• Title/Summary/Keyword: stand-alone operation

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Seamless Transfer Operation Between Grid-connected and Stand-Alone Mode in the Three-phase Inverter (3상 인버터의 계통연계 및 독립운전모드 전환 연구)

  • Lee, Wujong;Jo, Hyunsik;Lee, Hak Ju;Cha, Hanju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.2
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    • pp.201-207
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    • 2013
  • This paper propose seamless transfer operation between grid-connected and stand-alone mode in the three-phase inverter for microgrid. The inverter operates grid-connected mode and stand-alone mode. Grid-connected mode is the inverter connected to grid and stand-alone mode is to deliver energy to the load from inverter at grid fault. When conversion from gird-connected to stand-alone mode, the inverter changes current control to voltage control. When grid restored, the inverter system is conversion from stand-alone to grid-connected mode. In this case, load phase and grid phase are different. Therefore, synchronization is essential. Thus Seamless transfer operation stand-alone to grid-connected mode. In this paper, propose sealmless transfer operation between grid-connceted and stand-alome mode, and this method is verified through simulation and experiment.

Real-time Operation Analysis for Stand-alone Microgrid using RTDS (RTDS를 이용한 독립형 마이크로그리드의 실시간 동작 분석)

  • Lee, Yoon-Seok;Han, Byung-Moon;Won, Dong-Jun;Lee, Hak Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.10
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    • pp.1393-1401
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    • 2014
  • In this paper the operational characteristics of stand-alone microgrid was analyzed using RTDS simulation models. The accuracy of developed simulation models were verified by comparing with the analysis results using the PSCAD/EMTDC simulation models. The proper scenarios and operation algorithms were developed and analyzed in accordance with various situations that can occur in the actual system, so as to establish operation scheme for the stand-alone microgrid system. The developed simulation models can be effectively utilized to design a newly installed stand-alone microgrid and to develop various operation scenarios for stand-alone microgrid. And these models can be applied for analyzing the transient phenomena due to system fault so that system protection can be properly designed.

Design and implementation of IoT based controllers and communication module interfaces for stand-alone solar system

  • Lee, Yon-Sik;Mun, Young-Chae
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.1
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    • pp.129-135
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    • 2019
  • This paper is part of research and development for stand-alone solar system without commercial power supply. It implements firmware of controller for operation of stand-alone solar system by applying IoT technology and also develops communication modules that allow multiple solar lamps to send and receive data through wireless network. The controller of the developed stand-alone solar system can effectively charge the power generated by the solar module, taking into account the battery's charge and discharge characteristics. It also has the advantage of attaching wireless communication modules to solar lamp posts to establish wireless communication networks without incurring communication costs. In addition, by establishing IoT gateway middleware platform for each installation site, it forms a foundation to operate multiple solar lamp posts into multiple clusters. And, it is expected that the data collected in each cluster will be used to enable configuration and control of operational information, thereby inducing convenience and efficiency of remote operation and management.

Functional Properties of Stand-alone Microgrid EMS Application (에너지 자립섬 EMS 어플리케이션의 기능적 특성)

  • Lee, Ha-Lim;Chun, Yeong-Han;Chae, Wookyu;Park, Jungsung
    • KEPCO Journal on Electric Power and Energy
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    • v.2 no.1
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    • pp.115-119
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    • 2016
  • For many past years, research in the operation of stand-alone Microgrid, which provides electric power generated from renewable energy sources and energy storage system instead of diesel generators, has been a major issue in order to prepare the exhaustion of fossil fuel and to protect environment, in island grids. Samso Island, known as the world's first stand-alone Microgrid in Denmark, is connected to the mainland grid through AC system, which has different technical conditions with Korea's isolated power system. Korea's first stand-alone Microgrid has been built in Ga-sa island, Chun-la-nam-do, based on Energy Management System (EMS) operation, and other islands are under construction to follow the next step. These stand-alone Microgrid's has large capacity of Battery Energy Storage System (BESS) and the proportion of the renewable energy sources are large, which makes it necessary to use a Microgrid-Energy Management System (MG-EMS) to operate the grid effectively and economically. However, since the main subject of MG-EMS is different from EMS, specific characteristics and functions must be different as well. In this paper, the necessary characteristics and functions are explained for a general MG-EMS compared to a large power system EMS.

