• 한국산업융합학회 논문집
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• 제25권1호
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• pp.111-119
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• 2022

This paper is about power transfer between heterogeneous systems in zero-energy buildings. Currently, electricity used in buildings, from renewable energy generation power in buildings, consists of alternating current networks. In order to use electricity, alternating current must be converted to direct current, which typically results in a loss of 10%. In order to solve this problem, research is needed to reduce power loss as much as possible by implementing both a DC network and an AC network in a zero-energy building. Therefore, in this paper, an inter-link converter capable of bidirectional power transfer between DC and AC networks applied to zero-energy buildings is developed. The structure of the inter-link converter to be developed was proposed and its feasibility was verified through simulations and experiments.

• 조명전기설비학회논문지
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• 제29권4호
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• pp.85-94
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• 2015

Recently, research on the smart grid that combines ICT(Information & Communication technology) to the power system has been actively progressed. If the occupancy of the EV(Electric vehicle) is increased. the V2G(Vehicle to grid) system is available which constitutes the micro-grid through battery of EV. V2G system performs load leveling and efficient energy consumption by battery operation considering load condition. But, if the battery is used only depending on the electricity rates, it doses not consider the life of the battery. The ACC(Achievable cycle) and the total transferable energy of battery varies corresponding to the selected DOD(Depth of discharge). In this paper, the optimal DOD selection method of V2G system considering battery wear cost and average driving distance of EV. Also, the total revenue prediction of various nation is presented considering the actual electricity costs per hour.

• 전기학회논문지
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• 제61권11호
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• pp.1584-1589
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• 2012

The grid-interconnected microgrid can be able to operate with and without the utility microgrid to supply electricity. when the microgrid operates in grid-connected mode, the frequency of the microgrid synchronizes with the system frequency. In this case, the frequency of the microgrid has small variation which is able to change the output of distributed generation with a droop controller. Thus, the small variation of frequency can make the distributed generation generate unnecessary electricity consistently. In this paper, we propose a frequency droop control with a dead band so as to prevent the distributed generations from generating unnecessary output while in grid-interconnected mode. In addition, a distributed generation can have a restoration control to restore the frequency changed by a droop control as a rated frequency. Also, we state the problem of restoration control with a dead band, and propose its solution when the microgrid operates in stand alone mode. We simulate the proposed droop control using PSCAD/EMTDC to verify the validity of the control.

• 한국태양광발전학회지
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• 제6권1호
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• pp.86-91
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• 2020

Nepal is among the richest in terms of water resource availability and it is one of the most important natural resources of the country. Currently, 72% of the population is electrified through the national grid system. The power generation mix into the grid is hydro dominated with minor shares generated from solar and thermal (accounts for less than 1%). To achieve sustainable development in the power sector it is essential to diversify power generation mix into the grid. Knowing the facts, the government has a plan to achieve a 5-10% share of power generation from solar and mix it into the grid system. Solar is the second most abundant, prominent and free source of renewable in the context of Nepal. This study mainly focuses on the grid-connected solar system, its importance, present status, government efforts, and its need. It is based on the review of literature, news published in national newspaper online news and international organization's report.

• 산업기술연구
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• 제30권A호
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• pp.9-15
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• 2010

Recently, Smart Grid is a emerging topic in power and communication industry. Smart Grid refers to a evolution of the electricity supply infrastructure that monitors, protects, and intelligently optimize the operation of the interconnected elements including various type of generators, power grid, building/home automation system and end-use consumers. In order to successful implementation of Smart Grid, energy management function will be the key factor that coordinates and optimally controls the various loads according to the operating condition and environments, and the load patterns in residential and commercial building will be required as fundamental element for load management. In this study, we collects many types of energy usage data of electric appliances, analyze their load curves, and make the general load patterns for electrical appliance.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1251-1260
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• 2013

