Search results for "33"

Fundamental Analysis of Grid-Forming Converters Enhanced with Feedforward Controls

2022

The grid-forming control for power converters can be enhanced by proper feedforward terms included in the active power control loop. Two basic structures are identified, the feedforward angle and the feedforward frequency. The formal analysis of the transfer functions reveals a structural similarity. The two schemes exhibit however a fundamental difference in their transient capabilities. The grid-forming controls are characterized with the introduction of two specific factors, for the direct assessment of the inertia and the damping which can be provided by the grid-forming converter. The sensitivity analysis of the two feedforward schemes indicates that the enhancement of the transient pe…

Life Cycle Energy Consumption and Air Emissions Comparison of Alternative and Conventional Bus Fleets in Vietnam

2022

The study (a) assesses the life cycle energy consumption and air emissions impacts of battery electric buses (e-buses) and conventional buses operated in Vietnam, and (b) compares them with those of hydrogen buses. The results indicate that e-buses and hydrogen buses are preferred options compared to conventional buses in terms of energy consumption, GHG emissions and other air quality impacts over their whole life cycle. Life cycle energy consumption of diesel buses is triple that of e-buses, and is significantly higher than that of hydrogen buses. Replacing conventional buses with e-buses can reduce energy consumption by 50%. For GHG emissions and air quality impacts, the adoption of elec…

Economic analysis on dynamic photovoltaic systems in new Italian "feed in tariffs" context

2013

Dynamic photovoltaic generators, based on the application of solar-trackers, are able to give an increment to the electric energy production from solar source. Their realization and maintenance costs are certainly higher than those of fixed ones. In this paper the Authors propose a method to estimate the increment of electrical energy generation that must be guaranteed by a dynamic photovoltaic generator, so as its realization could be more favorable with respect to that of a fixed generator one with the same rated power. This method, developed by means of classical economic indexes like the Pay-Back-Period and the Net Present Value, takes in to account the economic incentives for the PV sy…

A load model for EV parking lots

2012

In the next years, electric mobility will be one of the issues electric utilities will have to face. The detailed modeling of the electric load generated by the presence of Electric Vehicles, EV, parking lots will be essential to simulate the different working conditions of new distribution systems. Also the detailed modeling will allow to deduce technical and economical aspects, allowing Distribution Systems Operators to devise the right incentives for EV customers. Such as, or maybe more than, residential loading the EV loading is strongly variable because it is connected to the human behavior, the modeling thus has to include stochastic terms. Moreover, to get realistic load profile for …

2015-2020. Sicily and Italy as Electricity Hub in the Mediterranean Area for the Development of the European Power Grids Interconnections

2015

Falling demand and explosion of Renewable Energy Sources (RES) are redesigning the criteria for planning the power grids interconnections by ENTSO-E. In particular, the interconnections between networks of different countries have been acquiring importance more and more, in view of an unique European market for electricity and an increase of RES. Italy and Sicily, placed in the centre of the Mediterranean Sea, play a fundamental role as a bridge between Central Europe, North Africa area and Mediterranean islands (electricity hub). This paper aims to show how power system exchanges tend to follow the direction from South to North, and how the impact of North-African power – mainly generated …

An integrated platform for electrical modeling of microgrids

2012

Aggregates of loads and generators working coordinated, called microgrids, are new entities appearing at distribution level. In this paper, an integrated platform for energy modeling of microgrids is proposed. The platform allows the evaluation of heat and electrical energy balance terms and of the steady state features of the distribution system supplying the grid. The interface is friendly and allows the positioning of different items, such as co-generators, photovoltaic and wind units, Electric Vehicles parking lots and buildings. The platform is built in Matlab while the interface in Java. Each component of the model can be placed using a CAD facility and each ‘node’ is characterized by…

FLEXIBILITY OPTIMISATION PLATFORMS FOR ENERGY MANAGEMENT OF SMART POWER SYSTEMS

Analisi economico-finanziaria degli investimenti sul fotovoltaico in Italia

2009

Alla luce del meccanismo incentivante vigente in Italia a favore degli impianti fotovoltaici e dei risultati raggiunti in termini di numero di impianti e potenza installata, si riporta un’analisi di sensitività degli indici di redditività dell’investimento e le prospettive di sviluppo potenziale del fotovoltaico in Italia sino al 2020.

A Comparison between RMS and EMT Grid-Forming Implementations in MATLAB/Simscape for Smart Grids Dynamics

2022

The article presents a comparison between phasor RMS and EMT models for grid-forming converters. The specific aspects related to the implementation in Simscape Electrical of MATLAB/Simulink are discussed for both RMS and EMT time-domains. The comparison between the different implementations is performed with the simulation of two widely studied grid-forming schemes, the virtual synchronous machine and the power-synchronization control. The simulation-based comparison examines transient phenomena with different characteristics and time scales, including frequency transients, phase jumps and short-circuit events. Specific indications regarding limitations and suitability of grid-forming model…

A Study of Power-Frequency Dynamics in Isolated Power Networks with 100% Converter-Interfaced Generation

2020

The operation of a system with 100% converter-interfaced generation poses several questions and challenges regarding various aspects of the dynamic characteristics of the system. The effects related to the power-frequency control are among the most relevant issues which need to be investigated. The paper takes into examination the case of an existing isolated power network of a geographical island assuming a completely converter-interfaced generation. The factors playing a fundamental role in the assessment of which sources should be designated to be grid-forming are identified with a small signal model formulation of a generic multiple oscillators system. Simulations and analysis performed…