Mobile QR Code QR CODE : The Transactions of the Korean Institute of Electrical Engineers

분산전원의 최적 연계 위치 탐색을 위한 배전선로의 감도 해석 연구 A Study on Sensitivity Analysis of Distribution Line for Optimal Placement Search of DERs

https://doi.org/10.5370/KIEE.2021.70.10.1425

권동영(Dong-Yeong Gwon) ; 최윤혁(Yun-Hyuk Choi)

With the recent increase in the number of DERs, there is a high possibility that voltage quality problems will occur. In order to solve this problem, it is important to determine the optimal location of DERs. Therefore, in this paper, in order to develop an optimization algorithm to determine the optimal placement of DERs, the first step is to perform a sensitivity analysis on the distribution line. At this time, static voltage stability, voltage-active power characteristics and voltage violation rate of distribution lines are reviewed using the actual system data and the OpenDSS module based on Matlab.

에너지효율향상 의무화제도 구성요소 검토 및 정책제언 Implication for Energy Efficiency Resource Standards: Based on Analysis of Policy Framework

https://doi.org/10.5370/KIEE.2021.70.10.1432

김주한(Ju-Han Kim) ; 김유리(Yoo-Ri Kim) ; 강희재(Hee-Jae Kang) ; 김진수(Jin-Soo Kim) ; 이정배(Jung-Bae Lee)

Energy Efficiency Resource Standards(EERS) has been implemented in various countries such as the United States and Italy, and pilot projects are being implemented in Korea. Nevertheless, the legal basis of Korean EERS is vulnerable and there is insufficient discussion about the factors that make up the EERS policy. In consideration of the environment in Korea, the government should adopt an optimal method depending on the extent to which factors are applied. In addition, a reasonable target level and a cost recovery program should be established through agreement with the responsible entities to develop sustainable policy framework.

셀프에너지 밸런싱을 고려한 리튬이온전지용 BMS의 운용알고리즘에 관한 연구 Operation Algorithm of Battery Management System for Li-ion Battery Considering Self-energy Balancing Phenomenon

https://doi.org/10.5370/KIEE.2021.70.10.1443

정민철(Min-Chul Jung) ; 김지명(Ji-Myung Kim) ; 태동현(Dong-Hyun Tae) ; 노대석(Dae-Seok Rho)

Recently, according to the green growth and carbon-neutral policy of government, installation of ESS(energy storage system) with various functions such as peak shaving, frequency regulation and output stabilization of renewable energy sources is rapidly increasing. However, massive scale property has been damaged due to frequent fire accidents in ESS, which is installed and operated on site, and it is reported that most of the fire accidents are occurred during the rest time after full charging. In particular, since Li-ion batteries for ESS are composed of a combination of numerous cells in series and parallel, self-energy balancing phenomenon can be occurred, which current flows from a cell with a high SOC to a cell with a low SOC when the SOC states of cells connected in parallel are different due to deterioration, and the phenomenon is estimated to be one of the causes of the fire accidents. Therefore, this paper proposes a novel circuit configuration and operation algorithm of BMS to prevent self-energy balancing phenomenon in ESS. And also, this paper presents a modeling of self-energy balancing in Li-ion battery using PSCAD/EMTDC and implements a BMS composed of a battery unit, a charger unit, and a self-energy balancing unit, etc., using Labview S/W based on the proposed modeling. From the simulation and test results based on the proposed modeling and test device, it is found that aged cells may be adversely affected by the self-energy balancing phenomenon, and it is confirmed that the proposed BMS is useful tool to prevent self-energy balancing current for the safety of Li-ion battery

라인 기동식 동기형 릴럭턴스 전동기의 설계 파라미터에 따른 동기속도 운전특성에 관한 연구 Study on the Synchronous Speed Operation Characteristics of Line-Start Synchronous Reluctance Motor According to the Design Parameters

https://doi.org/10.5370/KIEE.2021.70.10.1452

김현우(Hyunwoo Kim) ; 강준호(Junho Kang) ; 김정원(Jeongwon Kim) ; 이주(Ju Lee)

In this paper, the operating points of a line-start synchronous reluctance motor (LS-SynRM) are analyzed based on the mathematical model, and the performances such as efficiency and power factor are analyzed using a finite element analysis (FEA). Based on the mathematic model of LS-SynRM, the operating points is analyzed according to the dq-axis inductance. The design parameters that determine the dq-axis inductance and phase resistance are selected as a turn per slot, a stack length, and that determine a barrier design. Using a finite element analysis (FEA), the operating points are analyzed according to the design parameters. Furthermore, the performances of LS-SynRM according to the operating points are analyzed to consider the efficiency and power factor. The performance maps according to three design parameters are analyzed to optimize the efficiency and power factor. To verify FEA result, final LS-SynRM is manufactured and the experiment is performed.

