scholarly journals Smart Transformers as Active Interfaces Enabling the Provision of Power-Frequency Regulation Services from Distributed Resources in Hybrid AC/DC Grids

2020 ◽  
Vol 10 (4) ◽  
pp. 1434 ◽  
Author(s):  
Justino Rodrigues ◽  
Carlos Moreira ◽  
João Peças Lopes
Keyword(s):  
Storage System ◽  
Computational Simulation ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Active Power ◽  
Frequency Regulation ◽  
Distributed Resources ◽  
Regulation Services ◽  
Power Frequency ◽  
Pv Generation

Smart Transformers (STs) are being envisioned as a key element for the controllability of distribution networks in a future context of Renewable Energy Source (RES), Energy Storage System (ESS) and Electric Vehicle (EV) massification. Additionally, STs enable the deployment of hybrid AC/DC networks, which offer important advantages in this context. In addition to offering further degrees of controllability, hybrid AC/DC networks are more suited to integrate DC resources such as DC loads, PV generation, ESS and EV chargers. The purpose of the work developed in this paper is to address the feasibility of exploiting STs to actively coordinate a fleet of resources existing in a hybrid AC/DC network supplied by the ST aiming to provide active power-frequency regulation services to the upstream AC grid. The feasibility of the ST to coordinate the resources available in the hybrid distribution AC/DC network in order to provide active power-frequency regulation services is demonstrated in this paper through computational simulation. It is demonstrated that the aforementioned goal can be achieved using droop-based controllers that can modulate controlled variables in the ST.

scholarly journals Using Energy Storage Inverters of Prosumer Installations for Voltage Control in Low-Voltage Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Storage System ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Active Power ◽  
Total Power

The paper includes the analysis of the operation of low-voltage prosumer installation consisting of receivers and electricity sources and equipped with a 3-phase energy storage system. The aim of the storage application is the management of active power within the installation to decrease the total power exchanged with the supplying network and thus reduce energy costs borne by the prosumer. A solution for the effective implementation of the storage system is presented. Apart from the active power management performed according to the prosumer’s needs, the storage inverter provides the ancillary service of voltage regulation in the network according to the requirements of the network operator. A control strategy involving algorithms for voltage regulation without prejudice to the prosumer’s interest is described in the paper. Reactive power is used first as a control signal and if the required voltage effect cannot be reached, then the active power in the controlled phase is additionally changed and the Energy Storage System (ESS) loading is redistributed in phases in such a way that the total active power set by the prosumer program remains unchanged. The efficiency of the control strategy was tested by means of a simulation model in the PSCAD/EMTDC program. The results of the simulations are presented.

scholarly journals Coordinated Control of Interconnected Microgrid and Energy Storage System

2018 ◽  
Vol 8 (6) ◽  
pp. 4781
Author(s):  
Md. Asaduz-Zaman ◽  
Md. Habibur Rahaman ◽  
Md. Selim Reza ◽  
Md. Mafizul Islam
Keyword(s):  
Energy Storage ◽  
Storage System ◽  
Energy Storage System ◽  
Frequency Regulation ◽  
Spinning Reserve ◽  
Island Area ◽  
Load Demand ◽  
Loading Constraints ◽  
Power Frequency ◽  
The Cost

Several microgrids can be interconnected together to enhance the grid reliability and reduce the cost of supplying power to an island area where conventional power grid cannot be connected. Source and load demand do not properly balance always. Besides that, sometimes power and frequency fluctuation has occurred in MG at island mode. Need to design a special control for maintaining the state of charge (SoC) of energy storage system. This paper proposes a new power supply system for an island area that interconnects two microgrids with a single energy storage system (ESS). An algorithm has been proposed that control the microgrids energy storage system for spinning reserve and load power/frequency regulation purpose. The minimum loading constraints of diesel engine generator (DEG) is considered and the SOC of the ESS is properly maintained.

scholarly journals Efficiency Comparison of DC and AC Coupling Solutions for Large-Scale PV+BESS Power Plants

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4823
Author(s):  
Francesco Lo Franco ◽  
Antonio Morandi ◽  
Pietro Raboni ◽  
Gabriele Grandi
Keyword(s):  
Power Plants ◽  
Large Scale ◽  
Storage System ◽  
Energy Storage System ◽  
Operating Conditions ◽  
Frequency Regulation ◽  
Regulation Services ◽  
Primary Power ◽  
Efficiency Comparison ◽  
Battery Energy

In large-scale photovoltaic (PV) power plants, the integration of a battery energy storage system (BESS) permits a more flexible operation, allowing the plant to support grid stability. In hybrid PV+BESS plants, the storage system can be integrated by using different power conversion system (PCS) layouts and different charge–discharge strategies. In the AC-coupling layout, the BESS is connected to the ac-side of the system through an additional inverter. In the DC-coupling layout, the BESS is connected to the dc-side, with or without a dedicated dc–dc converter, and no additional inverter is needed. Referring to a 288 MWp PV plant with a 275 MWh BESS, this paper compares the PCS efficiency between AC- and DC-coupling solutions. The power injected into the grid is obtained considering providing primary power-frequency regulation services. A charging and discharging strategy of the BESS is proposed to ensure cyclic battery energy shifting. The power flows in the different components of the system that are obtained under realistic operating conditions, and total energy losses and annual average efficiency are calculated accordingly. Finally, results show a higher efficiency of DC-coupling compared to the AC-coupling layout.

scholarly journals Sizing and Sitting of DERs in Active Distribution Networks Incorporating Load Prevailing Uncertainties Using Probabilistic Approaches

2021 ◽  
Vol 11 (9) ◽  
pp. 4156
Author(s):  
Amin Foroughi Nematollahi ◽  
Hossein Shahinzadeh ◽  
Hamed Nafisi ◽  
Behrooz Vahidi ◽  
Yassine Amirat ◽  
...  
Keyword(s):  
Storage System ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Optimal Placement ◽  
Distribution Model ◽  
Optimal Size ◽  
Diesel Generator ◽  
Supply Source ◽  
Bee Colony ◽  
Pv Generation

In this study, a microgrid scheme encompassing photovoltaic panels, an energy storage system, and a diesel generator as a backup supply source is designed, and the optimal placement for installation is suggested. The main purpose of this microgrid is to meet the intrinsic demand without being supplied by the upstream network. Thus, the main objective in the design of the microgrid is to minimize the operational cost of microgrid’s sources subject to satisfy the loads by these sources. Therefore, the considered problem in this study is to determine the optimal size and placement for generation sources simultaneously for a microgrid with the objectives of minimization of cost of generation resources along with mitigation of power losses. In order to deal with uncertainties of PV generation and load forecasting, the lognormal distribution model and Gaussian process quantile regression (GPQR) approaches are employed. In order to solve the optimization problem, the lightning attachment procedure optimization (LAPO) and artificial bee colony (ABC) methods are employed, and the results are compared. The results imply the more effectiveness and priority of the LAPO approach in comparison with ABC in convergence speed and the accuracy of solution-finding.

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