scholarly journals A Control Method for Balancing the SoC of Distributed Batteries in Islanded Converter-Interfaced Microgrids

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Spyros I. Gkavanoudis ◽  
Konstantinos O. Oureilidis ◽  
Georgios C. Kryonidis ◽  
Charis S. Demoulias
Keyword(s):  
Distributed Generation ◽  
Control Method ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Intermediate Frequency ◽  
Nonlinear Loads ◽  
Time Duration ◽  
Detailed Simulation ◽  
Filter Operation ◽  
A Current

In a low-voltage islanded microgrid powered by renewable energy sources, the energy storage systems (ESSs) are considered necessary, in order to maintain the power balance. Since a microgrid can be composed of several distributed ESSs (DESSs), a coordinated control of their state-of-charge (SoC) should be implemented, ensuring the prolonged lifespan. This paper proposes a new decentralized control method for balancing the SoC of DESSs in islanded microgrids, without physical communication. Each DESS injects a current distortion at 175 Hz, when its SoC changes by 10%. This distortion is recognized by every DESS, through a phase-locked loop (PLL). In order to distinguish the origin of the distortion, each DESS injects a distortion of different time duration. This intermediate frequency has been selected in order to avoid the concurrence with the usual harmonics. The DESSs take advantage of this information and inject a current proportional to the SoC. Implementing this strategy, a comparable number of charging/discharging cycles for each DESS are achieved. Furthermore, an active filter operation, implemented in the dq rotating frame for each individual harmonic, is integrated in the control of the distributed generation units, supplying nonlinear loads with high-quality voltage. The effectiveness of this method is verified by detailed simulation results.

Control of Quasi-Z Source Inverter with Super Capacitor under Unbalanced Grid Fault Conditions

2013 ◽  
Vol 291-294 ◽  
pp. 2124-2131
Author(s):  
Feng Lin Li ◽  
Shu Ju Hu ◽  
Ling Ling Wang
Keyword(s):  
Reference Frames ◽  
Control Method ◽  
Low Voltage ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Super Capacitor ◽  
Loop Control ◽  
Control Scheme ◽  
Unbalanced Grid ◽  
Generation Unit

The quasi-Z-source inverter (qZSI) has some unique advantages and is suitable for renewable energy sources such as solar and wind generation system. In order to make the inverter have the ride-through ability and the current into the grid symmetrical when unbalanced grid faults occur, the topology of qZSI with super capacitor substituting the low voltage capacitor and the unbalance control strategy were proposed. With a super capacitor the system can balance and smooth the power between the generation unit and grid, also the current injected into the grid can be symmetrical through the unbalance control method. The circuit of the new topology and the mathematical model of the three-phase converter under grid voltage unbalance conditions have been analyzed. And then, closed-loop control scheme for the proposed system is used to control the power flow of generation unit, grid and super capacitor in this system, also unbalance control strategies in positive (dq) + and negative (dq) – reference frames have been implemented in the grid-connected qZSI system to make the current into the grid symmetrical during the grid fault. The operating mode during unbalanced grid fault is simulated in MATLAB/Simulink, and the simulation results are presented to verify the theoretical analysis and the control scheme.

scholarly journals Load sharing methods for inverter-based systems in islanded microgrids: A review

2017 ◽  
Vol 30 (2) ◽  
pp. 145-160
Author(s):  
Augustine Egwebe ◽  
Meghdad Fazeli ◽  
Petar Igic ◽  
Paul Holland
Keyword(s):  
Renewable Energy ◽  
Distributed Generation ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Load Sharing ◽  
Energy Sources ◽  
Grid Connection ◽  
Proper Design ◽  
Dynamic Load Sharing ◽  
Virtual Impedance

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.

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
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Distributed Generation ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Demand Management ◽  
Management Strategies ◽  
Renewable Resource ◽  
Distribution Networks ◽  
Management Systems

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.

scholarly journals Current Harmonics Reduction In Microgrids Using Dual Interfacing Converters

2021 ◽  
Vol 12 (2) ◽  
pp. 1647-1654
Author(s):  
Venkatesh E , Et. al.
Keyword(s):  
Distributed Generation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Control Technique ◽  
Test Results ◽  
Nonlinear Loads ◽  
Nonlinear Load ◽  
Current Harmonics ◽  
The Matrix ◽  
Over The Top

The Growing Installation of Distributed Generation (DG) units in low voltage conveyance frameworks has promoted the idea of nonlinear load symphonious current remuneration utilizing multi-utilitarian DG interfacing converters. In appropriation frameworks, the load has been an unexpected increment or diminishes and it resembles as nonlinear loads so the load draw non-sinusoidal flows from the AC mains and causes the load sounds and responsive power, and over the top impartial flows that give contamination in power frameworks. It is investigated in this paper that the pay of neighborhood load symphonious current utilizing a solitary DG interfacing converter may make the intensification of supply voltage sounds touchy loads, especially when the primary framework voltage is profoundly twisted. To address this impediment, in contrast to the activity of customary unified power quality conditioners (UPQC) with arrangement converter, another concurrent stock voltage and matrix current symphonious pay technique is proposed utilizing composed control of two shunt interfacing converters. Through the presentation of staggered control destinations, it is delineated that the proposed framework could ride through voltage unsettling influences and proceed with the power move between the nearby generation and the matrix, while an excellent voltage is kept up for the neighborhood loads. By utilizing this proposed regulator, the lattice voltage stage bolted circle and the identification of the load current and the stockpile voltage music are superfluous for both interfacing converters. In this manner, the computational load of interfacing converters can be fundamentally decreased. Mimicked and test results are caught to approve the exhibition of the proposed geography and the control technique.

