shows the impact of floating point throttling on voltage droop, and translates this reduction in voltage droop to an increase in operating frequency because additional guardband is no longer required to guard against droops resulting from heavy floating point usage. This dissertation presents two techniques to dynamically determine when to tradeoff FP throughput for reduced voltage margin and increased frequency. These techniques can work in software level without any modification of existing hardware. / text

Elkvalitet beror på flera olika faktorer, exempelvis kortvarig spänningshöjning, kortvarig spänningssänkning, snabba spänningsvariationer (flimmer), spänningssprång, transienter, övertoner eller spänningsosymmetri. Den vanligaste åtgärden för att förbättra elkvaliteten i ett industrinät med ljusbågsugn och höga nivåer av snabba spänningsvariationer är att använda sig av reaktiv effektkompensering.  Denna studie undersöker snabba spänningsvariationers eventuella påverkan på elektrisk utrustning, både gällande användning och livslängd. Vidare undersöks även elkvaliteten i Sandviks industrinät där elektrisk utrustning upplevs ha blivit defekt tidigt under dess livslängd. Detta för att finna åtgärder som kan förbättra elkvaliteten för industrinätet, där en ljusbågsugn används i produktionen. I studien har mätdata gällande elkvalitet från Sandvik jämförts med mätdata från andra industrier vilket sedan analyserat utifrån gällande elkvalitetsnormer. Data om vilken typ av utrustning som kan ha påverkats och information om hur elnätsföretag upplever industriers påverkan på elkvalitet har samlats in genom intervjuer med personal på Sandvik och Vattenfall. Även tidigare forskning behandlas i denna studie. Resultatet visar att Sandviks elkvalitet påverkas av när ljusbågsugnen körs. Flimmernivån är den elkvalitetsstörning som återkommande överstiger normen vid anslutningspunkten av utrustning som tidigt blivit defekt. Tidigare forskning visar att användandet av utrustning kan påverkas av snabba spänningsvariationer till exempel i form av mindre hastighetsförändringar i motorer. I jämförelsen mellan Sandvik och de andra industriernas mätdata framkommer bland annat att höga flimmernivåer är vanligt förekommande i industrinät med ljusbågsugn. För att åtgärda Sandviks flimmernivåer och förbättra deras elkvalitet kan en reaktiv effektkompensering i form av en STATCOM installeras. Det finns inte forskning i tillräcklig stor grad för att kunna dra säkra slutsatser gällande hur snabba spänningsvariationer påverkar elektrisk utrustnings livslängd. Det finns dock forskning som indikerar att så är fallet. Denna studies insamlade data leder inte heller till några säkra slutsatser gällande detta men tydliggör att nuvarande testprocedurer om utrustnings immunitet mot snabba spänningsvariationer inte går att jämföra med de verkliga förhållandena i ett industrinät. Slutsatsen är även att fler studier i ämnet krävs. / Power quality depends on several different factors, such as voltage sags, voltage dips, voltage fluctuation (flicker), rapid voltage changes, transients, harmonics or voltage asymmetry. To improve the power quality in an industrial network one common mitigation is reactive power compensation.     This study examines the possible effects of voltage fluctuations on electronic equipment, both in terms of use and service life. Furthermore, Sandvik's power quality in their industrial network is also examined, where electronic equipment is perceived to have become defective early in its service life. To improve the power quality the goal is to find suitable mitigation for the arc furnace in the industrial network. In this study, the power quality at Sandvik was compared with the power quality from similar industries and analyzed based on current power quality standards. Through interviews with staff at Sandvik and Vattenfall data was provided regarding which type of equipment that may have been affected and information on how electricity network companies experience the impact from industries on power quality. Previous research is also covered in this study. The result shows that the power quality at Sandvik is affected when the arc furnace is active. The flicker level is the power quality disturbance that repeatedly exceeds the norm at the connection point of equipment that has become defective at an early stage. Previous research shows that the use of equipment can be affected by voltage fluctuations, for example in the form of minor speed changes in motors. The comparison between Sandvik and the similar industries reveals that industrials networks with an arc furnace often is affected by high flicker levels. By installing a reactive power compensator, in form of a STATCOM, the high flicker level of Sandvik’s industrial network can be mitigated. There is not enough research to be able to draw definite conclusions if voltage fluctuation affects the lifespan of electronic equipment. However, there is research that indicates that this is the case. The data collected in this study also do not lead to any definite conclusions regarding this but clarifies that current test procedures on equipment immunity to voltage fluctuations cannot be compared with the actual conditions in an industrial network. The conclusion is also that more studies on the subject are required.

For planning issues, it is useful to know the upper limit for photovoltaics (PV) in the electrical grid with current design and operation (defined as hosting capacity) and how this limit can be increased. Future costs for grid reinforcement can be avoided if measures are taken to implement smart grid technology in the distribution grid. The aim of this project is to identify challenges in Swedish electricity distribution grids with a high penetration of local generation of electricity from PV. The aim is also to help Swedish Distribution System Operators (DSOs) to better understand hosting capacity issues, and to see which room for PV integration there is before there is need for actions to maintain power quality. Three distribution grids are modelled and simulated in Matlab: Rural area, Residential area and City (Stockholm Royal Seaport). Since the project is a cooperation between Uppsala University and Fortum, three different representative grids from Fortum’s grid software ”Power Grid” have been used as input to a flexible simulation program developed at Uppsala University. The simulation includes Newton-Raphson power-flow computing but has also been improved with a model of the temperature dependency of the resistance. The results show that there is room for a lot of PV systems in the Swedish grids. When using voltage rise above 1.1 p.u. voltage as limitation, the hosting capacity 60% PV electricity generation as a fraction of the yearly load were determined for the rural grid and the suburban grid. For the city grid, which is very robust, the hosting capacity 325% was determined. When using overload as limitation, the hosting capacities 70%, 20% and 25%, were determined for the same grids.