A. Pinnarelli

Energy Management System for an Energy District With Demand Response Availability

During recent years the electricity supply chain (electricity production, consumption, distribution, storage, and load management) has changed. In this context a new term appears: the prosumer, that is both a consumer and producer of energy in the same entity. In the paper, an energy management approach of several prosumers aggregated in a coalition, the energy district (ED), and coordinated through a central control entity, the coalition coordinator, is proposed. The aim of the coalition coordinator is to maximize the coalition utility also reducing in this way the reverse energy flows at the point of delivery by an appropriate demand response program. The application on an Italian residential housing area is illustrated. The numerical results demonstrate the effectiveness and attractiveness of the proposed energy management scheme.

An incremental conductance method with variable step size for MPPT: Design and implementation

In this paper the authors propose a novel method for tracking the maximum power point of a PV array. This method is derived by the well known incremental conductance method and the novelty consists in varying the duty cycle of the dc-dc switching converter used as MPPT tracker using a variable step size instead of a fixed step size. A practical way to determine the minimum and the maximum values of the variable step size is explained in detail. The laboratory results demonstrate the effectiveness of the proposed method both in terms of speed in MPP tracking and accuracy in the MPP individuation.

In the future Smart Cities: Coordination of micro Smart Grids in a Virtual Energy District

In the future Smart City, new information and communication technologies will enable a better management of the available resources. The Smart Grid infrastructure is emerging as a complex system where fine-grained monitoring and control of energy generating and/or consuming entities within the electricity network is possible. This will result to better approaches that will boost energy efficiency. To make real this vision, (open) platforms providing access to the smart meter data as well as potential management and value-added functionalities are needed. These will offer basic energy services that can be commonly used by application developers. In this context, this paper proposes a new market platform in order to coordinate the energy exchanges among several micro Smart Grids aggregated in a Virtual Energy District. Some numerical results in Matlab/Simulink environment are presented to validate the proposed platform.

Power management by grid-connected inverters using a voltage and current control strategy for Microgrid applications

This paper presents the application of a suitable control strategy for multibus microgrid applications. The control strategy, used with each distributed generation system in the microgrid is developed so as to combine the advantages of the current control and the voltage control strategies. The performance of the proposed application in terms of power management has been verified in simulation on a microgrid test.

Grid-interfacing active power filters to improve the power quality in a microgrid

This paper proposes the application of the strategy control approach used for the shunt active power filter previously proposed by the authors to the inverter interface of each single micro-sources present in a Microgrid. In particular the attention has been focused on the power quality and var supporting issues. The main advantage of the proposed strategy control approach lies on the fact that all sensitive loads connected to the Point of Common Coupling (PCC) are immunized from the power quality problems. Moreover, the proposed control approach requests only local information. The effectiveness of the proposed control strategy approach applied to a Microgrid is illustrated.

Management of storage systems in local electricity market to avoid renewable power curtailment in distribution network

The increase of small size generation systems may cause congestions, hitherto unexpected, on the distribution network. To reduce the impact of congestions, the use of storage systems is one of the main countermeasure. In the paper, a storage management strategy based on a local energy market is proposed, in order to maximize the utility of an users community in which local market takes place. The numerical results obtained and shown in the paper demonstrate the effectiveness of the proposed management strategy2.

An hybrid PV-wind supply system with D-Statcom interface for a water-lift station

In the last years the photovoltaic and wind power generation has been increased significantly. This paper proposes the use of a D-Statcom as inverter interface of each single micro-sources (PV and wind) present in the supply system for a water lift station situated in Marina of Strongoli (KR- Italy) for the reactive compensation to regulate PCC voltage. The power circuit topology and the network are modeled by using ATP/EMTP software. The description of power system model, of the strategy control, of the Phase Locked Loop, and of the measurement system, are derived and presented. Some numerical results are illustrated.

Implementation of a novel fuzzy-logic based MPPT for grid-connected photovoltaic generation system

This paper presents modeling and simulation of a grid connected photovoltaic (PV) generation system with maximum power point tracking (MPPT) using a novel fuzzy logic controller (FLC). The system is composed of a PV array, boost converter with MPPT and a single phase inverter connected to utility grid. The MPPT is based on fuzzy logic to control IGBT switch of the boost converter. The performance of the proposed FLC for MPPT is evaluated by simulation and the results show that the FLC is more efficient in finding the maximum power point than the conventional incremental conductance method when the PV system is subjected to variations in external operating conditions (insulation level and module temperature).

Reliability studies of a PV-WG hybrid system in presence of multi-micro storage systems

In the last years, distributed generation (DG) and microgrid (MG) technologies have been used to moderate the stress due to main stream utility grid electricity demand increase. The dispatch of renewable distributed energy sources at present is performed in such a way that, when implemented at very large scale, their intermittency can impact on the grids, what leads to concerns in terms of power quality and of reliability of supply. In this paper the attention is focused on MG reliability. On this subject the authors have proposed, in previous papers, opportune configuration schemes of MG constituted by a photovoltaic plant, a Wind plant and an Uninterruptible Power Supply. The goal of this paper is to evaluate the reliability improvements of load supply against network congestions adopting the proposed hybrid configurations in presence of storage systems for each energy source proposing an opportune operating strategy for the energy control system. In particular, the reliability estimation is performed in terms of the number of the critical loads interruptions and in particular of the charge state of storage systems, over a certain period of time by using the Monte Carlo simulation method.

Grid-connected inverters for alternative energy sources with a combined voltage and current control strategy

Renewable energy sources are considered as important generation alternatives in electric power systems due to their no exhausted nature and benign environmental effects. In order to utilize the infrastructure of the actual distribution network, grid-connected inverters are needed. In this paper a new control strategy for a pulse width modulation (PWM) three-phase voltage source inverter (VSI) connected to the grid and able to support bi-directional power flow is presented. In particular, the proposed strategy is developed so as to combine the advantages of the current control and the voltage control. The effectiveness of this combined control strategy is proved by some numerical results compared with those obtained applying only the conventional current control strategy.