Multiconductor Cell Analysis of AC High Speed Railway Lines

The aim of this article is the application of Multiconductor Cell Analysis (MCA) to a very special case of a multiconductor system, i.e., the AC high-speed railway system, with 14 parallel conductors. The present matrix approach allows representing both the single elements and the entire railway system also including the high-voltage (HV) three-phase supply network. The algorithm allows computing all the steady-state regime electrical quantities (voltages, currents, and power) of each section: in particular, the ground return current, responsible for electromagnetic interferences (EMIs), can be derived by the knowledge of all the circulating currents. It is also possible to evaluate the electric unbalance impact on the supply three-phase power system given by the railway system. Eventually, two different scenarios are presented, i.e., a maximum allowable high-speed line power request and a contact-wire-to-rail short circuit

Synergy of the future: High voltage insulated power cables and railway-highway structures

The rationalisation of the territorial resources leads to consider carefully the possibilities of using motorway and railway infrastructures (existing or planned ones) for cable line installation within them. The full compatibility of such synergy \u2018transport \u2013 electrical power transmission\u2019 involves different branches of engineering. The study provides an overview of the research undertaken for a fully reliable use of this combination. The manuscript aims at highlighting a procedural approach that should be followed in order to analyse all the key elements involved in the safe operation of power transmission lines hosted in transport infrastructures. First, the geometrical compatibility between different types of power transmission technologies, (i.e. gas insulated lines and high-voltage direct/alternating current insulated cable lines), and transport infrastructures (i.e. motorway galleries, railway galleries and railway prospection tunnels) is considered. Subsequently, the behaviour and magnitude of the magnetic field generated by the different power transmission technologies inside the transport infrastructures are presented. Moreover, the study analyses the effects of a phase-to-screen short circuit that could occur inside the hosting facility. Finally, an analysis of the reliability of the synergy between power transmission systems and transport infrastructures is discussed

A Novel AC/DC Power Flow: HVDC-LCC/VSC Inclusion Into the PFPD Bus Admittance Matrix

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ground return current behaviour in high voltage alternating current insulated cables

The knowledge of ground return current in fault occurrence plays a key role in the dimensioning of the earthing grid of substations and of cable sealing end compounds, in the computation of rise of earth potential at substation sites and in electromagnetic interference (EMI) on neighbouring parallel metallic conductors (pipes, handrails, etc.). Moreover, the ground return current evaluation is also important in steady-state regime since this stray current can be responsible for EMI and also for alternating current (AC) corrosion. In fault situations and under some assumptions, the ground return current value at a substation site can be computed by means of k-factors. The paper shows that these simplified and approximated approaches have a lot of limitations and only multiconductor analysis can show the ground return current behaviour along the cable (not only the two end values) both in steady-state regime and in short circuit occurrence (e.g., phase-to-ground and phase-to-phase-to-ground). Multiconductor cell analysis (MCA) considers the cable system in its real asymmetry without simplified and approximated hypotheses. The sensitivity of ground return current on circuit parameters (cross-bonding box resistances, substation earthing resistances, soil resistivity) is presented in the paper

Análise do processo de incorporação de cooperativas

Cooperativism is a movement capable of uniting economic development and social welfare, having as its fundamental cornerstones a democratic participation, solidarity, independence and autonomy, so the participation of members in the cooperative is important for performance and good management. The modernization of cooperation takes different business forms, which makes it necessary for cooperatives to seek alternatives and management strategies for the cooperative society as a whole, one of which is incorporation. In this sense, the objective of this work is to analyze the process of incorporating five cooperatives that formed a new cooperative, analyzed by the point of view of the associate. For this, a descriptive research with quantitative approach (survey) was carried out that allowed to verify and present a diagnosis of the perception of the associates about the cooperative resulting from the incorporation, through 248 valid questionnaires. The questionnaire was build by four dimensions: cooperative management, associate management, infrastructure and agricultural technical training. The results show the general perceptions of the associates and point out the importance of attendance, management, infrastructure and technical assistance, as the main responsible for the satisfaction, trust and commitment of the associates.El cooperativismo es un movimiento capaz de unir el desarrollo económico y el bienestar social, teniendo como pilares fundamentales la participación democrática, la solidaridad, la independencia y la autonomía; Por lo tanto, la participación de los miembros de la cooperativa es importante para el desempeño y la buena gestión. La modernización de la cooperación supone diferentes formas de negocio, lo que hace necesario que las cooperativas busquen alternativas y estrategias de gestión para la sociedad cooperativa en su conjunto, una de las cuales es la incorporación. En este sentido, el objetivo de este trabajo es analizar el proceso de incorporación de cinco cooperativas que formaron una nueva cooperativa, analizada desde el punto de vista del asociado. Para ello, se realizó una investigación descriptiva con enfoque cuantitativo (encuesta) que permitió verificar y presentar un diagnóstico de la percepción de los asociados sobre la cooperativa resultante de la incorporación, a través de 248 cuestionarios válidos. El cuestionario se construyó en cuatro dimensiones: gestión cooperativa, gestión asociada, infraestructura y capacitación técnica agrícola. Los resultados muestran las percepciones generales de los asociados y señalan la importancia de la asistencia, gestión, infraestructura y asistencia técnica, como los principales responsables de la satisfacción, la confianza y el compromiso de los asociados.O cooperativismo é um movimento capaz de unir desenvolvimento econômico e bem-estar social, tendo como pilares fundamentais uma participação democrática, solidariedade, independência e autonomia; portanto, a participação dos membros da cooperativa é importante para o desempenho e a boa gestão. A modernização da cooperação assume diferentes formas de negócios, o que torna necessário que as cooperativas busquem alternativas e estratégias de gestão para a sociedade cooperativa como um todo, uma das quais é a incorporação. Nesse sentido, o objetivo deste trabalho é analisar o processo de incorporação de cinco cooperativas que formaram uma nova cooperativa, analisada pelo ponto de vista do associado. Para isso, foi realizada uma pesquisa descritiva com abordagem quantitativa (survey) que permitiu verificar e apresentar um diagnóstico da percepção dos associados sobre a cooperativa resultante da incorporação, através de 248 questionários válidos. O questionário foi construído em quatro dimensões: gestão cooperativa, gestão de associados, infraestrutura e treinamento técnico agrícola. Os resultados mostram as percepções gerais dos associados e apontam a importância do atendimento, gestão, infraestrutura e assistência técnica, como os principais responsáveis pela satisfação, confiança e comprometimento dos associados

