3,150 research outputs found
STUDI DI TRANSITORI ELETTROMECCANICI ED ELETTROMAGNETICI PER LINEE MISTE DI TRASMISSIONE AEREOCAVO
No full textSynchronizing Interactions Between Different Types of Grid-Forming Converters in Smart Grids
No full textThe work investigates the transient synchronizing interactions between different types of grid-forming controls. Two well-known grid-forming schemes are implemented and considered for analysis: a droop-based control and a swing-based control. The two controls are examined for a temporary loss of synchronism. The analysis is performed considering two different conditions for the grid interconnecting the converters: a resistive-inductive grid and a mainly inductive grid. The first case corresponds to actual conditions in low and medium voltage applications. The second case is realized with the implementation of a virtual reactance in the grid-forming control scheme. The analysis of the results provides a specific insight on the characteristics of the synchronizing interactions between the different types of grid-forming converters, indicating the possibility of steep reactions, mutual oscillations and unsymmetrical interactions
The 10-Bus Model of the Italian Power System: A Tool for Multi-Site Co-Simulations
No full textThe paper presents the 10-bus model of the Italian power system, with a particular focus on the opportunity of using the model for multi-site co-simulations. The model is a simplified version of the Italian power system, where the main structure of the 380 kV transmission system interconnecting southern and northern Italy is reflected, and the total load and generation are distributed proportionally to the represented regions. The model is developed in MATLAB/Simulink, and it is compiled for real-time simulation with the OPAL-RT technologies. Some possible applications of the model for multi-site distributed co-simulations are introduced and discussed, showing also the suitability of the model in terms of variable multi-site configurations
Transient behaviour of a “mixed” overhead-cable EHV line under lightning events
No full textRecently, in many countries have been undergone or are planning links with AC extra-high voltage (EHV) underground cables. Cable lines offer the possibility of a reduced environment impact and for this reason they are often the only alternative for the reinforcement or the expansion of power system accepted by public opinion. The coexistence of overhead and cable line in the so called ¿mixed¿ lines, however, raises several questions regarding their behaviour both in steady state and in transient. The purpose of this work is to investigate the transient behaviour of a mixed overhead-cable EHV line under lightning events, describing the effects of the following overvoltages on the system. The mixed line analyzed is a known case found in literature: the results obtained by the model are assumed as term of comparison with the known case. The model thus validated is used for further analysis, taking into account different configuration of the mixed system. The events subsequent lightning may be different: the study considers the shielding failure and the direct stroke on tower, with the possibility of back flashover along insulators. The analysis, carried out in PSCAD/EMTDC environment, has shown that shielding failure does not represent a critical event to mixed line and back flashover occurs for fast waveshape and high value of peak current
Transient stability assessment of SMIB System with Mixed overhead-cable line – Sensitivity analysis
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Trust in authorities monitoring the distribution of genetically modified foods: dimensionality, measurement issues, and determinants
No full textBased on a combined internet and mail survey in Germany the independence of indica-tors of trust in public authorities from indicators of attitudes toward genetically modified food is tested. Despite evidence of a link between trust indicators on the one hand and evaluation of benefits and perceived likelihoods of risks, correlation with other factors is found to be moderate on average. But the trust indicators exhibit only a moderate relation with the re-spondents’ preference for either sole public control or a cooperation of public and private bodies in the monitoring of GM food distribution. Instead, age and location in either the New or the Old Lander are found to be significantly related with such preferences
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A critical account of the relationship between institutional trust, risk perception, and technology acceptance with an application to genetically modified foods
No full textThis article critically reflects on the widely held view of a causal chain with trust in public authorities impacting technology acceptance via perceived risk. It first puts forward conceptual reason against this view, as the presence of risk is a precondition for trust playing a role in decision making. Second, results from consumer surveys in Italy and Germany are presented that support the associationist model as counter hypothesis. In that view, trust and risk judgments are driven by and thus simply indicators of higher order attitudes toward a certain technology which determine acceptance instead. The implications of these findings are discussed
PER UNA EDIZIONE CRITICA DELLE RIME DI BARTOLOMEO CAVASSICO
No full textThis PhD thesis consists of:
- An introductory part presenting the figure of the author, a description of the ms. bearing the Rime, an analysis of the form and content of the texts and the social, political and cultural context where they were produced;
- The critical edition of fifty-four poems in italian and fifteen in Bellunese dialect. An introductory cap presents the formal characteristics of the work and provides the context, if necessary; this is followed by the text, reproduced according to generally conservative criteria; at the bottom there is a first band of apparatus, aimed at containing corrections of servile errors; a second band, containing the actual genetic apparatus, bearing any variants or previous redactions of the text; and finally the commentary, aimed at clarifying critical places and pointing out parallels with other authors. For the Bellunese texts, a full translation was also provided.
- A caption index;
- Two lexical indexes, for italian and Bellunese texts, bearing the notable forms;
- Four appendices. Appendix I is a table containing all the poems, classified according to the following criteria: location in the ms., title, genre of the poem, language, possible addressee and brief summary, focusing, in particular, on the (recurring) themes present in the text. Appendix II houses vernacular texts not included in the edition, and Appendix III italian texts that the author has taken from other printings. Appendix IV contains the digital reproduction of six papers from ms. 396 of the Biblioteca Civica of Belluno.Questa tesi di dottorato si compone di:
- Una parte introduttiva che presenta la figura dell'autore, la descrizione del ms. recante le Rime, l'analisi della forma e dei contenuti dei testi e il contesto sociale, politico e culturale in cui sono stati prodotti;
- L'edizione critica commentata di cinquantaquattro poesie in volgare e quindici in dialetto bellunese. Un cappello introduttivo presenta le caratteristiche formali dell'opera e ne fornisce il contesto, qualora necessario; segue il testo, riprodotto secondo criteri generalmente conservativi; in calce si trovano una prima fascia di apparato, volta a contenere le correzioni degli errori servili, una seconda fascia, contenente l'apparato genetico vero e proprio, recante le eventuali varianti o redazioni precedenti del testo, e infine il commento, finalizzato a chiarire i luoghi critici e a segnalare paralleli con altri autori. Per i testi bellunesi si è fornita anche la traduzione integrale in calce.
- Un indice dei capoversi;
- Due indici lessicali, per i testi in volgare e per i testi in bellunese, recanti le forme notevoli;
- Quattro appendici. L'appendice I è una tabella contenente tutti i componimenti, classificati secondo i seguenti criteri: collocazione nel ms., titolo, genere del componimento, lingua, eventuale destinatario e breve riassunto, imperniato, in particolare, sui temi (ricorrenti) presenti nel testo. L'appendice II ospita i testi in volgare non inclusi nell'edizione, mentre l'appendice III i testi in volgare che l'autore ha tratto da altre stampe. L'appendice IV contiene la riproduzione digitale di sei carte del ms. 396 della Biblioteca Civica di Belluno, attraverso la quale si possono osservare la scrittura del notaio e gli interventi sui testi
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