Search results for "NEWA"
showing 10 items of 2491 documents
Impact of RES penetration on the frequency dynamics of the 500 kV vietnamese power system
2019
The increase of renewable energy sources (RES) typically operating as converter-interfaced generation (CIG) is progressively causing a significant change of power systems operation paradigm. The reduction of the overall available kinetic energy and the consequent impact on the dynamic response of the system is a relevant issue currently under investigation in academic and industrial scopes. The work analyzes the impact of different CIG penetration in the three areas of the 500 kV Vietnamese power system, North, Center and South. The system is modified substituting conventional synchronous generation with converter-interfaced generation. The models of power converters and corresponding contr…
System Stability of a Small Island's Network with Different Levels of Wind Power Penetration
2018
The reduction of the inertial response of the generation system has been one of the main obstacles to the penetration of high sharing of renewable energy sources in islanded systems. This issue can be solved thanks to innovative control that makes wind turbines able to provide the so-named synthetic inertia. The paper investigates some scenarios with different levels of wind power penetration in a small island whose grid is not supplied by the main grid, by the use of the software NEPLAN 360, simulating the wind power plants accordingly to the standard IEC 61400-27. The aim of the paper is to assess the maximum level of penetration in the island of wind generation, with traditional control …
An Analysis of the Intertial Response of Small Isolated Power Systems in Presence of Generation from Renewable Energy Sources
2018
Renewable Energy Sources are posing critical issues related to the mining of power systems stability, essentially due to a decrement of the inertial response during system's contingencies. As a consequence, to preserve the security and the reliability of the system, it is necessary to adopt new frequency adjustments mechanisms. This issue becomes particularly critical in isolated power systems, like those of small islands not supplied by the main grid, in the case of high shares of production from unpredictable renewabies such as photovoitaic and wind sources. In this framework, the present work deals with the analysis of the variation of the inertia time constant of a small island in vario…
Tuning the selectivity of light hydrocarbons in natural gas in a family of isoreticular MOFs
2017
Purification of methane from other light hydrocarbons in natural gas is a topic of intense research due to its fundamental importance in the utilization of natural gas fields. Porous materials have emerged as excellent alternative platforms to conventional cryogenic methodologies to perform this task in a cost- and energy-efficient manner. Here we report a new family of isoreticular chiral MOFs, prepared from oxamidato ligands derived from natural amino acids L-alanine, L-valine and L-leucine, where, by increasing the length of the alkyl residue of the amino acid, the charge density of the MOF's channels can be tuned (1 > 2 > 3), decreasing the adsorption preference towards methane over lig…
The energy and environmental impacts of Italian households consumptions: An input–output approach
2011
Abstract Promoting sustainable consumption and production patterns is a key challenge for the future, in order to use the Earth resources efficiently, to reduce the greenhouse gas emissions, and to decouple the economic growth from the environmental degradation. New or customized methods have to be applied to support decisions makers in the choice of environmental-friendly products, and to select policy priorities and sustainable strategies. A modified input–output model can aid to analyse the relationships among economic growth, energy consumptions and pollutants, in order to assess the energy and environmental impacts due to the actual production and consumption patterns. The following pa…
Rigenerazione urbana e pratiche urbane microspaziali
2017
Nello scenario post-crisi attuale, che ha visto la sensibile riduzione delle risorse pubbliche per i progetti di rigenerazione urbana, in molte realtà urbane italiane e non solo, stiamo assistendo alla crescita di una serie di pratiche urbane micro-spaziali che stanno ridisegnando gli spazi urbani. Si tratta di esperienze che diversi studiosi hanno definito come "insurgent", "do-it-yourself" (DIY), "guerrilla", "everyday", "participatory" e/o "grassroots" urbanism (Haydn and Temel, 2006; Borasi and Zardini, 2008; Chase et al., 2008; Burnham, 2010; Hou, 2010; Zeiger, 2011a) e che si caratterizzano per una capacità proattiva che sfida gli approcci tradizionali delle politiche urbane e le loro…
Reconfigurable electrical interconnection strategies for photovoltaic arrays: A review
2014
Non-uniform irradiance significantly decreases the power delivered by solar photovoltaic arrays. A promising technique for compensating these power losses relies on dynamically reconfiguring the electrical connections between photovoltaic modules. This paper presents the current state-of-the-art strategies for photovoltaic array reconfiguration in order to increase the power output under partial shading and mismatch conditions. The different approaches have been compared in terms of effectiveness of the control algorithms, monitored electrical and environmental variables, overall hardware complexity and specific features of each solution. Finally, the most challenging aspects of the reconfi…
Interface reactivity study between La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode material and metallic interconnect for fuel cell
2011
Abstract Interface reactivity between La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode material and metallic interconnect (Crofer22APU) was investigated in laboratory air at 700 °C. Due to the interconnect geometry, two interfaces have been analysed: (i) interconnect rib/cathode interface (physically in contact); (ii) the interface under the channel of interconnect. In both cases, formation of a parasite phase was observed after various ageing treatments (20 h, 100 h and 200 h). However, the growth of the determined SrCrO4 parasite phase depends on interface type and on ageing time. Two different mechanisms have been established in function of interface type: (i) SrCrO4 phase was formed after solid …
Energetic macroscopic representation and inversion based control of fuel cell in a series hybrid race vehicle system
2020
This paper studies the replacement of engine and generator as range extender in a hybrid racing car with a fuel cell system. A model of the original system of the car using range extender consisting of an internal combustion engine and electric generator has been developed respecting the action-reaction principle used by energetic macroscopic representation (EMR) and its inversion based control (IBC) to organise its subsystems interconnection according to the physical causality. Results from drive tests of the real car on racing circuit are used to validate the model. The objective of this paper is to study the parameterisation and the integration of fuel cell stack components based on this…
Benefits from energy policy synchronisation of Brazil’s North-Northeast interconnection
2020
Abstract During the last 10 years Brazil has accelerated the incorporation of new wind capacity into its power matrix. This situation has generated the need for increased transport capacity. However, there have been delays in the planning process for new transmission line construction, thus inducing trapped electricity in the system; in other words, electricity that cannot be dispatched to the interconnected system. Using system dynamics modelling, this paper assesses energy policy alternatives for improving the synchronisation between the construction of both power generation and transmission capacities. Simulation results show that policy synchronisation within the wind industry may provi…