scholarly journals A Review of Low-Voltage Renewable Microgrids: Generation Forecasting and Demand-Side Management Strategies

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2093
Author(s):  
Miguel Aybar-Mejía ◽  
Junior Villanueva ◽  
Deyslen Mariano-Hernández ◽  
Félix Santos ◽  
Angel Molina-Garcia

It is expected that distribution power systems will soon be able to connect a variety of microgrids from residential, commercial, and industrial users, and thus integrate a variety of  distributed generation technologies, mainly renewable energy sources to supply their demands. Indeed, some authors affirm that distribution networks will propose significant changes as a consequence of this massive integration of microgrids at the distribution level. Under this scenario, the control of distributed generation inverters, demand management systems, renewable resource forecasting, and demand predictions will allow better integration of such microgrid clusters to decongest power systems. This paper presents a review of  microgrids connected at distribution networks and the solutions that facilitate their integration into such distribution network level, such as demand management systems, renewable resource forecasting, and demand predictions. Recent contributions focused on the application of microgrids in Low-Voltage distribution networks are also analyzed and reviewed in detail. In addition, this paper provides a critical review of the most relevant challenges currently facing electrical distribution networks, with an explicit focus on the massive interconnection of electrical microgrids and the future with relevant renewable energy source integration.

2021 ◽  
Author(s):  
Rachel Koh ◽  
Jordan Kern ◽  
AFM Kamal Chowdhury ◽  
Stefano Galelli

<p>Multi-sector modelling frameworks are fundamental platforms for exploring the complex interactions between the water and energy sectors. While acknowledging the pivotal role of hydropower within the energy system, it is essential to understand the feedback mechanisms between power and water systems to guide the design of hydropower operations and enhance water-energy management strategies. With this in mind, we developed a modelling framework hinged on a bidirectional coupling between water and power system models. We simulate the constraints imposed by water availability on grid operations as well as the feedback between the state of the energy and water systems. For example, the framework explicitly accounts for conditions of hydropower oversupply, during which part of the water could be stored in reservoirs or allocated to other sectors. The flexibility added to the system gives operators control over desired reservoirs, and allows the system to exploit the benefits warranted by a more efficient use of renewable energy. We evaluate the framework on a real-world case study based on the Cambodian grid, which relies on hydro, solar, and thermoelectric resources. In our analysis, we demonstrate that managing hydropower reservoirs with the feedback mechanism in mind allows us to improve system’s performance—evaluated in terms of power production costs and CO<sub>2</sub> emissions. Overall, our work contributes a novel modelling tool for climate-water-energy nexus studies, working towards an optimal integration of hydropower and other renewable energy sources into power systems.</p>


2021 ◽  
Vol 2 (43) ◽  
pp. 41-47
Author(s):  
Oleg A. Roshchin ◽  

The features of Russia is the low population density on huge, poorly developed lands in terms of production. About 20 million people live in the territory where there is no centralized power supply, power supply is organized on generating systems running on imported fuel. (Research purpose) The research purpose is in studying the prospects for the development of microgrids based on the use of alternative energy generating systems of renewable energy sources using a micro-gas turbine plant as the base generator, which is the source of the reference voltage of microgrid based on single-wire resonant distribution networks of a new generation in Russia. (Materials and methods) The article presents the prospects for the development of microgrids based on material taken from open sources. Authors applied the methods of scientific analysis of events, facts, materials, and conclusions. (Results and discussions) The article shows that the world energy system evolutionarily enters a new fourth stage of fundamental transformation, called the "Energy Transition". The creation of microgrids based on renewable energy sources with a basic micro-gas turbine unit and single-wire resonant distribution networks of a new generation is an indisputable proof of this energy transition. (Conclusions) In many countries of the world, there is an increase in the share of distributed generation based on renewable energy sources, the introduction of new centralized generation capacities is reduced, investments in the construction of large power plants and new high-voltage transmission lines are reduced due to the development of distributed generation. Distributed generation contributes to the rapid expansion of electricity production without the need for additional development of the power grid infrastructure.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3610
Author(s):  
Dawid Buła ◽  
Dariusz Grabowski ◽  
Andrzej Lange ◽  
Marcin Maciążek ◽  
Marian Pasko

