Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Smart Grid Technologies in Europe: An Overview

The old electricity network infrastructure has proven to be inadequate, with respect to modern challenges such as alternative energy sources, electricity demand and energy saving policies. Moreover, Information and Communication Technologies (ICT) seem to have reached an adequate level of reliability and flexibility in order to support a new concept of electricity network—the smart grid. In this work, we will analyse the state-of-the-art of smart grids, in their technical, management, security, and optimization aspects. We will also provide a brief overview of the regulatory aspects involved in the development of a smart grid, mainly from the viewpoint of the European Unio

Application of a simplified thermal-electric model of a sodium-nickel chloride battery energy storage system to a real case residential prosumer

Recently, power system customers have changed the way they interact with public networks, playing a more and more active role. End-users first installed local small-size generating units, and now they are being equipped with storage devices to increase the self-consumption rate. By suitably managing local resources, the provision of ancillary services and aggregations among several end-users are expected evolutions in the near future. In the upcoming market of household-sized storage devices, sodium-nickel chloride technology seems to be an interesting alternative to lead-acid and lithium-ion batteries. To accurately investigate the operation of the NaNiCl2 battery system at the residential level, a suitable thermoelectric model has been developed by the authors, starting from the results of laboratory tests. The behavior of the battery internal temperature has been characterized. Then, the designed model has been used to evaluate the economic profitability in installing a storage system in the case that end-users are already equipped with a photovoltaic unit. To obtain realistic results, real field measurements of customer consumption and solar radiation have been considered. A concrete interest in adopting the sodium-nickel chloride technology at the residential level is confirmed, taking into account the achievable benefits in terms of economic income, back-up supply, and increased indifference to the evolution of the electricity market

Electronic/electric technology benefits study

The benefits and payoffs of advanced electronic/electric technologies were investigated for three types of aircraft. The technologies, evaluated in each of the three airplanes, included advanced flight controls, advanced secondary power, advanced avionic complements, new cockpit displays, and advanced air traffic control techniques. For the advanced flight controls, the near term considered relaxed static stability (RSS) with mechanical backup. The far term considered an advanced fly by wire system for a longitudinally unstable airplane. In the case of the secondary power systems, trades were made in two steps: in the near term, engine bleed was eliminated; in the far term bleed air, air plus hydraulics were eliminated. Using three commercial aircraft, in the 150, 350, and 700 passenger range, the technology value and pay-offs were quantified, with emphasis on the fiscal benefits. Weight reductions deriving from fuel saving and other system improvements were identified and the weight savings were cycled for their impact on TOGW (takeoff gross weight) and upon the performance of the airframes/engines. Maintenance, reliability, and logistic support were the other criteria

Interdependent energy relationships between buildings at the street scale

Oppgaven tar for seg en analyse av etterforsyning av flytende oksygen(LOX) til C-130J i internasjonale operasjoner og er gjennomført som en case-studie av NORTAD2. Hensikten med undersøkelsen er å anbefale det etterforsyningskonseptet som vil sikre tilgang på LOX til NORTAD3 og som i fremtiden vil kunne benyttes i liknende operasjonsområder. Studien drøfter tre konseptuelt ulike løsninger for etterforsyning: obtain in the battlefield, ship to the forces og carry with the troops, avgrenset til responssyklusen fra siste leverandør til sluttbruker. Først gjøres det en analyse av dagens løsning obtain in the battlefield med lokal leveranse fra leverandøren Air Liquid. Analysen er gjennomført med utgangspunkt i teori fra fagområdet logistikk. I teorien identifiseres det tre hovedutfordringer: usikkerhet knyttet til kvalitet, ledetid og sikkerhet, spesialtilpasning av responssyklusen for et heterogent produkt og organisering av kjeden. Drøftingen tar utgangspunkt i de identifiserte problemene og søker å finne løsninger som kan redusere disse. Den første løsningen som drøftes er ship to the forces ved etterforsyning fra Las Palmas eller nærmeste tilgjengelige flyplass med godkjent LOX. Løsningen vil redusere usikkerhet knyttet til de nevnte faktorene, men imidlertid forlenge ledetiden til to dager. Samtidig reduseres behovet for LOX-spesifikt materiell og personell, og således reduserer ressursbruken. I tillegg vil arbeidet i forkant av bidraget minskes, men tvert imot øke det administrative arbeidet underveis. Løsningen vil by på en prioritering av operativ tilgjengelighet på flymaskinen og redusert usikkerhet. Løsningen anbefales ikke som det primære etterforsyningskonseptet da operativ tilgjengelighet vil være en prioritet. Videre drøftes en rotasjonsordning som et carry with the troops-konsept. Løsningen vil kunne redusere ledetiden ved rotasjon i Mali, men redusere Forsvarets totale fleksibilitet med tanke på transportflykapasitet. Her vil også behov for LOX-spesifikt materiell og personell reduseres. På den andre siden identifiseres det at løsningen vil skape god fleksibilitet for bidraget i forbindelse med LOG-flights og kan således styrke bidraget. Det antas at løsningens totale ressursbruk vil overstige dagens, men det anbefales å gjøre en grundig kost-nytte analyse av denne løsningen. Avslutningsvis drøftes forbedringer ved nåværende løsning. Her foreslås det å sikre operativ tilgjengelighet på lagertanken med en vedlikeholdsplan og utdanning på denne. Samtidig anbefales det investering i egen transportkapasitet for frakt av LOX for å redusere usikkerheten knyttet til leveransen og sikkerhet. Sist bør forståelsen for LOX økes i hele organisasjonen gjennom utdanning slik at å sikre etterforsyning prioriteres. Oppgavens konklusjon og anbefaling er å videreføre dagens løsning med noen utbedringer. Løsning ship to the forces anbefales som plan B. Samtidig bør det gjennomføres en kost-nytte analyse av carry with the troops

Review of trends and targets of complex systems for power system optimization

Optimization systems (OSs) allow operators of electrical power systems (PS) to optimally operate PSs and to also create optimal PS development plans. The inclusion of OSs in the PS is a big trend nowadays, and the demand for PS optimization tools and PS-OSs experts is growing. The aim of this review is to define the current dynamics and trends in PS optimization research and to present several papers that clearly and comprehensively describe PS OSs with characteristics corresponding to the identified current main trends in this research area. The current dynamics and trends of the research area were defined on the basis of the results of an analysis of the database of 255 PS-OS-presenting papers published from December 2015 to July 2019. Eleven main characteristics of the current PS OSs were identified. The results of the statistical analyses give four characteristics of PS OSs which are currently the most frequently presented in research papers: OSs for minimizing the price of electricity/OSs reducing PS operation costs, OSs for optimizing the operation of renewable energy sources, OSs for regulating the power consumption during the optimization process, and OSs for regulating the energy storage systems operation during the optimization process. Finally, individual identified characteristics of the current PS OSs are briefly described. In the analysis, all PS OSs presented in the observed time period were analyzed regardless of the part of the PS for which the operation was optimized by the PS OS, the voltage level of the optimized PS part, or the optimization goal of the PS OS.Web of Science135art. no. 107

Aeronautical Engineering: A special bibliography with indexes, supplement 55

This bibliography lists 260 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1975