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Fluorescent lamps are among the most diffuse electrical components that introduce significant waveform distortions in low voltage distribution systems. These distortions involve a wide range of frequencies (i.e., from 0 kHz to 150 kHz), and spectral components characterized by a non-uniform behavior in time and frequency domains. Early IEC standards covered formally only the range from 0 kHz to 9...
In this paper we propose different strategies for the scheduling of unbalanced microgrids, characterized by the presence of a variety of distributed resources such as datacenters, electric vehicles and distributed generation systems. The operation strategies are based on the solution of single-objective optimization problems, whose objective functions are related to specific services and requirements...
In this paper an optimal strategy is proposed for the real time control of a hybrid microgrid (μG). Hybrid μGs are characterized by the presence of two sections operating in alternating current (AC μG) and in direct current (DC μG), respectively. They include dispatchable and non-dispatchable renewable generation units, battery energy storage systems and controllable loads. These different resources...
The management of micro grids requires the dynamic harmonic state estimation of the system in order to perform control strategies that optimize waveform distortions. In industrial context, AC and DC devices and sources coexist and, therefore, micro grids can be a hybrid combination of AC and DC power sections. Also for such hybrid AC/DC micro grids optimal control strategies that optimize waveform...
In this paper, the benefits that can be derived from the installation of an energy storage system in an industrial facility are analyzed, and an optimal control strategy of the storage system is proposed. The proposed control strategy is based on a two-step procedure and aims at (i) reducing the electricity costs sustained by an industrial customer that provides demand response and (ii) satisfying...
This is the companion paper to “Part I: theoretical aspects”. In Part I a new procedure was proposed in order to control an energy storage system installed in an industrial facility. The control strategy, based on the combined use of day ahead scheduling and very short time predictive control, aims at minimizing the cost suffered by the industrial owner for energy consumption and satisfying constraints...
The ability to forecast photovoltaic (PV) power-production accurately and reliably is of primary importance for the appropriate management of the future distribution systems and for making decisions to satisfy the needs of all the stakeholders of the electricity energy market. Several forecasting methods have been proposed in the relevant literature and many indices have been used to quantify the...
The sensitivity to Power Quality (PQ) disturbances is today increasing in micro grids due to the great economic consequences that PQ disturbances can generate. However, micro grids include several distributed energy resources (DER) interconnected to the grid with static converters that can deteriorate the Power Quality levels. Among DER, wind turbine systems (WTSs) are expected to be widely employed...
This is a companion paper to a paper of the same title, Part I, in which the theoretical aspects of some spectrum estimation methods for the analysis of non-stationary waveform distortions in power systems due to Wind Turbine Systems (WTSs) are analysed. In particular, Part I dealt with sliding window (SW) DFT, some parametric methods (SW Prony and ESPRIT) and some hybrid methods (SW ESPRIT-DFT and...
Electrical storage systems are a potential solution for some challenges that will face future Smart Grids due to the large number and variety of services they can perform. These services can be further enlarged if an optimal operation of the storage systems is guaranteed. This paper deals with the energy management of battery storage systems in the frame of real time pricing. An optimal control strategy...
Microgrids 1 are electrical subsystems which include small generation units, storage devices and loads, which can operate either in grid connected or islanding mode. This paper deals with a DC microgrid that will be realized in an Italian industrial facility of GETRA Group. In particular, in this paper an optimization model is formulated to solve the problem of the day-ahead optimal scheduling of...
This paper proposes a real time control strategy of battery systems in the frame of dynamically varying energy pricing. The battery, which is supposed to operate in a large industrial facility, is managed in order to reduce the daily costs sustained by the industry owner for the energy consumption. Multi-battery configurations are taken into account and an optimization model is formulated and solved...
Discrete Fourier Transform (DFT) and high-performance signal-analysis techniques (i.e., Prony, ESPRIT, root-MUSIC methods) have been proposed to calculate Power Quality indices that characterize waveform distortions in power systems. DFT can be affected by spectral leakage problems that cause inaccuracies in the spectral component calculation while high-performance signal-analysis techniques usually...
Electrical energy storage systems can provide several benefits along the entire value chain of the electrical system. In this paper attention is paid to the end user point of view, with particular reference to industrial customers. An optimal operating strategy is proposed for energy storage systems with the aim of reducing the electricity bill costs sustained by an industrial customer and contemporaneously...
In recent years, modern distribution networks are rapidly evolving toward the new concept of Smart Grid (SG) due to the increasing level of penetration of distributed generation (DG) units, storage systems and information and communication technologies. In the framework of low voltage distribution systems, SGs based on either AC or DC grids have been proposed and compared in the technical literature,...
This is the companion paper to “Part I: theoretical aspects”. Part I reviews and critically analyses some of the most significant single-objective optimization methodologies proposed for the optimal operation of plug-in electric vehicles (PEVs) operating in Smart Grids. This Part II applies the models presented in Part I to a low voltage test Smart Grid. Analysis of the results highlights the behavior...
Plug-in Electric Vehicles (PEVs) could become remarkable resources for improving quality and reliability of future grids, if adequate control of their onboard storage systems is provided. Hence, the problem of PEVs optimal control strategies is a crucial topic of research in modern power system operation. This is particularly true in the Smart Grid (SG) context, where the presence of bi-directional...
This paper deals with Smart Grids including renewable generation plants and plug-in vehicle fleets managed by aggregators and connected to the grid through power electronic devices. A new multi-objective optimization model is proposed in order to obtain the optimal operation of the Smart Grids. The proposed model originates from the need of accomplishing numerous and sometime conflicting objectives...
In this paper, the point estimate method is applied to account for the uncertainties that affect the evaluation of the steady state operating conditions of an unbalanced three-phase power system in the presence of wind farms. The accuracy of the proposed technique is tested on the three-phase unbalanced IEEE 34-bus test system adequately modified to take into account the presence of wind farms; the...
Power quality (PQ) regulation is of great importance due to the economical consequences associated with the presence of the disturbances in power systems. Regulations should provide interventions at the system level (transmission and distribution networks) and the local level at the point of common coupling between utilities and customers. This paper proposes an integrated approach for overall voltage...
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