• Title, Summary, Keyword: Standalone

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A Field State Investigation on Standalone PV streetlight for Development of Real-time Analysis Technology (독립형 태양광 가로등의 실시간 분석기술 개발을 위한 실태조사)

  • Kim, Doo Hyun;Kim, Sung Chul;Hwang, Dong Kyu
    • Journal of the Korean Society of Safety
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    • v.28 no.5
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    • pp.10-14
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    • 2013
  • This paper is aimed to investigate the actual conditions of standalone PV(Photovoltaics) streetlight in public place and analyze cause of failure and derive the method of decrease for standalone PV streetlight. The cost of installing standalone PV streetlight in a public for the safety and convenience of life is expensive(300 million won per unit). Management of standalone PV streetlight is important because it is operating system itself, after installation, but concern degree of management is very low and development of technology has not been done. Accordingly, standalone PV streetlight in public place is not operate in night, this phenomenon is lasted for several days to months. Therefore this study, for standalone PV streetlight constantly to keep the normal operation, investigation conducted to check status of standalone PV streetlight(50 units), the voltage of the main parts and analyze the cause of the failure. In addition, the improvement of standalone PV streetlight is suggested by using FTA(fault tree analysis).

Control and Operating Modes of Battery Energy Storage System for a Stand-Alone Microgrid with Diesel Generator (디젤발전기가 포함된 독립형 마이크로그리드에서의 BESS 제어기법 및 운전모드 연구)

  • Jo, Jongmin;An, Hyunsung;Kim, Jichan;Cha, Hanju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.2
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    • pp.86-93
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    • 2018
  • In this work, control methods and operating modes are proposed to manage standalone microgrid. A standalone microgrid generally consists of two sources, namely, battery energy storage system (BESS) and diesel generator (DG). BESS is the main source that supplies active and reactive power regardless of load conditions, whereas DG functions as an auxiliary power source. BESS operates in a constant voltage constant frequency (CVCF) control, which includes proportional-integral + resonant controller in a parallel structure. In CVCF control, the concept of fundamental positive and negative transformation is utilized to generate a three-phase sinusoidal voltage under imbalanced load condition. Operation modes of a standalone microgrid are divided into three modes, namely, normal, charge, and manual modes. To verify the standalone microgrid along with the proposed control methods, a demonstration site is constructed, which contains 115 kWh lead-acid battery bank, 50 kVA three-phase DC - AC inverter, and 50 kVA DG and controllable loads. In the CVCF control, the total harmonic distortion of output voltage is improved to 1.1% under imbalanced load. This work verifies that the standalone microgrid provides high-quality voltage, and three operation modes are performed from the experimental results.

Experimental Study of Standalone Cooling and Heating System using Thermoelectric Element for Vehicles (열전소자를 이용한 차량용 독립 냉난방시스템에 대한 실험적 연구)

  • Lee, Dae-Woong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.8
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    • pp.375-380
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    • 2014
  • The purpose of this paper is to investigate the cooling and heating performance of a standalone-type thermoelectric system equipped with a thermoelectric module. The system consists of a blower and two thermoelectric modules with a fin, which is soldered onto both sides of the thermoelectric module and a courtesy light. The thermoelectric system experiment is conducted with the intake voltage to find the optimum cooling and heating performance of each. The results showed that the cooling capacity and coefficient of performance (COP) were 22 W and 0.31, and the heating capacity and COP were 147 W and 1.1, respectively. In the vehicle cooling and heating performance test in a climate wind tunnel, the results showed that the standalone thermoelectric system's cooling performance was slightly better than the base system; and the heating performance of the standalone thermoelectric system was $54.1^{\circ}C$ and the COP was 1.3, compared to the base system.

Dynamic Analysis and Controller Design for Standalone Operation of Photovoltaic Power Conditioners with Energy Storage

  • Park, Sun-Jae;Shin, Jong-Hyun;Park, Joung-Hu;Jeon, Hee-Jong
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.2004-2012
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    • 2014
  • Energy storage devices are necessary to obtain stable utilization of renewable energy sources. When black-out occurs, distributed renewable power sources with energy storage devices can operate under standalone mode as uninterruptable power supply. This paper proposes a dynamic response analysis with small-signal modeling for the standalone operation of a photovoltaic power generation system that includes a bidirectional charger/discharger with a battery. Furthermore, it proposes a DC-link voltage controller design of the entire power conditioning system, using the storage current under standalone operation. The purpose of this controller is to guarantee the stable operation of the renewable source and the storage subsystem, with the power conversion of a very efficient bypass-type PCS. This paper presents the operating principle and design guidelines of the proposed scheme, along with performance analysis and simulation. Finally, a hardware prototype of 1-kW power conditioning system with an energy storage device is implemented, for experimental verification of the proposed converter system.

Single Sensor Charging System with MPPT Capability for Standalone Streetlight Applications

  • Osman, Siti Rahimah;Rahim, Nasrudin Abd.;Selvaraj, Jeyraj;Al-Turki, Yusuf A.
    • Journal of Power Electronics
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    • v.15 no.4
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    • pp.929-938
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    • 2015
  • Maximum power point tracking (MPPT) and battery charging control are two important functions for a solar battery charger. The former improves utilization of the available solar energy, while the latter ensures a prolonged battery life. Nevertheless, complete implementation of both functions can be complex and costly, especially for low voltage application such as standalone street lamps. In this paper, the operation of a solar battery charger for standalone street light systems is investigated. Using only one voltage sensor, the solar charger is able to operate in both MPPT and constant voltage (CV) charging mode, hence providing high performance at a low cost. Using a lab prototype and a solar simulator, the operation of the charger system is demonstrated and its performance under varying irradiance is validated.