Potential Application of HRTSim for Comprehensive Simulation of Large-Scale Power Systems with Distributed Generation

2019 ◽  
Vol 20 (5) ◽  
Author(s):  
Aleksey Suvorov ◽  
Alexander Gusev ◽  
Nikolay Ruban ◽  
Mikhail Andreev ◽  
Alisher Askarov ◽  
...  
Keyword(s):  
Power Systems ◽  
Distributed Generation ◽  
Large Scale ◽  
Design Research ◽  
Renewable Energy Sources ◽  
Test Scheme ◽  
Efficient Design ◽  
Software Complex ◽  
Detailed Simulation ◽  
Digital Hardware

Abstract Currently, the number of distributed generation (DG) objects in the world is growing mainly due to renewable energy sources (RES). However, the integration of a large volume of DG based on RES into existing electric power systems (EPS) is associated with a number of significant problems. For a comprehensive study and solution of these problems, it is necessary to carry out detailed simulation of real EPS, which is not always feasible with the help of existing tools. Therefore, the article proposes the use of an alternative solution – the Hybrid Real-Time Power System Simulator (HRTSim). To confirm the properties and capabilities of the HRTSim, the simulation results of a test scheme obtained using the HRTSim and the widely used digital hardware-software complex RTDS were compared. The results of a comprehensive comparison in both complexes confirmed the adequacy of information about the processes in equipment and EPS as a whole, obtained by the HRTSim. Thus, it is proved that further use the HRTSim as a tool for detailed and adequate simulation of real EPS with DG will provide complete and reliable information about normal and abnormal quasi-steady-state and transient processes, which is necessary for reliable and efficient design, research and subsequent operation of EPS with DG.

scholarly journals Fluctuation Suppression of DC-Link Voltage Using Control of Converters Connected with DC Distributed Generation

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5832
Author(s):  
Sang-Jae Choi ◽  
Sung-Hun Lim
Keyword(s):  
Power Generation ◽  
Distributed Generation ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Voltage Fluctuation ◽  
Voltage Fluctuations ◽  
Dc Voltage ◽  
Low Voltage Ride Through ◽  
Dc Power ◽  
Fault Ride Through

Due to the increase in DC load and DC Power generation, the need for DC power system is emerging. Accordingly, FRT (fault ride through) and LVRT (low voltage ride through), which are related regulations for renewable energy sources, have been enacted, and operation algorithms of each converter are required for this. However, the operation of the converter according to LVRT regulations causes DC voltage fluctuations. In the current study, DC voltage fluctuation is suppressed through converter control of DC-linked battery. The controller was designed from the relational equation between DC voltage and instantaneous power of battery. The pattern of DC voltage fluctuations to the output of the PV (photovoltaic), which is a DC power generation source, was confirmed, and voltage fluctuation suppression was verified by applying the designed converter cooperation algorithm and controller.

Economical Benefits of Integrating Solar Energy Based DG units on an Existing Low Voltage Distribution Network in Pakistan

2021 ◽  
Vol 9 (5) ◽  
pp. 597-601
Keyword(s):  
Distributed Generation ◽  
System Integration ◽  
Low Voltage ◽  
Energy Requirement ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Energy Utilization ◽  
Electricity Production ◽  
Solar Pv ◽  
Pv System

Availability of electrical energy plays a dynamic role in the social and economic development of any country. The energy mix in Pakistan is majorly dependent on the non-renewable energy sources which are imported,which results a short of electricity production while the consumers are facing a load shedding of 10-12h/day. This technological revolution, regulatory environment and changing economic conditions increase theimportance of Distributed Generation. Distributed Generation not only meets the energy requirements of any country but also improves the various issues such as saving in cost, reduction in technical losses, improvement in the power quality, reliability and security, reduction in power losses and environmental concerns to decrease the greenhouse gases. This paper presents the comparison of the energy utilization and its price between the existing low voltage system and the proposed solar PV system integration. It is seen that with the integration of an optimized PV system we will not only meet the energy requirement of our existing system but also inject some amount of energy in access to the national grid. Also a cost to benefit ratio of 2.63 is calculated which means the cost of this modification can be reversed in a time less than 3 years while the normal life of a PV system is taken as 25 years

scholarly journals STUDI PENGARUH TIDAK BEROPERASINYA PLTSa SUWUNG TERHADAP PROFIL TEGANGAN PADA PENYULANG SERANGAN

2018 ◽  
Vol 5 (2) ◽  
pp. 299
Author(s):  
Gede Endrawadi ◽  
I Wayan Sukerayasa ◽  
Wayan Gede Ariastina
Keyword(s):  
Renewable Energy ◽  
Power Plant ◽  
Distributed Generation ◽  
Power Supply ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
Energy Sources ◽  
Voltage Profile ◽  
Medium Voltage

The power plant with renewable energy sources is needed to reduce the pollution. One of this kind is in Bali, that is PLTSa (Garbage Power Plant) Suwung. However, PLTSa Suwung is no longer operating for now. PLTSa Suwung is connected with Serangan feeder, this connection named Distributed Generation. When PLTSa Suwung doesn’t operate, it will affect the Serangan feeder’s voltage profile. The change of voltage profile will be analyzed with EDSA Technical 2000 Service Pack 3.5 software. The research will give five scenarios with different electrical power supply from each scenario. The gap of the voltage profile between scenario 1 (100% power supply from PLTSa) and scenario 5 (0% power suplly from PLTSa) is 0,0079% for medium voltage bus and 0,0062% for low voltage bus. This small gap shows that the connected PLTSa Suwung doesn’t give effect to voltage profile of Serangan feeder.

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