선박용 전자 유량계의 측정 정확도 향상을 위한 여자 코일 시스템의 영향에 관한 연구 A Study on the Effect of Excitation Coil System To Improve Measurement Accuracy of Electromagnetic Flowmeter on the Ship

https://doi.org/10.5370/KIEE.2021.70.10.1460

임상현(Sang Hyeon Im) ; 김경윤(Kyung Youn Kim) ; 박관수(Gwan Soo Park)

An electromagnetic flowmeter calculates the velocity of the fluid and volumetric flow rate by measuring the induced voltage generated by the internal magnetic field. However, because the velocity of the fluid changes according to various external conditions, the uniformity of the magnetic flux density in the measurement section is critical for the accurate measurement of the flow rate. In this study, an improved coil system was proposed to analyze the influence of the internal structure of the electromagnetic flowmeter and to increase the measurement accuracy. The proposed design was verified by analyzing the magnetic flux density distribution via 3D electromagnetic finite element analysis and via experiments using a manufactured prototype.

리튬이온 배터리 노화상태 추정을 위한 건전성 지표 추출 및 CNN 적용 State-of-Health Estimation of Lithium-Ion Battery based on Convolutional Neural Network considering Health Indicator Extraction

https://doi.org/10.5370/KIEE.2021.70.10.1467

문태석(Tae-Suk Mun) ; 한동호(Dong-Ho Han) ; 권상욱(Sang-Uk Kwon) ; 백종복(Jong-Bok Baek) ; 김종훈(Jong-Hoon Kim)

Due to the output characteristics of lithium-ion batteries used in electric vehicles (EVs) vary according to battery aging, accurate prediction of the state-of-health (SOH) reflecting the aging state is important. However, it is difficult to consider factors affecting battery characteristics, such as frequent charging and discharging, operating temperature, and state of charge, so there is a limitation in predicting battery SOH. Even in a model that considers the aging state of the battery under these various conditions, there is also a problem in that the complexity of the calculation process and parameters becomes serious. Therefore, in this paper, in order to research on the estimation of the aging state during operation of the INR18650-25R battery, a health indicator (HI) that can reflect the internal state of the battery according to aging is extracted. This research produce a learning image through the extracted HI and build a model study that enables algorithm learning through the image. The experimental profile used for model training and validation was an Urban Dynamometer Driving Schedule (UDDS), and a Convolutional Neural Network (CNN) with strength in image learning was applied for the estimation algorithm.

머신러닝 이용한 슈퍼접합 모스펫의 최적화 연구 The Study on Machine Learning Approach for Optimization of Superjunction MOSFET

https://doi.org/10.5370/KIEE.2021.70.10.1475

이경엽(Gyeongyeop Lee) ; 하종현(Jonghyun Ha) ; 김정식(Jungsik Kim)

In this work, the the adoption of machine learning for optimization of superjunction MOSFET is investigated. Abundant data (on-resistance(), breakdown voltage(BV)) with various process parameters is earned by technology computer-aided design (TCAD) simulation. We also compare the prediction accuracy between eXtreme Gradient Boosting (XGBoost) and Light Gradient Boosting Machine (LightGBM). XGBoost shows higher accuracy than LightGBM. The use of machine learning is very effective way to reduce the cost and time of superjunction MOSFET development.

비등온 TGA을 이용한 절연재료의 활성화에너지 신뢰도 향상 Improving the Activation Energy Reliability of Insulating Materials Using Non-Isothermal Thermogravimetric Analysis

https://doi.org/10.5370/KIEE.2021.70.10.1481

이헌경(Heon-Gyeong Lee) ; 윤웅희(Ung-Hui Yun) ; 김진규(Jin-Gyu Kim)