Network working conditions are influenced noticeably by the connection of renewable energy sources to distribution networks. This becomes more and more important due to the increase in renewable energy source penetration over the last few years. This in turn can lead to a mass effect. As a result, the classical open network model with simple unidirectional direction of energy flow has been replaced with an active model that includes many local energy sources. This paper deals with the analysis of long- and short-term changes in power and energy generated by three types of renewable energy sources with similar rated power and which operate in the same region (i.e., located no more than tens of kilometers away). The obtained results can be a starting point for a broader evaluation of the influence of renewable energy sources on power quality in power systems, which can be both positive (supply reliability) and negative (voltage fluctuations and higher harmonics in current and voltage waveforms). It is important not only to correctly place but also to assure the diversity of such sources as it has been confirmed by the source variability coefficient. The long-term analysis allows us also to estimate the annual repeatability of energy production and, furthermore, the profitability of investment in renewable sources in a given region.


2019 ◽  
Vol 11 (14) ◽  
pp. 3839 ◽  
Author(s):  
Makbul A.M. Ramli ◽  
H.R.E.H. Bouchekara ◽  
Abdulsalam S. Alghamdi

Substituting a single large power grid into various manageable microgrids is the emerging form for maintaining power systems. A microgrid is usually comprised of small units of renewable energy sources, battery storage, combined heat and power (CHP) plants and most importantly, an energy management system (EMS). An EMS is responsible for the core functioning of a microgrid, which includes establishing continuous and reliable communication among all distributed generation (DG) units and ensuring well-coordinated activities. This research focuses on improving the performance of EMS. The problem at hand is the optimal scheduling of the generation units and battery storage in a microgrid. Therefore, EMS should ensure that the power is shared among different sources following an imposed scenario to meet the load requirements, while the operational costs of the microgrid are kept as low as possible. This problem is formulated as an optimization problem. To solve this problem, this research proposes an enhanced version of the most valuable player algorithm (MVPA) which is a new metaheuristic optimization algorithm, inspired by actual sporting events. The obtained results are compared with numerous well-known optimization algorithms to validate the efficiency of the proposed EMS.


Processes ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 34 ◽  
Author(s):  
Shijie Cui ◽  
Peng Zeng ◽  
Chunhe Song ◽  
Zhongfeng Wang

With the decentralization of the electricity market and the plea for a carbon-neutral ecosystem, more and more distributed generation (DG) has been incorporated in the power distribution grid, which is then known as active distribution network (ADN). The addition of DGs causes numerous control and protection confronts to the traditional distribution network. For instance, two-way power flow, small fault current, persistent fluctuation of generation and demand, and uncertainty of renewable energy sources (RESs). These problems are more challenging when the distribution network hosts many converter-coupled DGs. Hence, the traditional protection schemes and relaying methods are inadequate to protect ADNs against short-circuit faults and disturbances. We propose a robust communication-assisted fault protection technique for safely operating ADNs with high penetration of converter-coupled DGs. The proposed technique is realizable by employing digital relays available in the recent market and it aims to protect low-voltage (LV) ADNs. It also includes secondary protection that can be enabled when the communication facility or protection equipment fails to operate. In addition, this study provides the detail configuration of the digital relay that enables the devised protection technique. Several enhancements are derived, as alternative technique for the traditional overcurrent protection approach, to detect small fault current and high-impedance fault (HIF). A number of simulations are performed with the complete model of a real ADN, in Shenyang, China, employing the PSCAD software platform. Various cases, fault types and locations are considered for verifying the efficacy of the devised technique and the enabling digital relay. The obtained simulation findings verify the proposed protection technique is effective and reliable in protecting ADNs against various fault types that can occur at different locations.


2017 ◽  
Vol 30 (2) ◽  
pp. 145-160
Author(s):  
Augustine Egwebe ◽  
Meghdad Fazeli ◽  
Petar Igic ◽  
Paul Holland

This paper explores and discusses various design considerations for inverter-based systems. Different load sharing techniques are presented for the integration of renewable energy sources within islanded microgrids. In off-grid connection, renewable energy sources are often configured to share power based on their rated capacity. This paper explores both conventional and dynamic load sharing interaction between distributed generation units, both in an inductive (high voltage) and resistive (low voltage) networks. Load sharing based on the proper design of virtual impedance is also reviewed.


