• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.127-128
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• 2015

에너지 저장 시스템(ESS, Energy Storage System)은 태양광(PV), 풍력(WT) 등과 같은 신재생 에너지 출력안정화, 계통 전력품질 개선, 수용가 에너지효율화 등의 분야에 이용되고 있다. 에너지 저장 시스템은 전력변환장치와 에너지 저장 장치로 구성되며, 에너지 저장 장치로 배터리를 많이 사용하고 있다. 전력변환장치 및 제어기의 설계 및 검증을 위해서는 배터리를 전력변환장치에 연계하여야 한다. 하지만 배터리의 경우 고가에 관리가 어렵기 때문에 일반적으로 DC전원 모의 장치를 이용한다. 본 논문에서는 에너지 저장 시스템용 전력 변환장치 및 제어기의 설계 및 현실적인 검증이 가능하도록 배터리 특성을 고려한 DC전원 모의장치를 개발하였다.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.97-98
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• 2015

에너지 저장 시스템(ESS, Energy Storage System)은 태양광(PV)발전, 풍력(WT)발전시스템 등과 같은 신재생 에너지 출력안정화, 계통 전력품질 개선, 수용가 에너지효율화 등의 분야에 이용되고 있다. 에너지 저장 시스템은 전력변환장치와 에너지 저장 장치로 구성되며, 에너지 저장 장치로 배터리를 많이 사용하고 있다. 전력변환장치 및 제어기의 설계 및 검증을 위해서는 배터리를 전력변환장치에 연계하여야 하지만 배터리의 경우 고가에 관리가 어려운 문제로 인해 일반적으로 배터리 모의 장치를 이용한다. 본 논문에서는 대용량 에너지 저장 시스템용 전력변환장치 및 제어기의 설계와 현실적인 검증이 가능한 MW급 PCS 성능검증용 배터리 모의장치를 개발하였다.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.786-794
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• 2015

In this paper, a new power control strategy for the bipolar-type low voltage direct current (LVDC) distribution system is being proposed. The dc distribution system is considered as an innovative system according to the increase of dc loads and dc output type distribution energy resources (DERs) such as photovoltaic (PV) systems and energy storage systems (ESS). Since the dc distribution system has many advantages such as feasible connection of DERs, reduction of conversion losses between dc output sources and loads, no reactive power issues, it is very suitable solution for new type buildings and residences interfaced with DERs and ESSs. In the bipolar-type, if it has each grid-interfaced converter, both sides (upper, lower-side) can be operated individually or collectively. A complementary power control strategy using two ESSs in both sides for effective and reliable operation is proposed in this paper. Detailed power control methods of the host controller and local controllers are described. To verify the performances of the proposed control strategy, simulation analysis using PSCAD/EMTDC is being performed where the results show that the proposed strategy provides efficient operations and can be applied to the bipolar-type dc distribution system.

• Journal of IKEEE
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• v.23 no.4
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• pp.1280-1287
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• 2019

Grid-connected bidirectional PCS(Power Conditioning System) technology is a technology for implementing distributed renewable energy smart grid. And it is always charged by using power collected from solar modules and commercial grid power among vast smart grid systems, and stored when needed.It is a hybrid energy storage device that allows power to be released into the low voltage system. To this end, a PV input power converter with MPPT function, a bidirectional power converter for battery charging and discharging, and a DC Link input are output to a 3 phase 380V AC system, and if nessary, the bidirectional DC/DC converter We designed and developed a PCS with three power converter structures composed of inverters that perform battery charging. Currently, this system is applied to the site of Jeju, which is vulnerable to power outages and fire accidents.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• v.5 no.5
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• pp.623-630
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• 2018

The renewable energy systems have been in the spotlight as an alternative for environmental issues. Therefore, the governmental policies are being implemented to spread of promote power generation system using renewable energy in various countries around the world. In addition, Korea has also developed a policy called the power trading contract which can profit from electricity produced from renewable power generation system through Korea Electric Power Corporation (KEPCO) and Korea Power Exchange (KPX). As a result, the power trading contracts can trade power after self-consuming in-house by using small-scale renewable power system for residential customers as well as electricity retailers. The power trading contracts applicable as a small-scale power system have a 'Net metering (NM)' and a 'Power Purchase Agreement (PPA)', and these two types of power trading contracts trade surplus power, but payment method of each power trading is different. The microgrid proposed in this paper is based on grid connected microgrid using Photovoltaic (PV) system and Energy Storage System (ESS), that supplied power to residential demand, we evaluate the operation cost of microgrid by power demand in each power trading contracts and propose the appropriate power trading contracts according to electricity demand.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.393-398
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• 2015

City or Community-scale Energy Management System(CEMS) is used to reduce the total energy consumed in the city by arranging the energy resources efficiently at the planning stage and controlling them economically at the operating stage. Of the operational functions of the CEMS, generation forecasting of renewable energy resources is an essential feature for the effective supply scheduling. This is because it can develop daily operating schedules of controllable generators in the city (e.g. diesel turbine, micro-gas turbine, ESS, CHP and so on) in order to minimize the inflow of the external power supply system, considering the amount of power generated by the uncontrollable renewable energy resources. This paper is written to introduce numerical models for photo-voltaic power generation prediction based on the weather forecasting information. Unlike the conventional methods using the average radiation or average utilization rate, the proposed models are developed for CEMS applications using the realtime weather forecast information provided by the National Weather Service.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.61-68
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• 2021

The application of renewable energies such as wind and solar has become an inevitable choice for many countries in order to achieve the reduction of greenhouse gases and healthy economic development. However, due to the intermittent characteristics of renewable energy, the issue with integrating a larger proportion of renewable energy into the grid becomes more prominent. A complex energy system, usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply. Compared with the power system, control and optimization of the complex energy system become more difficult in terms of modeling, operation, and planning. The main purpose of the complex energy system retrofit for samado island with microgrid system is to coordinate the operation with various distributed energy resources, energy storage systems, and power grids to ensure its reliability, while reducing the operating costs and achieving the optimal economic benefits. This paper suggests the improved complex energy system of samado island with optimal microgrid system. The results of test operation show about 12% lower SOC variation band of ESS, elimination of operation limit in PV and reduction of operation time in diesel generator.

• 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.

• Journal of Environmental Impact Assessment
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• v.26 no.4
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• pp.217-226
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• 2017

Although the effects of climate change are universal, Small Island Developing States (SIDS) are considered to be most vulnerable. SIDS heavily rely on imported oil and fossil fuels for electricity generation and transportation, which makes them economically vulnerable and exposed to fluctuating oil price. Among the reasons SIDS highly depend on diesel fuel is due to the dispersed population living in remote islands which means, providing electricity through on on-grid system is difficult. Fiji as one of the SIDS, has actively promoted renewable sourced energy through a national plan to mitigate the impacts of climate change. In order to determine how feasible implementing a renewable energy (RE) system will be in Fiji, this study chose a remote island called Mavuva Island to test application of a hybrid RE system using HOMER. A combination of energy storage system (ESS), solar photovoltaic (PV) and diesel generator turns out to be the most cost effective and optimal configuration, resulting in effective greenhouse gas reduction for the given region.