Search results for " Microgrids"
showing 10 items of 21 documents
Robust Multi-Objective Optimal dispatch of Distributed Energy Resources in Micro-Grids
2011
Modern distribution systems are implemented through micro grids: small power networks where generation is close to consumption and ICT supports the coordinated management of the different energy resources. In such systems, the central control unit manages energy dispatch from the different sources according to different criteria (technical, economical and environmental) and takes care of tertiary regulation. Such optimization for the tertiary regulation is performed with a time interval that typically is of 24 hours. This is due to the fact that it is necessary to take into account the charge and discharge cycles of storage systems. On the other hand, such long time leads to large errors in…
Optimal Set Points Regulation of Distributed Generation Units in Micro-grids under Islanded Operation
2010
The present work studies the problem of optimizing the power production levels of dispersed generation units in islanded microgrids. The problem is intrinsically multi-objective with non linear objectives and constraints, thus the solution approach is based on evolutionary optimization and uses the Non dominated Sorting Genetic Algorithm II. The objectives are calculated based on the solution of the load flow problem. The latter problem is more complicated when in the considered system a physical node with a sufficiently large production capability is not available, because all the generation node of the systems have similar and limited generation capability. In this paper, the issue has be…
Frequency constrained optimal Power Flow based on Glow-worm Swarm Optimization in Islanded Microgrids
2015
This work presents an application of a swarm optimization method to solve the optimal power flow problem taking into account the constraints of frequency and line ampacity in three-phase islanded Microgrids. Each generation unit is equipped with a Power Electronics Interface. In the considered formulation, the droop control parameters are considered as variables to be adjusted by a higher control level, while the frequency is kept in rated bounds. Another typical constraint for OPF formulation, the max ampacity of each line, is also considered. Two case studies with different dimensions and electrical features have been considered and the obtained results show the efficiency of the proposed…
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…
Fault Tolerant Ancillary Function of Power Converters in Distributed Generation Power System within a Microgrid Structure
2013
Distributed generation (DG) is deeply changing the existing distribution networks which become very sophisticated and complex incorporating both active and passive equipment. The simplification of their management can be obtained assuming a structure with small networks, namely, microgrids, reproducing, in a smaller scale, the structure of large networks including production, transmission, and distribution of the electrical energy. Power converters in distributed generation systems carry on some different ancillary functions as, for example, grid synchronization, islanding detection, fault ride through, and so on. In view of an optimal utilization of the generated electrical power, fault to…
Dynamic Control of Static Converters for the Transition from Grid-on to Grid-off Operation of AC/DC Microgrids
2022
In this paper, specific control logics defined for generators, controllable loads and electric energy storage systems are illustrated in order to improve the reliability of AC/DC hybrid microgrids in their grid-off operation following failure events such as short-circuits, line breaks, sudden disconnections of generating units or loads, etc. After defining specific control schemes, these were modelled in a digital environment and finally tested with dynamic simulations. Finally, the paper highlights the role of virtual synchronous machine control for the self-healing capacity of islanded hybrid microgrids.
Effects of Demand Side Management on the Operation of an Isolated LV Microgrids
2019
The work presents the results of a study regarding the impact of Demand Side Management actions on flexible loads distributed at the domestic end-users' facilities in an isolated low voltage microgrid. Aim of the research study is to evaluate how the implementation of local control actions on the end-user's side can impact on the operation of the isolated microgrid. The Demand Side Management is applied by each domestic user to optimize the operation of its own resources following well-defined operative steps. The study is carried out implementing a suitable model of the microgrid in Neplan environment, while the daily controlled load profiles of the end-users are evaluated using the Montec…
A stochastic approach for self-healing capability evaluation in active islanded AC/DC hybrid microgrids
2023
This paper aims to implement a resilience assessment in AC/DC hybrid microgrids using a stochastic simulation approach. Self-healing measures including load shedding, control of distributed generation and flexible devices, like Energy Storage Systems (ESS) and Electrical Vehicles (EVs), are simulated to enable AC/DC hybrid microgrids to supply critical loads in islanded mode, assuming a disconnection of these microgrids from the main AC grid due to a fault. To perform this analysis, a two-stage process is proposed: first, a Monte-Carlo simulation-based stochastic approach is adopted to generate samples to simulate intermittent loads, power generation from Renewable Energy Sources (RESs), an…
Online optimization of a multi-conversion-level DC home microgrid for system efficiency enhancement
2017
In this paper, an on-line management system for the optimal efficiency operation of a multi-bus DC home distribution system is proposed. The operation of the system is discussed with reference to a distribution system with two conversion stages and three voltage levels. In each of the conversion stages, three paralleled DC/DC converters are implemented. A Genetic Algorithm performs the on-line optimization of the DC network’s global efficiency, generating the optimal current sharing ratios of the concurrent power converters. The overall DC/DC conversion system including the optimization section is modelled using MATLAB/Simulink. Thanks to the implemented online algorithm, considering …
A New Meta-Heuristic Multi-Objective Approach For Optimal Dispatch of Dispersed and Renewable Generating Units in Power Distribution Systems
2011
The application of stochastic methods in engineering research and optimization has been increasing over the past few decades. Ant Colony Optimization, in particular, has been attracting growing attention as a promising approach both in discrete and continuous domains. The present work proposes a multi-objective Ant Colony Optimization for continuous domains showing good convergence properties and uniform coverage of the non-dominated front. These properties have been proved both with mathematical test functions and with a complex real world problem. Besides the second part of the chapter presents the application of the new algorithm to the problem of optimal dispatch of dispersed power gene…