• 스마트미디어저널
• /
• 제7권2호
• /
• pp.71-77
• /
• 2018

본 논문에서는 신재생에너지 발전과 연계한 에너지저장시스템(ESS)의 최적 운영을 위한 에너지관리시스템(EMS)의 구성요소 설계 시 고려할 기능, 운영 효과 분석과 전력요금 절감 방안을 제안한다. 이를 위해 태양광 발전 시스템에 리튬이온전지 기반의 배터리 시스템과 에너지관리시스템 연계 및 구축방안을 제시하고, 1년 동안 운영 데이터에 대한 분석한 결과를 기술한다. 또한 시스템 운영 효과를 높이기 위한 방안으로 EMS를 이용하여 최대수요 발생시간대의 피크전력을 경부하 시간대 충전전력으로 대체하여 ESS 전용 요금제에 따른 요금편익과 부하 평준화에 기여하는 효과를 제안한다.

• 전기학회논문지
• /
• 제65권2호
• /
• pp.264-268
• /
• 2016

Recently, various energy efficiency optimization activities are ongoing globally by integrating conventional grids with ICT (Information and Communication Technology). In this sense, various smart grid projects, which power suppliers and consumers exchange useful informations bilaterally in real time, have been being carried out. The electric vehicle diffusion program is one of the projects and it has been spotlighted because it could resolve green gas problem, fuel economy and tightening environmental regulations. In this paper, the economics of V2G system which consists of electric vehicles and the charging infrastructure is evaluated comparing electric vehicles for V2G with common electric vehicles. Additional benefits of V2G are analyzed in the viewpoint of load leveling, frequency regulation and operation reserve. To find this benefit, electricity sales is modeled mathematically considering depth of discharge, maximum capacity reduction, etc. Benefit and cost analysis methods with the modeling are proposed to decide whether the introduction of V2G systems. Additionally, the methods will contribute to derive the future production and the unit cost of electric vehicle and battery and to get the technical and economic analysis.

• 설비공학논문집
• /
• 제22권12호
• /
• pp.845-851
• /
• 2010

This study was experimentally performed to find the effects of refrigerant subcooling in the refrigeration system and to propose how to get the efficient use of energy. A refrigerant-subcooling refrigeration system consisted of a typical single vapor-compression refrigeration cycle, a subcooler, and an ice storage tank. The degree of subcooling at the exit of the condenser can be increased by the heat transfer between the subcooler and the ice storage tank. The cold heat in the ice storage tank was stored by using the refrigeration cycle during night time and then used to absorb the heat from the subcooler during daytime. The cooling capacity and COP of this system were higher than those of the conventional system due to the increase in the degree of subcooling. Typically, the refrigerant-subcooling system showed superior performance to the conventional refrigeration system and would also contribute to load leveling.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
• /
• pp.265-267
• /
• 2009

we proposed a grid connected peak load compensation system with high discharge current characteristics based on lithium polymer battery for development of the next generation power-station. The lithium polymer battery has faster discharge current characteristics than conventional battery, so that can compensate high active power demanded by load in a short time using the low capacity battery bank. Therefore, it is possible to control power leveling of grid by measuring storage energy of battery and active power which is needed from load. The validity of proposed system was verified through the simulation and experiment.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2008년도 추계학술대회 논문집
• /
• pp.379-382
• /
• 2008

This paper gives the support method of DSM program(power load leveling for heating and cooling facilities on building). As the national power peak load increases recently, the peak load reduction is needed. So we studied about remote controlling of power load from heating/cooling facilities on building during peak times. To adopt new DSM program, it is very important to design DSM customer supporting system. So in this paper, we dealt with the result of customer survey, and the DSM potential regarding heating/cooling facilities on building. In conclusion, the peak reduction program of heating/cooling facilities is very important and the incentive of customer should be consist of two incentive types as an installation and power reduction.