Measuring the accurate activation energy of the insulating materials used in the HVDC environment is an essential condition for reliable prediction of the accelerated life of the insulating materials, so it is important to select various measurement models and analyze them. The activation energy of PE and PP was measured through five measurement methods through TGA, and the reliability was improved by comparing the results of each condition of the heating rate, the degree of conversion and the reaction order. Excluding the conditions that cause errors, the measured activation energy was measured to be 2% lower than the existing measurement methods, and it is thought that it will be used as a useful basic data in the field of reliability

단안 카메라를 사용하는 향상된 SSD 기반의 전방 무인수상선 탐지 연구 Former Unmanned Surface Vehicle Detection Based on Improved Convolutional Neural Network

https://doi.org/10.5370/KIEE.2021.70.10.1488

(Bangqian Ao) ; 김동헌(Dong Hun Kim)

This paper proposes an approach to the real-time implementation of a convolutional neural network (CNN)-based object detector for a former Unmanned Surface Vehicle (USV). The original network VGG-16 of the Single Shot MultiBox Detector (SSD) is first replaced with ResNet-18, as the basic feature extraction network. The classifying network is then redesigned by reducing half of the convolutional kernel numbers, where kernel sizes of 1×1 and 3×3 are mainly used. Simultaneously, a monocular camera installed on the tracking system, is used to calculate the distance and azimuth of the former USV. The experimental results show that the proposed method has advantages of higher accuracy and lower computational complexity, compared with other existing approaches. Therefore, the proposed approach can be efficiently used on real-time tracking systems.

흐름 생산 공정문제를 위한 dueling double Q-러닝 기반 강화학습 기법 연구 Dueling double Q-learning based reinforcement learning approach for the flow shop scheduling problem

https://doi.org/10.5370/KIEE.2021.70.10.1497

김성준(Seong Joon Kim) ; 김병욱(Byung Wook Kim)

Flow shop scheduling is an important optimization problem for operating actual manufacturing facilities. In this paper, we propose a novel flow shop scheduling scheme based on the double Q-learning and the dueling architecture. We designed double Q-learning process using two estimation functions rather than a single estimation function to avoid over-estimation problem. In addition, the adaptation of the dueling architecture, which can provide robust policy estimation performance using both the state function and the advantage function, leading to less-variance and efficient learning process. We conducted extensive simulations of flow shop scheduling using multiple datasets with various scheduling scales. From the simulation result, we observed that the proposed scheme outperforms the existing heuristic and reinforcement learning-based scheduling schemes in terms of the final manufacturing time consumption for various flow shop scales.

딥 러닝에 의한 전동기 기계적 고장 수준 결정을 위한 전동기 진동/전류 데이터 특성 분석 연구 A Study of Vibration and Current Data Characteristic Analysis for Motor Mechanical Fault Level Determination by Deep Learning

https://doi.org/10.5370/KIEE.2021.70.10.1509

한지훈(Ji-Hoon Han) ; 박상욱(Sang-Uk Park) ; 홍선기(Sun-Ki Hong)

In the classic motor fault diagnosis system, a method of analyzing the differences between the normal and collected state signals of the motor to be diagnosed was used and the method can diagnose only the limited situations because the diagnosis is based on the frequency of the mechanical failure. In order to compensate for this, some studies on a system that performs more specialized fault diagnosis through deep learning algorithms were carried out. However, the level of failure cannot be determined because these studies consider only the signals that have a great influence on motor operation. To solve this problem, the characteristics of vibration and current signals are analyzed to develop a deep learning algorithm suitable for fault level determination. The characterized signals are used for fault diagnosis and prediction. Fault diagnosis based on vibration signal is carried out through DT-CNN (Decision Tree Convolutional Neural Network). In addition, it is checked whether the current signal in the initial failure state, which is relatively insensitive to failure, can be classified through a deep learning algorithm. The proposed data utilization performance was evaluated through an induction motor and the analyzed signal-based fault diagnosis system is expected to enable a more precise diagnosis compared to the existing system.

