• Title, Summary, Keyword: Energy storage system (ESS)

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A Study on the Dynamic Voltage Restorer to Application Luminaire for Emergency Exit Sign Operation to the Energy Storage System (에너지 저장장치(ESS)의 비상 유도등 동작을 적용한 순간전압강하 보상장치에 관한 연구)

  • Hwang, Lark-Hoon;Na, Seung-kwon;Kim, Jin Sun
    • The Journal of Advanced Navigation Technology
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    • v.19 no.5
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    • pp.433-439
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    • 2015
  • Recently, Interest in power the quality was increased because of increasing the use of sensitive load equipment into an electrical disturbance such as computer, Electricity, Electronics, Telecommunications and semiconductor device. In addition, To enhance power quality, the instantaneous voltage drop occurred in precision load equipment is a need for proper compensation. In order to solve the problem, The developed dynamic voltage restorer (DVR) using an electric double layer capacitor (EDLC) has been applied. In this paper, We will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. Also, As a emergency luminaires of emergency power supply that we can support more than 10 years of life was confirmed the applicability of hybrid capacitor.

Normal Operation Characteristics of 30kW Scale CVCF Inverter-Based Micro-grid System (30kW급 CVCF 인버터 기반의 Micro-grid의 정상상태 운용특성에 관한 연구)

  • Ferreira, Marito;Lee, Hu-Dong;Tae, Dong-Hyun;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.662-671
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    • 2020
  • Recently, for the purposes of reducing carbon dioxide(CO2) emissions in the island area, countermeasures to decrease the operation rate of diesel generator(DG) and to increase one of renewable energy sources(RES) is being studied. In particular, the demonstration and installation of stand-alone micro-grid(MG) system which is composed of DG, RES and energy storage system(ESS) has been implemented in some island areas such as Gapa-do, Gasa-do and Ulleung-do island. However, many power quality(PQ) problems may be occurred due to an intermittent output of RES including photovoltaic(PV) system and wind power(WP) system in a normal operating of constant voltage & constant frequency(CVCF) inverter-based MG system. Therefore, this paper presents a modeling of the 30kW scale MG system using PSCAD/EMTDC, and also implements a 30kW scale CVCF inverter-based MG system as test devices to analyze normal operating characteristics of MG system. From the simulation and test results, it is confirmed that the proposed methods are useful and practical tools to improve PQ problems such as under-voltage, over-voltage and unbalanced load in CVCF inverter-based MG system.

Development of 80kW Bi-directional Hybrid-SiC Boost-Buck Converter using Droop Control in DC Nano-grid (DC 나노그리드에서 Droop제어를 적용한 80kW급 양방향 하이브리드-SiC 부스트-벅 컨버터 개발)

  • Kim, Yeon-Woo;Kwon, Min-Ho;Park, Sung-Youl;Kim, Min-Kook;Yang, Dae-Ki;Choi, Se-Wan;Oh, Seong-Jin
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.4
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    • pp.360-368
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    • 2017
  • This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.

Feasibility of Bladder Compression Molded Prepreg as Small Wind Turbine Blade Material (소형 풍력 터빈 블레이드 재료로서 블래더 가압 방식 몰드 성형 프리프레그의 타당성)

  • Yi, Bo-Gun;Seo, Seong-Won;Song, Myung-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.2
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    • pp.95-101
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    • 2020
  • The wind turbine blades should be designed to possess a high stiffness and should be fabricated with a light and high strength material because they serve under extreme combination of lift and drag forces, converting kinetic energy of wind into shaft work. The goal of this study is to understand the basic knowledge required to curtail the process time consumed during the construction of small wind turbine blades using carbon fiber reinforced polymer (CFRP) prepeg composites. The configuration of turbine rotor was determined using the QBlade freeware program. The fluid dynamics module simulated the loads exerted by the wind of a specific speed, and the stress analysis module predicted the distributions of equivalent von Mises stress for representing the blade structures. It was suggested to modify the shape of test specimen from ASTM D638 to decrease the variance in measured tensile strengths. Then, a series of experiments were performed to confirm that the bladder compression molded CFRP prepreg can provide sufficient strength to small wind turbine blades and decrease the cure time simultaneously.

CO2 Methanation Characteristics over Ni Catalyst in a Pressurized Bubbling Fluidized Bed Reactor (가압 기포 유동층 반응기에서의 Ni계 촉매 CO2 메탄화 특성 연구)

  • Son, Seong Hye;Seo, Myung Won;Hwang, Byung Wook;Park, Sung Jin;Kim, Jung Hwan;Lee, Do Yeon;Go, Kang Seok;Jeon, Sang Goo;Yoon, Sung Min;Kim, Yong Ku;Kim, Jae Ho;Ryu, Ho Jeong;Rhee, Young Woo
    • Korean Chemical Engineering Research
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    • v.56 no.6
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    • pp.871-877
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    • 2018
  • Storing the surplus energy from renewable energy resource is one of the challenges related to intermittent and fluctuating nature of renewable energy electricity production. $CO_2$ methanation is well known reaction that as a renewable energy storage system. $CO_2$ methanation requires a catalyst to be active at relatively low temperatures ($250-500^{\circ}C$) and selectivity towards methane. In this study, the catalytic performance test was conducted using a pressurized bubbling fluidized bed reactor (Diameter: 0.025 m and Height: 0.35 m) with $Ni/{\gamma}-Al_2O_3$ (Ni70%, and ${\gamma}-Al_2O_3$30%) catalyst. The range of the reaction conditions were $H_2/CO_2$ mole ratio range of 4.0-6.0, temperature of $300-420^{\circ}C$, pressure of 1-9 bar, and gas velocity ($U_0/U_{mf}$) of 1-5. As the $H_2/CO_2$ mole ratio, temperature and pressure increased, $CO_2$ conversion increases at the experimental temperature range. However, $CO_2$ conversion decreases with increasing gas velocity due to poor mixing characteristics in the fluidized bed. The maximum $CO_2$ conversion of 99.6% was obtained with the operating condition as follows; $H_2/CO_2$ ratio of 5, temperature of $400^{\circ}C$, pressure of 9 bar, and $U_0/U_{mf}$ of 1.4-3.