Search results for "Microgrid"

A Generalized Framework for Optimal Sizing of Distributed Energy Resources in Micro-Grids Using an Indicator-Based Swarm Approach

2014

In this paper, a generalized double-shell framework for the optimal design of systems managed optimally according to different criteria is developed. Optimal design is traditionally carried out by means of minimum capital and management cost formulations and does not typically consider optimized operation. In this paper, the optimized multiobjective management is explicitly considered into the design formulation. The quality of each design solution is indeed defined by the evaluation of operational costs and capital costs. Besides, the assessment of the operational costs term is deduced by means of the solution of a multiobjective optimization problem. Each design solution is evaluated usin…

A double-shell design approach for multiobjective optimal design of microgrids

2010

This work develops a new double shell approach to optimal design for multi-objective optimally managed systems. The cost of each design solution can be defined by the evaluation of operational issues and capital costs. In most systems, the correct definition of operational issues can be deduced by means of the solution of a multi-objective optimization problem. The evaluation of each design solution must thus be deduced using the outcome of a multi-objective optimization run, namely a Pareto hyper-surface in the n-dimensional space of operational objectives. In the literature, the design problem is usually solved by considering a single objective formulation of the operational issue. In thi…

OPTIMAL POWER FLOW IN ISLANDED MICROGRIDS

In this thesis, studies about OPF in islanded MGs have been carried out. First, an original formulation and solution approach for the OPF problem in islanded distribution systems is proposed. The methodology is well suited for AC microgrids and can be envisioned as a new hierarchical control structure comprising only two levels: primary and tertiary regulation, the latter also providing iso-frequency operating points for all units and optimized droop parameters for primary regulation. The OPF provides a minimum losses operating point for which voltage drops are limited and power sharing is carried out according to the most adequate physical properties of the infrastructure thus giving rise …

Energy Management Systems and tertiary regulation in hierarchical control architectures for islanded microgrids

2015

In this paper, the structure of the highest level of a hierarchical control architecture for micro-grids is proposed. Such structure includes two sub-levels: the Energy Management System, EMS, and the tertiary regulation. The first devoted to energy resources allocation in each time slot based on marginal production costs, the latter aiming at finding the match between production and consumption satisfying the constraints set by the EMS level about the energy production in each time slot. Neglecting the efficiency of the different energy generation systems as well as that of the infrastructure for electrical energy distribution, the problem dealt with by the EMS sub-level is linear and can …

Multi-Objective Optimization of Urban Microgrid Energy Supply According to Economic and Environmental Criteria

2019

This study is focused on the optimization of the annual cost and greenhouse impact related to the supply of natural gas and electricity of an urban microgrid through the installation of components as renewable energy sources, energy storage units and converters. As input parameters of the optimization model, the energy demand of a medium density urban district was estimated, while average costs and emissions of equipment were collected in market reports and literature. The outputs of the model are the optimal size and the schedule of each component. Moreover, optimization analysis was carried out for two different scenarios, comparing Italian and Vietnamese energy system cost and environmen…

A distributed minimum losses optimal power flow for islanded microgrids

2017

Abstract In this work, the minimum losses optimal power dispatch problem for islanded microgrids with distributed energy resources (DER) is solved by means of a distributed heuristic approach. Optimal power management is performed almost in real time, with a predefined schedule, i.e. every 5 min, and the solution is applied to generators when the current operating solution violates voltage or current constraints or when the current configuration produces too large power losses. The operating point of both inverter-interfaced generation units as well as rotating production systems can be modified simply using local information. The latter are voltage measurements and power injections or load…

A Review of Nanogrid Technologies for Forming Reliable Residential Grid

2020

Nanogrid is a scale down version of Microgrid. Nanogrid (NG) forms the residential grid with the sources like solar PV, diesel generator, fuel cell and battery based energy storage as a backup for supporting autonomous operation of NG. This paper is focused on portraying the importance of NG for rural electrification of India. The source-load coordination in the NG will ensure the optimal power flow in the grid. This paper has reviewed two most important control techniques i.e. centralized and decentralized for ensuring source-load coordination in the NG. Interfacing converters are the important constituents of NG to dispatch the power from intermittent renewable energy sources to load. Dep…

Assessment of energy management technique for achieving the sustainable voltage level during grid outage of hydro generator interfaced DC Micro-Grid

2021

Abstract An appropriate energy management scheme is needed for the reliable and sustainable operation of DC microgrid. The energy management scheme of DC microgrid (MG) is mainly controlled by main energy resource of MG. Main energy resource needs to be dispatchable unit for forming the reference voltage within DC MG. In this work, a micro hydro generator (MHG) is considered as a dispatchable source for forming the sustainable voltage level of DC MG operating under the abnormal condition. In this work, the abnormality refers to the outage of solar PV due to intermittency during fluctuating load condition. But, due to mechanical time constant of MHG and rate of charging/discharging current l…

Modeling and Performance Assessment of the Split-Pi Used as a Storage Converter in All the Possible DC Microgrid Scenarios. Part I: Theoretical Analy…

2021

The integration of an electrical storage system (ESS) into a DC microgrid using a bidirectional DC/DC converter provides substantial benefits but requires careful design. Among such converter topologies, the Split-pi converter presents several merits at the cost of non-isolated operation. However, the few works in the literature on the Split-pi presented only closed-loop control with a single control loop; furthermore, they neglected the reactive components’ parasitic resistances and did not perform any experimental validation. This work aimed at investigating the use of the Split-pi converter as a power interface between an ESS and a DC microgrid. Five typical microgrid scenarios are prese…

A Simulation Analysis for Assessing the Reliability of AC/DC Hybrid Microgrids - Part I: Underground Station and Car Parking

2021

This paper reports the results of a simulation study with the aim of evaluating the capability of two portions of a hybrid AC/DC MV/LV network of maintaining their operation in off-grid mode during the loss of the main AC grid due to a failure. In particular, the study aims to verify, in the case of islanded operation of the two microgrids, the continuity of the electricity service by exploiting the local generation plants, Energy Storage Systems (ESSs), and other flexible resources managed by suitable algorithms in different energy scenarios. The analysis was carried out considering two microgrids: an underground station and a car parking with Electric Vehicles (EVs). For assessing the per…