고속철도 신호기계실의 접지전류 진단 및 개선방안에 관한 연구 A Study on the Analysis and Recommendations for Ground Current in the Signal Machine Room of High-speed Rail

https://doi.org/10.5370/KIEE.2021.70.10.1517

윤용기(Yong-Ki Yoon) ; 김성진(Yong-Kyu Kim) ; 고경준(Sung-Jin Kim) ; 박채옥(Kyeong-Jun Ko) ; 김용규(Chae-Ok Park)

Through the construction of high-speed railways and the electrification projects, the railway ground was switched to the common grounding method with the individual(or independent) grounding method. The common grounding method can eliminate the potential difference between the equipment connected to the common grounding line, but the line is used for the path which the return current of a train flows. As a result, it has been confirmed that the impulse surge current invades the signal machine room through the ground wires of the track circuit cable that connects the track circuit devices in the field and the transmitter and receiver in the signal machine room. It was also confirmed that the grounding current that entered the signal machine room affects the grounding current of other equipment in the room. The grounding system inside the signal machine room consisted of the common grounding line buried along the track and a steel frame of the building structure, but the steel frame grounding of the building structure was used as a path for another impulse surge current to enter the room. The ground current that entered the signal machine room continued to adversely affect certain equipment in the machine room, causing the equipment to malfunction or eventually burn out. Therefore, in this paper, we analyze the state of the ground current in the signal machine room and present measures to prevent the impulse surge current from entering the room and suppress the generation of ground circulating current in the room.

실시간 시뮬레이터를 활용한 철도차량 PMSM 제어시스템의 시계열 기반 안정도 추정 Time-series based System Stability Estimation for Railroad Vehicle PMSM Using Real-time Simulator

https://doi.org/10.5370/KIEE.2021.70.10.1526

조환희(Hwan-hee Cho) ; 김재원(Jae-won Kim) ; 김형철(Hyung-chul Kim)

This paper deals with numerical analysis method for system stability, which is applied to the mathematical model of permanent magnet synchronous motor for railway vehicle as one of the application of real-time digital simulation. Specifically, this study deals with bifurcation numerical analysis, one of analytic method to study nonlinear dynamics of a system, for system design or its inspection technique of the system model. XPPAUT is used to analyze the electrical motion of this complex system, so it can introduce theoretical approach to design real-time computing environment based on OPAL-RT for electrification system parts of railroad vehicle model. Within the real-time simulation framework, the paper also provides time-series based system stability estimation by performing statistical processes for auto-regressive model construction. The proposed approach can reduplicate verification process by screen studying of the model for improvement during real-time simulation or further hardware-in-the-loop test system.

유해 아크 정량화를 위한 스마트 진단 프로그램 구현 Implementation of Smart Diagnosis Program for Quantification of Arc Flash Hazard

https://doi.org/10.5370/KIEE.2021.70.10.1535

나경민(Kyung-Min Na) ; 이기원(Kiwon Lee) ; 박철민(Chulmin Park) ; 김형철(Hyungchul Kim) ; 박영(Young Park)

Hazardous arc generated by electrical faults are detected for safety accidents in power facilities. Arc detection has a different measurement method depending on the faults. the arc flash from short circuit or overload is analyzed by voltage and current for diagnosis. However, there is a disadvantage in detecting the arc because of sensitivity to noise before it occur. In addition, detection method based on the photosensor may cause an malfunction by the light around environment. The photosensor with 220 nm can prevent malfunction because it not work in sun of the light. The arc size according to the detection speed is shown as the arc duration. This method reduces error according to the detection speed. However, it is necessary to implement a program capable of determining detection and accuracy determination for quantitative measurement. In this paper, we propose a detection method and program with improved detection speed to detect the arc duration of 10 μs. the error of program is compared with the arc duration generated in real time. In the future, we propose that customized application will be possible according to the factors of arc generation in the electric power field.

SSIM 및 VLSW 알고리즘을 활용한 결측치가 포함된 건물에너지관리시스템 데이터로부터의 에너지소비량 예측에 관한 연구 A Study on Energy Consumption Prediction from Building Energy Management System Data with Missing Values Using SSIM and VLSW Algorithms

https://doi.org/10.5370/KIEE.2021.70.10.1540

(QUAN JUNLONG) ; 신지웅(Jee-Woong Shin) ; 고정림(Jeong-Lim Ko) ; 신승권(Seung-Kwon Shin)

BEMS provide energy forecasting capabilities for effective energy management. Energy consumption prediction requires complete time series data, including missing data sets that may lead to biased results. However, it is a common problem that BEMS data is not measured due to power failure, communication barrier, maintenance and other reasons. Therefore, a solution is required for missing values. The existing methods will affect the results of the prediction model in the case of continuous missing interval or small amount of data. Therefore, this study uses VLSW algorithm which can generate fully learned data with only a small amount of data and SSIM model based on it to study the scheme to improve the prediction accuracy of building energy data set including missing values, and compares the difference with existing models. The results show that the SSIM model has better prediction accuracy than the existing LSTM technology. The concentration range of ASHRAE error level was satisfactory