This paper presents the optimal scheduling of hourly consumption in a residential community (community, neighborhood, etc.) based on real-time electricity price. The residential community encompasses individual residential loads, communal (shared) loads, and local generation. Community-aggregated loads, which include residential and communal loads, are modeled as fixed, adjustable, shiftable, and storage loads. The objective of the optimal load scheduling problem is to minimize the community-aggregated electricity payment considering the convenience of individual residents and hourly community load characteristics. Limitations are included on the hourly utility load (defined as community-aggregated load minus the local generation) that is imported from the utility grid. Lagrangian relaxation (LR) is applied to decouple the utility constraint and provide tractable subproblems. The decomposed subproblems are formulated as mixed-integer programming (MIP) problems. The proposed model would be used by community master controllers to optimize the utility load schedule and minimize the community-aggregated electricity payment. Illustrative optimal load scheduling examples of a single resident as well as an aggregated community including 200 residents are presented to show the efficiency of the proposed method based on real-time electricity price.

• 전기학회논문지
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• 제65권7호
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• pp.1151-1160
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• 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.

• 한국전자통신학회논문지
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• 제18권1호
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• pp.23-28
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• 2023

자동전력량 측정이 가능한 AMI(: Advanced Metering Infrastructure)의 설치 비율은 전국적으로 43% 미만이고 특히 지역 기준인 경우에는 10.5%로 매우 열악한 상태이다. 따라서 스마트그리드를 위해서는 전력량계의 자동 정보 기록이 필요하므로 이를 위해서 기존 전력계량계를 개선하여 원격검침 및 사용 제어가 가능한 시스템 개발이 필요하다. 본 논문에서는 기존 전력량계를 AMI기능이 가능하게 하려면 IoT 및 AI를 이용하여 스마트 그리드 핵심인 AMI를 위한 기존 전력 계량기의 원격검침 및 제어 기술 개발을 수행하였다. 주요 연구 내용은 SG를 위한 전력계량기 감지 장치로 변환하기 위하여 Tensorflow와 Open-cv를 이용하여 숫자를 인식하였고, SG를 위한 전력계량기 원격검침 기능 테스트를 위해서는 Intel-Edson 하드웨어와 연동하여 장치를 구성하여 성능을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.546-549
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• 2022

자동전력량 측정이 가능한 AMI (advanced metering infrastructure)의 설치 비율은 전국적으로 43% 미만이고 특히 지역 기준인 경우에는 10.5%로 매우 열악한 상태이다. 따라서 스마트그리드를 위해서는 전력량계의 자동 정보 기록이 필요하므로 이를 위해서 기존 전력계량계를 개선하여 원격검침 및 사용 제어가 가능한 시스템 개발이 필요하다. 본 논문에서는 기존 전력량계를 AMI기능이 가능하게 하려면 IoT 및 AI를 이용하여 스마트 그리드 핵심인 AMI를 위한 기존 전력 계량기의 원격검침 및 제어 기술 개발을 수행하였다. 주요 연구 내용은 SG를 위한 전력계량기 감지 장치로 변환하기 위하여 Tensorflow와 Open-cv를 이용하여 숫자를 인식하였고, SG를 위한 전력계량기 원격검침 기능 테스트를 위해서는 Intel-Edson 하드웨어와 연동하여 장치를 구성하여 성능을 확인하였다.

• 디지털융복합연구
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• 제11권4호
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• pp.279-284
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• 2013

지구환경 개선을 위한 저탄소 배출 및 그린에너지에 관심이 높아지고 있으며, 이를 이루기 위한 기존의 전력망에 IT기술을 결합하여 보다 효율적이고 친환경적인 지능형 전력망을 이루는 스마트 그리드 사업이 전 세계적으로 활발히 전개되고 있다. 스마트 그리드는 양방향 디지털 기술을 사용하여 공급 업체와 소비자 사이에 전기를 제공하며, 소비자 집에 있는 지능형 가전이나, 에너지 절약 비용을 절감하고 안정성, 효율성 및 투명성을 높이기 위해 필요하며, 앞으로 지속적으로 발전될 것을 예상한다. 하지만, 스마트 그리드를 구축하기 위해서 반드시 선행되어야 하는 사항인 보안 모델을 구축하여 지능형 전력망을 안전하고 효율적으로 사용되도록 구축하는 방안을 제시하는 연구이다.