• 전기학회논문지
• /
• 제65권7호
• /
• pp.1151-1160
• /
• 2016

In recent years, the energy storage systems such as LiB, NaS, RFB(Redox-Flow Battery), Super- capacitor, pumped hydro storage, flywheel, CAES(Compressed Air Energy Storage) and so on have received great attention as practical solutions for the power supply problems. They can be used for various purpose of peak shaving, load leveling and frequency regulation, according to the characteristics of each ESS(energy storage system). This paper will focus at 1 MWh RFB system, which is being developed through the original technology project of energy material. The output of ESS is mainly characterized by C-rate, which means that the total rated capacity of battery will be delivered in 1 hour. And it is a very important factor in the ESS operation scheduling. There can be several options according to the operation intervals 15, 30 and 60minutes. The operation scheduling is based on the optimization to minimize the daily electricity cost. This paper analyzes the cost-saving effects by the each operating time-interval in case that the RFB ESS is optimally scheduled for peak shaving and load leveling.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.951-956
• /
• 2011

As the evaluation of loading characteristic on tilting mechanism is the most important one of the function test of tilting mechanism, the changing characteristic of load must be investigated on tilting of carbody for both the static and running condition of train. In this study, we reduced the load of tilting mechanism by adjusting the interface of carbody and bogie such as the weight balance, level of underframe, height of leveling valve, height of axle box and center position of tilting actuator with the characteristic curve of load for optimal condition of the tilting mechanism obtained in the previous study. Furthermore, the factor and effect of the interfacial structures respecting the load of tilting mechanism was evaluated by analyzing the changing characteristic of load obtained in the process of adjustment of interfaces. From these data, we will propose the maintenance standards for interfacial structures and tilting mechanism in order to minimize the load of tilting mechanism by analyzing in detail the characteristic of load for the main factors of the interfacial structure effecting on the load of tilting mechanism.

• Journal of Power Electronics
• /
• 제9권6호
• /
• pp.874-883
• /
• 2009

This paper deals with an integrated voltage and frequency (VF) controller for isolated asynchronous generators (IAG) driven by a constant power pico-hydro uncontrolled turbine feeding three-phase four-wire loads. The proposed VF controller is used to control the frequency and voltage of an IAG with load leveling. Such a VF controller is also known as an integrated electronic load controller (IELC) which is realized using an isolated star/polygon transformer with a voltage source converter (VSC) and a battery at its DC bus. The proposed generating system with a VFC is modeled and simulated in MATLAB along with Simulink and Simpower system (SPS) toolboxes. The simulated results are presented to demonstrate the performance of an isolated asynchronous generator feeding three-phase four-wire loads with neutral current compensation.

• 한국정보전자통신기술학회논문지
• /
• 제10권3호
• /
• pp.232-241
• /
• 2017

본 연구는 선행 연구로 진행되었던 과수원 및 농경지에서 사용되는 고소작업차의 안정적인 요소를 설계하기 위하여 진행되었다. Auto leveling system과 수평센서를 이용하여 불규칙하고 경사가진 곳에서 안전하게 작업하기 위하여 유압식 상승리프트를 개발하였으며 고소작업대에서의 제어를 하기 위하여 원격 제어를 포함한 중앙집중식 컨트롤러의 개발을 진행하였다. 개발된 모듈을 통하여 고소작업대에서의 안정적 제어가 되는지 현장 시 운행을 실시하였으며, 고소 작업대의 구조해석을 통하여 작업자가 작업대에서 안전하게 작업을 할 수 있는 최대 적재 하중 및 균등 적재량을 제시함으로서 보다 안전에 대해 유의하도록 하였다. 각 부위별 설계 및 검증, 제작을 통하여 완성된 고소기계차의 현장 시운행을 통하여 프로토타입의 고소기계차를 제작하였고, 몇 가지의 수정 보완 사항을 통하여 연구를 지속적으로 행할 예정이다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2016년도 전력전자학술대회 논문집
• /
• pp.453-454
• /
• 2016

The ESS(Energy Storage System) connected with distributed generation is drawing attention due to improving the quality load leveling, peak shaving for enhancing reliability of the power grid. The grid-connected inverter makes frequency adjustment to the active power's charge discharge according to the load variation. In addition, the inverter is possible to act as a reactive power compensation device to eliminate harmonic operates as power factor change inhibiting, anti-transient voltage fluctuation, active filter. In this paper, we propose a design method of igbt stack considering the reactive power supply capacity to improve the quality and reliability of the inverter. Moreover, the grid-connected inverter considering the four-quadrant rated operation designed stack and verified the feasibility of the design through a thermal analysis.