A Three-Phase Power-Flow Algorithm for Transmission Networks: a Hybrid Phase/Sequence Approach

In this paper, the three-phase generalization of a single-phase power flow (named PFPD) developed by the first author is presented. This three-phase formulation is chiefly conceived for HV/EHV transmission network applications, but it preserves a general validity for any power system. An iterative method for the solution achievement is throughout expounded. The algorithm quantitatively aims at investigating the impact of the asymmetrical transmission structures on power systems. This impact is evaluated in terms of voltage and current sequence components. Moreover, discussions on possible improvement actions to enhance the power quality are developed. The algorithm is implemented in Matlab environment and tested by several fictitious networks. Eventually, extensive comparisons in terms of execution time, number of iterations and solution accuracy with the software DIgSILENT PowerFactory are presented

Review of Power Conversion and Conditioning Systems for Stationary Electrochemical Storage

This paper deals with the power conversion system architectures to interface a stationary electrochemical storage installation with the network. Theoretical justifications about the conversion system layouts and control, used for actual Italian installations, are given. This paper aims at giving the power energy society an overview of actual possibilities of static conversion of d.c. battery sources

Rational modifications, synthesis and biological evaluation of new potential antivirals for RSV designed to target the M2-1 protein

Respiratory syncytial virus (RSV) is the main cause of lower respiratory tract diseases in infants and young children, with potentially serious and fatal consequences associated with severe infections. Despite extensive research efforts invested in the identification of therapeutic measures, no vaccine is currently available, while treatment options are limited to ribavirin and palivizumab, which both present significant limitations. While clinical and pre-clinical candidates mainly target the viral fusion protein, the nucleocapsid protein or the viral polymerase, our focus has been the identification of new antiviral compounds targeting the viral M2-1 protein, thanks to the presence of a zinc-ejecting group in their chemical structure. Starting from an anti-RSV hit we had previously identified with an in silico structure-based approach, we have designed, synthesised and evaluated a new series of dithiocarbamate analogues, with which we have explored the antiviral activity of this scaffold. The findings presented in this work may provide the basis for the identification of a new antiviral lead to treat RSV infections

Curvature-Based Control for Low-Inertia Systems

This letter proposes a simple and inexpensive control of distributed energy resources aimed at improving the power system dynamic performance. The rationale behind the proposed control relies on a recent interpretation of the frequency in the differential geometry framework. A comparison with well-established controls in terms of eigensensitivity and time-domain performance is carried out to show the effectiveness of the proposed control.Italian Ministry of EducationSustainable Energy Authority of Irelan

An Original Educational Algorithm Assessing the Behaviours of Angular Frequency Deviations of a Multimachine System in Small Signal Analysis

The paper presents a fully self-implementable algorithm that has demonstrated to be an effective tool for power education at the University of Padova-Department of Industrial Engineering. It deals with the small signal analysis of the electromechanical transients of a multimachine system. The algorithm allows analytically building both the state matrix and the input matrix. Moreover, by exploiting the matrix exponential, the angular frequency deviations of synchronous generators can be computed and plotted so to help students to evaluate transient stability. Besides the full exposition of the algorithm, the paper presents a comparison between a self-implemented linearized dynamic in Matlab environment and the dynamic simulation obtained by the commercial software DIgSILENT PowerFactory