scholarly journals An Innovative Operation Strategy of ESS for Capacity Expansion of Renewable Energy and Customer Load with Electric Vehicle Chargers in Low Voltage Distribution Systems

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4668
Author(s):  
Kyung-Sang Ryu ◽  
Dae-Jin Kim ◽  
Yang-Hyun Nam ◽  
Heesang Ko ◽  
Byungki Kim ◽  
...  

This paper proposes an innovative operation strategy to extend the acceptance of EVC (Electric Vehicle Charger) and RES (Renewable Energy Resource) in LVDS (Low Voltage Distribution System) by introducing an ESS (Energy Storage System). In conventional LVDS, the load and RES capacity are designed not to exceed the pole transformer capacity. However, when the ESS is connected to the end of LVDS and the bidirectional power flow becomes possible, the linkable capacity of the load and renewable energy can be improved up to twice the capacity of the pole transformer. In addition, even though the power consumption of the load and the power generation of RES exceed the pole transformer capacity, it is possible to maintain the feeder capacity and grid voltage within the allowable limit by the appropriate operation of the ESS. The simulations are performed in the environment of PSCAD/EMTDC, and the ability of the proposed strategy is assessed and discussed.

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2909 ◽  
Author(s):  
Aristotelis Tsimtsios ◽  
Dionisis Voglitsis ◽  
Ioannis Perpinias ◽  
Christos Korkas ◽  
Nick Papanikolaou

The upcoming adoption of low-voltage-ride-through requirements in low-voltage distribution systems is expected to raise significant challenges in the operation of grid-tied inverters. Typically, these inverters interconnect photovoltaic units, which are the predominant distributed energy resource in low-voltage distribution networks, under an umbrella of standards and protection schemes. As such, a challenging issue that should be considered in low-voltage distribution network applications, regards the coordination between the line protection scheme (typically consisting of a non-settable fuse) and the low-voltage-ride-through operation of photovoltaic generators. During a fault, the fuse protecting a low-voltage feeder may melt, letting the generator to continue its ride-through operation. Considering that the efficacy/speed of the anti-islanding detection is affected by ride-through requirements, this situation can lead to protracted energization of the isolated feeder after fuse melting (unintentional islanding). To address this issue, this paper proposes a fault-current-limitation based solution, which does not require any modification in the existing protection scheme. The operation principles, design, and implementation of this solution are presented, while, its effectiveness is supported by extensive simulations in a test-case low-voltage distribution system. A discussion on the presented results concludes the paper.


Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2517
Author(s):  
Diogo Rupolo ◽  
Benvindo Pereira Junior ◽  
Javier Contreras ◽  
José Mantovani

In this paper, a multiobjective approach to carry out the planning of medium-voltage (MV) and low-voltage (LV) distribution systems, considering renewable energy sources (RES) and robustness, is proposed. Due to the uncertainties associated with RES and demand, the proposed planning methodology takes into account a robust planning index (RPI). This RPI allows us to evaluate the robustness estimation associated with each planning solution. The objective function in the mathematical model considers the costs of investment and operation and the robustness of the planning proposals. Due to the computational complexity of this problem, which is difficult to solve by means of classical optimization techniques, MV/LV planning is solved by a decomposition search and a general variable neighborhood search (GVNS) algorithm. To demonstrate the efficiency and robustness of this methodology, tests are performed in an integrated distribution system with 50 MV nodes and 410 LV nodes. Our numerical results show that the proposed methodology makes it possible to minimize costs and improve robustness levels in distribution system planning.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5430
Author(s):  
Daisuke Iioka ◽  
Takahiro Fujii ◽  
Toshio Tanaka ◽  
Tsuyoshi Harimoto ◽  
Junpei Motoyama

Reverse power flow from a photovoltaic (PV) system in a distribution system causes a voltage rise. A relative study regarding the reduction in the distribution feeder voltage depending on system conditions and the magnitude of reverse power flow has been conducted. Several methods for mitigating voltage rise have been proposed; however, the influence of these methods on the voltage in the distribution system, where the voltage is reduced due to reverse power flow, remains to be determined. In this study, the effect of constant power factor control in low-voltage PV systems, which are widely used as voltage rise countermeasures in distribution systems, was analyzed under the condition that the distribution line voltage decreases due to reverse power flow. Consequently, the constant power factor control of the low-voltage distribution system was found to adversely reduce voltage in the medium voltage distribution system due to the consumption of lagging reactive power by the PV systems.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4367
Author(s):  
Hyun-Tae Kim ◽  
Jungju Lee ◽  
Myungseok Yoon ◽  
Moon-Jeong Lee ◽  
Namhun Cho ◽  
...  

Recently, the demand for electricity has been increasing worldwide. Thus, more attention has been paid to renewable energy. There are acceptable limits during the integration of renewable energy into distribution systems because there are many effects of integrating renewable energy. Unlike previous studies that have estimated the distributed energy resource (DER) hosting capacity using the standard high voltage and probability approach, in this study, we propose an algorithm to estimate the DER hosting capacity by considering DER outages due to abrupt disturbances or uncertainties based on the generator ramp rate and voltage stability, which involves analysis of the low-voltage aspects. Furthermore, this method does not involve a complicated process or need large amounts of data to estimate the DER hosting capacity because it requires only minimum data for power flow. The proposed algorithm was applied to the IEEE-33 radial distribution system. According to the DER capacity, a voltage stability analysis based on continuation power flow (CPF) was conducted in a case of DER outage to estimate the DER hosting capacity in this case study. Thus, the DER hosting capacity was estimated for the IEEE-33 radial distribution system.


2021 ◽  
Author(s):  
Adnan Arapovic

With emerging concerns over climate change and the need for reduced greenhouse gas emissions, together with the growing awareness of the importance of the natural environment and the depletion of the earth's non-renewable energy resources, the generation of electricity from distributed renewable energy resource such as solar photovoltaic (PV) and wind energy has begun to expand at a rapid pace. Proliferation of convert-based distributed energy resources in distribution systems has introduced new challenges in determining the maximum possible fault currents that a power system must be able to withstand without being compromised. Therefore is is imperative to develop the mathematical and software simulation models that approximate the response of converter-based distributed energy resources during a fault on the transmission or distribution system in order to determine the fault current contributions to the electrical grid that a transmission or distribution utility needs to reflect in their connection impact assessments.


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