Challenges, advances and future directions in protection of hybrid AC/DC microgrids

Hybrid microgrids which consist of AC and DC subgrids interconnected by power electronic interfaces have attracted much attention in recent years. They not only can integrate the main benefits of both AC and DC configurations, but also can reduce the number of converters in connection of Distributed Generation (DG) sources, Energy Storage Systems (ESSs) and loads to AC or DC buses. In this paper, the structure of hybrid microgrids is discussed, and then a broad overview of the available protection devices and approaches for AC and DC subgrids is presented. After description, analysis and classification of the existing schemes, some research directions including communication infrastructures, combined control and protection schemes, and promising devices for the realisation of future hybrid AC/DC microgrids are pointed out

Communication improvements for intelligent systems in microgrids - Part I & II

This paper proposes the best architecture for intelligent microgrid applications based on latency, QoS, bandwidth and capital cost, to improve control and operation. In addition, the fundamentals of communications and control strategies for intelligent microgrids and electric vehicles are described. The results show that communication technology affects the performance of control applications and the smartness of the grid, which causes poor quality of service.CONACYT – Consejo Nacional de Ciencia y Tecnologí

Recent Developments and Challenges on AC Microgrids Fault Detection and Protection Systems–A Review

The protection of AC microgrids (MGs) is an issue of paramount importance to ensure their reliable and safe operation. Designing reliable protection mechanism, however, is not a trivial task, as many practical issues need to be considered. The operation mode of MGs, which can be grid-connected or islanded, employed control strategy and practical limitations of the power electronic converters that are utilized to interface renewable energy sources and the grid, are some of the practical constraints that make fault detection, classification, and coordination in MGs different from legacy grid protection. This article aims to present the state-of-the-art of the latest research and developments, including the challenges and issues in the field of AC MG protection. A broad overview of the available fault detection, fault classification, and fault location techniques for AC MG protection and coordination are presented. Moreover, the available methods are classified, and their advantages and disadvantages are discussed

Communication in microgrids and virtual power plants

One of the cornerstones of the steady operation of microgrids and virtual power plants as building blocks for smart grid is the communication system, which is the main objective for evaluation and research in this thesis. The given project investigates the most widespread communication protocols along with IEC 61850 standard for substations automation applied in smart grids. Based on the presented analysis for communication technologies and protocols the appropriate communication solution for the laboratory microgrid at UiT – The Arctic University of Norway (Campus Narvik) is suggested and implemente

Microgrid architecture evaluation for small and medium size industries

Os clientes industriais procuram formas de reduzir o consumo energético e a sua pegada ecológica através de medidas de eficiência energética e fontes de energia limpa, como sistemas de geração de energia solar e eólica. Contrariamente às grandes empresas industriais, pode ser difícil para as pequenas indústrias melhorar a sua eficiência energética devido a condições financeiras limitadas e à falta de consciencialização para as aplicações económicas das fontes de energia renováveis. No entanto, o aumento da integração de fontes de energia limpas no setor industrial fez com que as microrredes se tornassem uma mais valia para atenuar o impacto ambiental associado ao uso de combustíveis fósseis para geração de energia. As microrredes contribuem para um aumento significativo de fiabilidade e qualidade da energia fornecida sem quaisquer distúrbios e interrupções. Estes benefícios só podem ser assegurados com um sistema de proteção que seja capaz de operar efetivamente durante qualquer condição anormal. Esta dissertação aborda vários aspetos que visam auxiliar no estudo de arquiteturas de microrredes industriais. Este trabalho apresenta uma visão geral das tecnologias de comunicação e fontes de energia mais comuns para microrredes, assim como estratégias de controlo para conversores de potência e outros aspectos de controlo, como o método de droop control e o controlo hierárquico. Além disso, são também abordados vários métodos de proteção que podem ser implementados em microrredes, incluindo dispositivos de proteção e esquemas de ligação à terra frequentemente usados em sistemas de distribuição de baixa tensão. Finalmente, é apresentado um estudo de caso para observar como uma implementação centralizada e descentralizada de fontes de energia afeta o desempenho de uma pequena microrrede industrial em diferentes cenários e eventos de falha.Instituto Politécnico de Toma

New High-Speed Directional Relay Based on Wireless Sensor Network for Smart Grid Protection

The production of energy from water represents large amounts of clean and renewable energy. However, only 30% of this energy has been developed so far. Hydropower, particularly hydropower plants, is not only environmentally friendly but also economical, and operates more efficiently than any other renewable energy system. Hydropower plants are largely automated and have relatively low operating costs. The main components of the power system must be continuously monitored and protected to maintain the quality and reliability of the power source. This task is provided by the data collection, monitoring and protection system. Turbines must be protected not only by short circuits but also by abnormal conditions. The proposed protection has been designed to avoid damaging the original power (motor or turbine), this usually happens when the generator fails, and the machine operates as a synchronous motor connected to the power system. In this case, the generator becomes an active load, causing a rise in temperature and severe damage to the main turbine, and hence it becomes a need to quickly detect these conditions. This study proposes a new controller for Neuro-Fuzzy to prevent reverse power flow and to keep the quality and reliability of supply. Fuzzy system network has attracted various scientific and engineering researchers. The new feature of this work is to adjust the membership function as a reverse mechanism derived of the Fuzzy Logic Controller. The smart meter network is the basis of the smart grid. In this study, smart grid meters were implemented using ZigBee technology based on wireless sensor networks. The ZigBee network of wireless sensors due to its low battery, low power consumption, become more useful than other wireless communication systems to provide a high-performance measurement. This study shows the ZigBee network using the OPNET simulation. Depending on the performance, parameters were analysed to understand the operating characteristics of the star, tree, and mesh

An Adaptive Protection for Radial AC Microgrid Using IEC 61850 Communication Standard : Algorithm Proposal Using Offline Simulations

The IEC 61850 communication standard is getting popular for application in electric power substation automation. This paper focuses on the potential application of the IEC 61850 generic object-oriented substation event (GOOSE) protocol in the AC microgrid for adaptive protection. The focus of the paper is to utilize the existing low-voltage ride through characteristic of distributed generators (DGs) with a reactive power supply during faults and communication between intelligent electronic devices (IEDs) at different locations for adaptive overcurrent protection. The adaptive overcurrent IEDs detect the faults with two different preplanned settings groups: lower settings for the islanded mode and higher settings for the grid-connected mode considering limited fault contributions from the converter-based DGs. Setting groups are changed to lower values quickly using the circuit breaker status signal (XCBR) after loss-of-mains, loss-of-DG or islanding is detected. The methods of fault detection and isolation for two different kinds of communication-based IEDs (adaptive/nonadaptive) are explained for three-phase faults at two different locations. The communication-based IEDs take decisions in a decentralized manner, using information about the circuit breaker status, fault detection and current magnitude comparison signals obtained from other IEDs. However, the developed algorithm can also be implemented with the centralized system. An adaptive overcurrent protection algorithm was evaluated with PSCAD (Power Systems Computer Aided Design) simulations, and results were found to be effective for the considered fault cases.© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed