scholarly journals Load Areas in Radial Unbalanced Distribution Systems

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3030 ◽  
Author(s):  
Giovanni M. Casolino ◽  
Arturo Losi

The demand becoming flexible is a requirement for the full exploitation of renewable energy sources. Aggregation may foster the provision of flexibility by small-scale providers connected to distribution grids, since it allows offering significant flexibility volumes to the market. The aggregation of flexibility providers is carried out by the aggregator, a new market role and possibly a new market player. Location information of individual flexibility providers is necessary for both the aggregator and the system operators, in particular, the Distribution System Operator (DSO). For the former, information should allow treating a high number of individual flexibility providers as a single provider to offer significant flexibility volumes to the markets; for the latter, the information should ensure an adequate visibility of the connection of the individual providers to the grid. In the paper, the concept of Load Area (LA) is recalled, which combines the needs of location information of the aggregator and of the DSO. A method for the identification and modeling of LAs for the general case of unbalanced radial systems is proposed. The results of the methods’ application to two studied unbalanced networks are presented, showing the effectiveness and viability of the proposed approach.

2021 ◽  
Vol 13 (7) ◽  
pp. 3636
Author(s):  
Balázs Kulcsár ◽  
Tamás Mankovits ◽  
Piroska Gyöngyi Ailer

In addition to the examination of electric power from local renewables, this study has sought the answer to the question of what proportion of vehicles are fueled by environmentally friendly energy saving technologies in the vehicle fleets of Hungarian settlements. Further, the study attempts to shed light on the self-sufficiency of Hungarian settlements with respect to the electricity and transport segments. In our assessments, the performance of small-scale household power plants (SSHPPs) utilizing local renewable energy sources, and small-scale power plants with installed capacities under 0.5 MW, was taken into account, as were the proportions of vehicles operating with partly or completely clean energy sources in the vehicle fleets of the individual settlements. Finally, the composition of the vehicle fleet has been examined in the light of the quantities of renewable electricity generated in the individual settlements, in order to consider whether these settlements are capable of covering the energy needs of their vehicle stocks from local sources. In the light of the results, the changes generated by the incentives and investments introduced over the past ten years can be established and subsequently, the energy policy needs in the future can be assessed. Our study has incorporated energy geography and settlement geography aspects.


This Paper presents a control strategy of the grid interconnected inverter Renewable Energy Sources (RES). This system can achieve the maximum benefits from these grid interconnected inverter when installed in 3-phase 4-wire distribution system. Increasing electrification of daily life causes growing electricity consumption and the rising number of sensitive or critical loads demand for high quality electricity. One of the main problems facing today is that related with the transmission and distribution of electricity. Due to the rapid increase in global energy consumption and the diminishing of fossil fuels, the customer demand for new generation capacities and efficient energy production, delivery and utilization keeps rising. Utilizing distributed generation, renewable energy and energy storage can potentially solve problems as energy shortage. With the increase in load demand, the Renewable Energy Sources (RES) are increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. The inverter can perform as a multi function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.


Energies ◽  
2013 ◽  
Vol 6 (2) ◽  
pp. 634-645 ◽  
Author(s):  
Nicolae Golovanov ◽  
George Lazaroiu ◽  
Mariacristina Roscia ◽  
Dario Zaninelli

Author(s):  
Lazhar Bougouffa ◽  
Abdelaziz Chaghi

<p>The use of Distributed Renewable Energy Sources in the electrical network has expanded greatly. But, integration of these resources into distribution systems caused more problems in protection related issues such as mis-coordination, and changes the direction and value of fault currents. When connecting new D-RES to electrical power distribution networks, it is required to re-coordinate Directional Over-CurrentRelays (DOC-Relays) to ensure the continuity of the power transmission when the short circuits take place. This work presented a Particle Swarm Optimization (PSO) algorithm to determine two independent variables called Pickup current (Ip) and Time Dial Setting (TDS) for optimal setting of relays. From analysis result, the impacts of RES location in the distribution system on DOCRs had been observed on the optimal relays settings</p>


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 471
Author(s):  
Eman S. Ali ◽  
Ragab A. El-Sehiemy ◽  
Adel A. Abou El-Ela ◽  
Karar Mahmoud ◽  
Matti Lehtonen ◽  
...  

The output generations of renewable energy sources (RES) depend basically on climatic conditions, which are the main reason for their uncertain nature. As a result, the performance and security of distribution systems can be significantly worsened with high RES penetration. To address these issues, an analytical study was carried out by considering different penetration strategies for RES in the radial distribution system. Moreover, a bi-stage procedure was proposed for optimal planning of RES penetration. The first stage was concerned with calculating the optimal RES locations and sites. This stage aimed to minimize the voltage variations in the distribution system. In turn, the second stage was concerned with obtaining the optimal setting of the voltage control devices to improve the voltage profile. The multi-objective cat swarm optimization (MO-CSO) algorithm was proposed to solve the bi-stages optimization problems for enhancing the distribution system performance. Furthermore, the impact of the RES penetration level and their uncertainty on a distribution system voltage were studied. The proposed method was tested on the IEEE 34-bus unbalanced distribution test system, which was analyzed using backward/forward sweep power flow for unbalanced radial distribution systems. The proposed method provided satisfactory results for increasing the penetration level of RES in unbalanced distribution networks.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4270
Author(s):  
Gianpiero Colangelo ◽  
Gianluigi Spirto ◽  
Marco Milanese ◽  
Arturo de Risi

In the last years, a change in the power generation paradigm has been promoted by the increasing use of renewable energy sources combined with the need to reduce CO2 emissions. Small and distributed power generators are preferred to the classical centralized and sizeable ones. Accordingly, this fact led to a new way to think and design distributions grids. One of the challenges is to handle bidirectional power flow at the distribution substations transformer from and to the national transportation grid. The aim of this paper is to review and analyze the different mathematical methods to design the architecture of a distribution grid and the state of the art of the technologies used to produce and eventually store or convert, in different energy carriers, electricity produced by renewable energy sources, coping with the aleatory of these sources.


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