A Study on the Optimal System Sizing of the Standalone Photovoltaic Power Generation System for Uninterruptible Power Supply (독립형 태양광 발전 시스템의 무정전 전력공급을 위한 시스템 용량 최적 선정에 관한 연구)

  • Kim, Ki-Young;Choi, Woojin
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.2
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    • pp.77-85
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    • 2018
  • Renewable energy has been increasingly used and widely acclaimed as one of the solutions to rampant environmental problems. Among numerous kinds of renewable sources, the penetration rate of the PV system is relatively higher than that of others due to ease of installation. However, one disadvantage of the PV system is its dependence on weather condition. The PV system is especially critical when it is used for standalone systems because it cannot operate when the power generated from a PV module is not enough. Therefore, PV systems are often used with an energy storage system, such as batteries, to store backup energy when the weather condition is insufficient to supply power to the system. Blackout time can be reduced by increasing the size of the energy storage system, but it is a trade-off with system cost. In this work, optimal sizing of a standalone PV system is proposed to supply power to the system without blackout. The sizing of PV modules and batteries is performed by a simulation based on actual irradiation data collected during the past five years. The Life cycle costing of each system is evaluated to determine an optimal set of PV modules and batteries among several different combinations. The standalone PV system designed by the proposed method can supply power to the system with no interruption as long as the weather condition is similar to those of the past five years.

Accuracy Analysis of Kinematic SBAS Surveying (SBAS 이동측위 정확도 분석)

  • Kim, Hye In;Son, Eun Seong;Lee, Ho Seok;Kim, Hyun Ho;Park, Kwan Dong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.5
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    • pp.493-504
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    • 2008
  • Space-Based Augmentation System (SBAS), which is one of the GPS augmentation systems, is a Wide-Area Differential GPS that provides differential GPS corrections and integrity data. In this study, we did performance analysis of kinematic SBAS surveying by conducting Real-Time Kinematic (RTK), DGPS, standalone, and SBAS surveys. Considering static survey results as truth, 2-D Root Mean Square (RMS) error and 3-D RMS error were computed to evaluate the positioning accuracy of each survey method. As a result, the 3-D positioning error of RTK was 13.1cm, DGPS 126.0cm, standalone (L1/L2) 135.7cm, standalone (C/A) 428.9cm, and SBAS 109.2cm. The results showed that the positioning accuracy of SBAS was comparable to that of DGPS.

A Study on the Fault Tolerance and High Efficiency Control of 4 Leg DC/DC Converter for Battery Energy Storage System in Standalone DC Micro-grid (독립형 DC마이크로그리드 내 BESS용 4 LEG DC/DC 컨버터의 고장허용 및 고효율 제어에 관한 연구)

  • Choi, Jung-Sik;Oh, Seung-Yeol;Cha, Dae-Seak;Chung, Dong-Hwa
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.9
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    • pp.1239-1248
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    • 2018
  • This paper proposes a fault tolerant and high efficiency operation algorithm for a 4 LEG DC/DC converter for a battery energy storage system(BESS) forming a main power source in a standalone DC micro grid. The BESS for the main power supply in the stand-alone DC micro-grid is required to operate at high speed according to fault tolerant control and load by operating at all times. Fault-tolerance control changes the short-circuit fault to an open-circuit fault by using a fuse in case of leg fault in 4 legs, and operates stably through phase shift control. In addition, considering the loss of the power semiconductor, the number of LEG operation is adjusted to operate at high efficiency in the full load region. In this paper, fault tolerant control and high efficiency operation algorithm of DC/DC converter for BESS in standalone DC micro grid is presented and it is proved through simulation and experiment.

A Development of on Auto Inspection System for Automotive Valve-Seal using Standalone Vision (독립형 비전을 이용한 자동차용 Valve-Seal의 자동 검사시스템 개발)

  • Lee, Kyu-Hun;Kim, Yong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.8
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    • pp.71-80
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    • 2007
  • In this study, an inspection system for valve seal of automotive parts using standalone vision has been developed and presented. The system is comprised of eight CCD cameras, and mechanism that loads the automotive parts to the system for the inspection. An image processing algorithm for detecting two different types of defects of valve seals are developed and the effectiveness of the algorithm is experimentally verified. Inspection process is completed in 0.7 second with acceptable accuracy condition. It is envisaged that this inspection system will have a wide application in the automotive part manufacturing industry in the future.

Development of a Web-based QFD Software (웹기반 품질기능전개(QFD)용 소프트웨어 개발)

  • Lee, Jung-Hwan;Lee, Seung-Hoon;Yoon, Seuk-Dong
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.29 no.1
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    • pp.125-134
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    • 2006
  • QFD(Quality Function Deployment) is a system for translating specific customer needs into detailed product requirements which are deployed throughout design, production, marketing and support operations. QFD is a team tool. However, most of commercial QFD softwares are standalone and therefore offer limited support for teamwork. In this paper, we developed a web-based QFD software to overcome many of the limitations that standalone systems suffer from. That is, this software was developed for synchronizing collaboration between team members distributed not only geographically but also over time. This software was developed by using Visual studio.NET and Microsoft COM+(CBD) technique and can be implemented on the web browser.