Search results for "flow analysis"
showing 10 items of 20 documents
Simple measures to improve the performances of the backward/forward method for radial distribution network analysis
2005
In the paper, after having presented the general backward/forward methodology for radial systems analysis, the main changes that have been proposed in the past to improve their convergence and speed performance are shown. Some measures aimed at a further reduction of the number of iterations and calculation times are here described. In order to identify, among the available alternatives, the best methodology, in terms of precision and/or speed of convergence, some evaluations on networks taken from the literature have been carried out. The analysis of the attained results allows the definition, on the basis of specific features of the problem at hand, the most suitable configuration to be i…
An Efficient Procedure for Solving Radial Distribution Networks through the Backward/Forward Method
2005
In the paper, after having presented the general backward/forward methodology for radial systems analysis, a new b/f procedure showing some interesting features that improve its performance in terms of convergence speed and calculation effort is presented. The features that fundamentally are responsible for such improvements concern the main steps of the b/f procedure. The starting voltage profile solution is different from the flat profile and is suitably modified. In the backward phase and starting from the second iteration, the branch currents variations due to the loads changes are evaluated; the latter variations are calculated on the basis of the difference of nodal voltages at the be…
Load flow analysis of radial distribution networks: New findings in backward/forward method
2005
In the paper, the backward/forward method for solving radial distribution networks is in details described. In particular it is examined considering the four main steps into which it can be divided: initialization of the state variables; backward sweep; forward sweep; identification of a convergence criterion. For each of these, except for the forward sweep, a new procedure is defined. In particular, a methodology for the identification of a starting solution that is as close as possible to the desired one is proposed; the backward phase is modified for the evaluation of the branch currents and a new convergence criterion is proposed. The results of the application of the proposed methodolo…
An analytical model for PQ sources in backward/forward methods for distribution networks analysis
2004
In this paper a model of PQ sources useful for distribution systems analysis is developed. In the considered systems there are, in addition to HV/MV sources, other PQ buses, namely active and reactive power supply nodes (Vδ nodes). The general solution strategy is an iterative forward/backward method, in which the state variables are the node voltages. If it is weakly meshed, the network is turned into radial by means of cuts and compensation currents. After the presentation of the general problem, the equations expressing the unknowns for the PQ nodes are treated in detail. These equations belong to the backward sweep of the algorithm. The methodology has been implemented and applied so as…
A new model of PV nodes in distribution networks backward/forward analysis
2004
In this paper a new model of PV nodes is developed; the model is aimed for the distribution systems load flow analysis and, in particular, for the iterative forward/backward method. If the network is weakly meshed, it is turned into radial by means of cuts and compensation currents. After the presentation of the general problem and the state of the art on the subject, the equations expressing the unknowns for the PV nodes are treated in detail. These equations belong to the forward sweep of the algorithm. The methodology has been implemented and applied so as to test its performance in terms of calculation times and precision. The obtained results confirm the efficiency of the proposed appr…
An integrated approach of analytical chemistry
1999
The tremendous development of physical methods of analysis offers an impressive number of tools to simultaneously determine a large number of elements and compounds at very low concentration levels. Todays Analytical Chemistry provides appropriate media to solve technical problems and to obtain correct information about chemical systems in order to take the most appropriate decisions for problem solving. In recent years the development of new strategies for sampling, sample treatment and data exploitation through the research on field sampling, microwaveassisted procedures and chemometrics, additionally the revolution of the analytical methodology provided by the development of flow analysi…
Agronomic performance and energetic potential of two Brassica oilseed species in Sicily, Italy
2018
Industrial crops for energy purposes are object of increasing interest worldwide and play an important role as a source of renewable energy. The aims of this study were to evaluate: i) the agronomic performance of Brassica napus L. var. oleifera D.C. and Brassica carinata A. Braun in a semi-arid environment; ii) to evaluate the economic viability of a pilot combined heat and power (CHP) plant operating on pure vegetable oil (PVO). The research was carried out in Sicily (Italy). The main biometric and yield parameters of the two species were determined. Chemical-physical characterizations were carried out on PVO for each species using specific protocols. The cogeneration of renewable energy …
Renewable Energy Technologies for Economic Development
2020
Indonesian villages are facing dangerous condition. Every year, young people are deserting the villages. To overcome this problem, Tangsi Jaya hamlet, West Java, has been provided with 18 kW micro-hydro to supply electricity both to the community and to Small Processing Center for ground coffee production. Results of cash flow analysis for ground coffee in Tangsi Jaya hamlet, with total investment of IDR 110 750 000 and discount rate of 18 % for 5 yr. Banyumeneng I hamlet, Yogyakarta with an investment cost IDR 95 000 000 and production cost of IDR 34 195 000 yr–1 and the interest rate of 14 % yr–1, the payback period was estimated to be 3 yr with ROI of 40 %. PEST analysics indicate that t…
The Origin of Non-thermal Fluctuations in Multiphase Flow in Porous Media
2021
Core flooding experiments to determine multiphase flow in properties of rock such as relative permeability can show significant fluctuations in terms of pressure, saturation, and electrical conductivity. That is typically not considered in the Darcy scale interpretation but treated as noise. However, in recent years, flow regimes that exhibit spatio-temporal variations in pore scale occupancy related to fluid phase pressure changes have been identified. They are associated with topological changes in the fluid configurations caused by pore-scale instabilities such as snap-off. The common understanding of Darcy-scale flow regimes is that pore-scale phenomena and their signature should have a…
The efficiency of the incentives for the public buildings’ energy retrofit. The case of the Italian Regions of the “Objective Convergence”
2017
Gli obiettivi di riduzione del consumo energetico e delle emissioni di gas serra, enunciati in molte Direttive europee, hanno posto in risalto la necessità di promuovere interventi di miglioramento dell’efficienza energetica del patrimonio edilizio esistente. Le amministrazioni locali, in particolare, dovrebbero assumersi la responsabilità di diffondere la cultura ambientale anche effettuando interventi di retrofit negli edifici pubblici di loro proprietà, sulla base di diagnosi energetiche degli edifici, di proposte progettuali e di verifiche del raggiungimento della convenienza finanziaria, che può essere agevolata dall’erogazione di incentivi. L’Unione Province d’Italia (UPI) nel 2013, n…