Author(s):  
Heliasadat Hosseinian ◽  
Hossein Shahinzadeh ◽  
Gevork B. Gharehpetian ◽  
Zohreh Azani ◽  
Mahdi Shaneh

Nowadays, unlike depleting fossil fuel resources, the integration of different types of renewable energy, as distributed generation sources, into power systems is accelerated and the technological development in this area is evolving at a frantic pace. Thus, inappropriate use of them will be irrecoverably detrimental. The power industry will reach a turning point in the pervasiveness of these infinite energy sources by three factors. Climate changes due to greenhouse gas accumulation in the atmosphere; increased demand for energy consumption all over the world, especially after the genesis of Bitcoin and base cryptocurrencies; and establishing a comprehensive perspective for the future of renewable energy. The increase in the pervasiveness of renewable energy sources in small-scale brings up new challenges for the power system operators to manage an abundant number of small-scale generation sources, called microsources. The current structure of banking systems is unable to handle such massive and high-frequency transactions. Thus the incorporation of cryptocurrencies is inevitable. In addition, by utilization of IoT-enabled devices, a large body of data will be produced must be securely transferred, stored, processed, and managed in order to boost the observability, controllability, and the level of autonomy of the smart power systems. Then the appropriate controlling measures must be performed through control signals in order to serve the loads in a stable, uninterruptible, reliable, and secure way. The data acquires from IoT devices must be analyzed using artificial intelligence methods such as big data techniques, data mining, machine learning, etc. with a scant delay or almost real-time. These measures are the controversial issues of modern power systems, which are yet a matter of debate. This study delves into the aforementioned challenges and opportunities, and the corresponding solutions for the incorporation of IoT and blockchain in power systems, particularly in the distribution level and residential section, are addressed. In the last section, the role of IoT in smart buildings and smart homes, especially for energy hubs schemes and the management of residential electric vehicle supply equipment is concisely discussed.


Author(s):  
Yuri Bulatov ◽  
◽  
Andrey Kryukov ◽  
Aleksandr Cherepanov ◽  
◽  
...  

Decentralization of electricity generation based on distributed generation plants is an important segment of the new technology platform for the power industry. On the basis of this approach, significant positive effects can be obtained, which consist in reducing financial costs of energy supply, increasing the uninterrupted power supply, improving the quality of electricity and stimulating the use of renewable energy sources. Effective use of distributed generation in electric power systems requires the development of methods and tools that provide coordinated management of normal, emergency and post-emergency modes. Of particular relevance is the problem of determining the limit operating modes of networks, at the nodal points of which relatively low power generators are connected. In some situations, for example, when using small hydraulic stations, groups of such generators can be located at significant distances for 6-10-20 kV distribution networks from consumption centers. In this case there will be a noticeable limitation of the regions of static aperiodic stability. The article presents the results of developments aimed at implementing methods for determining the limit operating modes by static aperiodic stability in networks with distributed generation plants. The proposed approach is based on the limit modes equations which provide the formation of effective algorithms for the operational finding of points belonging to the boundaries of stability regions. The results of the construction of the indicated areas for a 6 kV electric network with distributed generation plants based on low-power hydraulic stations are presented. Additionally, the transient processes in the studied electric power system were simulated in the Matlab system for various space points of the controlled mode parameters.


Author(s):  
Dimosthenis Verginadis ◽  
Athanasios Karlis

Background: The scope of this paper is to study the energy trading in microgrids. Microgrids are low voltage or medium voltage distribution networks, which consist of energy storage systems, electric loads, e.g. electric vehicles and Renewable Energy Sources (RES). Methods: Legacy energy grids are being transformed by the introduction of small to medium sized individual or cooperative, mostly RES invested energy producers and prosumers. Electric vehicles penetrate the market and modern power grids integrate them as ancillary services providers when there are peak domestic loads, as well as in order to balance grid voltage aiming to increase system reliability, compensating for renewable energy sources’ intermittency and volatility in energy production. Results: An elaborate management algorithm is proposed in this paper, to balance demand and local renewable energy sources microgrid supply. Conclusion: Finally, the results of simulations of different scenarios, including economic parameters and proposals for future research are presented.


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