Coordinated Droop Control for Stand-alone DC Micro-grid

  • Kim, Hyun-Jun;Lee, Yoon-Seok;Kim, Jae-Hyuk;Han, Byung-Moon
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.1072-1079
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    • 2014
  • This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

Dynamic Model of Microturbine Generation System for Stand-Alone Mode Operation (마이크로터빈발전시스템 독립운전을 위한 동적 모델링)

  • Cho, Jea-Hoon;Hong, Won-Pyo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.12
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    • pp.210-216
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    • 2009
  • Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market. In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for stand-alone operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in stand-alone operation mode of a DG system.

Characteristics on Stand-alone Operation of a Doubly-fed Induction Generator Applied to Adjustable Speed Gas Engine Cogeneration System

  • Daido, Tetsuji;Miura, Yushi;Ise, Toshifumi;Sato, Yuki
    • Journal of Power Electronics
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    • v.13 no.5
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    • pp.841-853
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    • 2013
  • An application of doubly-fed induction generator (DFIG), which is one of adjustable speed generators, to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supply is one of important roles for the gas engine cogeneration system. However, the DFIG requires initial excitation for startup during a blackout because the DFIG has no excitation source. In this paper, we propose the "blackout start" as a new excitation method to generate a rated voltage at the primary side during a blackout. In addition, a stand-alone operation following a blackout has been investigated by using experimental setup with a real gas engine. Power flows in the generating set with the DFIG at the stand-alone operation have been investigated experimentally. Experimental investigation of the power flow suggests that the generating set with DFIG has optimal speed in minimizing whole system losses.

Design of Grid Connected Photovoltaic System with Stand-alone Operation (독립운전기능을 갖는 계통연계형 태양광 발전시스템의 설계)

  • Kim M.S.;Lee S.H.;Hong J.S.;Choi J.H.
    • Proceedings of the KIPE Conference
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    • 2003.07b
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    • pp.969-972
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    • 2003
  • This paper deal with a necessary factors for design grid connected photovoltaic system with stand-alone operation, and show simulation results of individual functions and multi- operation according to utility condition. Generally, photovoltaic system have only one operation of either stand-alone or line interactive, and have a isolation transformer for electrical isolation from utility therefore it is bulky, weighty, and a high price system as compared with usefulness. In this paper, A topology and algorithm adequate for lightweight, high efficiency, low price, multi function is selected and inquired into the validity using simulation of variable conditions.

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Simulation Analysis and Development of Matlab/Simulink Model for Stand-alone Operation of Emergency Diesel Synchronous Generator-based Hybrid Energy System (비상용 디젤동기발전시스템기반 독립운전 하이브리드에너지시스템 모델 설정 및 시뮬레이션 분석에 관한 연구)

  • Hong, Won-Pyo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.1
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    • pp.70-79
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    • 2015
  • In this paper, enhanced stand-alone operation and development of Matlab/Simulink model of emergency diesel based hybrid energy system is presented. Simulations based on the remote community or islands were performed for PV-diesel-battery hybrid system. Modeling of PV-diesel-battery integrated system is done to perform under the solar radiation and load conditions on Matlab/Simulink platform. The models of diesel generator unit, battery energy storage system, PV and frequency-power control are developed and simulation studies have been carried out under various conditions using Matlab/Simulink and SimPowerSystem. It is demonstrated that the proposed system can provide reliable and good quality power to the customers in diesel synchronous generator-based hybrid energy systems.

Control Method of Distributed-Module Type Photovoltaic Power Conditioners under Stand-alone Operation (분산모듈형 태양광 전력조절기의 독립운전 제어)

  • Seo, Jung-Won;Park, Joung-Hu;Kim, Hye-Rim
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.5
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    • pp.448-457
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    • 2013
  • This paper proposes a control method under stand-alone operating mode for distributed-module type photovoltaic power conditioners. In conventional schemes, there are some problems of a controller saturation in the DC-link (or load) voltage controller when overly-heavy load, light load, and the generated PV power reduction occurs, as well as when a transition occurs from an overly-loaded to normal conditions. To overcome these problems, the proposed controller method switches the main control target from DC-link voltage to the maximum power point, which is closer to the stable operating point when it returns to normal operating conditions. For the analysis, a state-plane trajectory was given and the circuit analysis by PSIM simulation was done. For the verification, a prototype hardware with 110[W] and 50[W] dual photovoltaic modules has been implemented. From the results, it can be seen that PV power tracking is successfully done with the proposed method even under a stand-alone operation mode.