실측 부하 데이터 기반 경제성 분석을 이용한 도시철도 ESS 최적 용량 산정 연구 Study on ESS Optimal Capacity of ESS based on Economic Analysis of Urban Railroad using Actual Load Data

https://doi.org/10.5370/KIEE.2021.70.10.1548

윤치명(Chi-Myeong Yun) ; 조규정(Gyu-Jung Cho) ; 김형철(Hyungchul Kim) ; 정호성(Hosung Jung)

Abstract - In this paper, method to calculate the maximum capacity of Energy Storage System(ESS) connecting to urban railway substations using characteristics of load patterns is introduced. Optimal capacity of ESS was calculated using economic analysis, Prior to this, the feasibility of the capacity calculation method based on the maximum peak value was shown using the actual data analysis at the morning time when the highest peak occurs. Using the net present value method, which is one of the methods of economic analysis, the method of reducing only the morning peak and the most economical method of reducing all-day are determined and the optimal capacity of ESS is calculated accordingly

AT급전방식 통합접지시스템의 주파수별 접지임피던스 특성 분석 Characteristic Analysis of Transient Ground Impedance with High Frequency Band on the AT Electric Railway Integrated Earthing System

https://doi.org/10.5370/KIEE.2021.70.10.1554

창상훈(Sang-Hoon Chang)

This paper, when lightning current flows into the AT electric railway power feeding system, the ground impedance characteristics according to the length of the buried earth wire and the earth resistivity are analyzed and presented. Due to the increase in accidents caused by lightning and surges in the electric railway operation section, the need to review the grounding impedance of the electric railway integrated earthing system is increasing. The grounding system currently applied to the electric railway operation section has been considered in terms of preventing electric shock to the human body and protecting facilities in the event of a ground fault or short circuit in a commercial power supply of 60[Hz] band. Recently, electronicization of signal and communication facilities installed around railway tracks, high-quality power supply is required. Therefore, the need for technical analysis on ground impedance and transients in high-frequency bands is increasing. The ground impedance is an important factor that distinguishes the characteristics of the AT electric railway integrated earthing system.

DC 1500V 철도차량 급속 충방전 시스템 개발 및 적용시험 Development and applicability test of fast charge/discharge system for DC 1500V railway vehicles

https://doi.org/10.5370/KIEE.2021.70.10.1559

김재원(Jaewon Kim) ; 조환희(Hwanhee Cho) ; 류준형(Joonhyoung Ryu) ; 김형철(Hyungchul Kim)

By using energy storage technology, which is attracting attention as an element technology of the 4th industry, the energy required for train driving can be quickly charged at the station and the regenerative energy generated during braking can be stored as much as possible, so station-fast-charging method has emerged. The fast charge/discharge system, which is a key electronic component of this method, must reflect the characteristics required to be applied to railway vehicles, such as weight and size restrictions due to on-board installation, interface with high power energy storage packs, and energy transfer according to operation patterns. Accordingly, this paper introduces the development case of the first 1500V fast charge/discharge system for railway vehicles and proposes an applicability test method using an actual vehicle that can confirm whether the actually manufactured fast charge/discharge system satisfies the required characteristics of station-fast-charging railway vehicles.

병렬-입력 직렬-출력 구조의 12kW급 다중 공진형 LLC 컨버터의 설계 및 분석 Design and Analysis of 12kW Multiple Resonant LLC Converter with Parallel-Input and Series-Output

https://doi.org/10.5370/KIEE.2021.70.10.1569

김동균(Dong-kyun kim) ; 박찬배(Chan-Bae Park) ; 이재범(Jae-Bum Lee)

Recently, research is actively underway to use energy-efficient hydrogen fuel cells as power sources for railway vehicles. In the past, high DC voltage of inverter was possible by utilizing 3-Level boost converter as a step-up converter in railway vehicle with hydrogen fuel cell. However, conventional 3-Level boost converter has limitations in terms of increasing switching frequencies, which do not reduce the volume of magnetic materials that account for a large portion of the volume of DC/DC converter systems. In this paper, to reduce the volume of the transformer, inductor, capacitor, and heat-sink, ‘multiple resonant LLC converter with parallel-input series-output structures’ operating in resonant and below regions is proposed in high-power and wide-output-voltage range. This paper carried out the optimization design of a 12kW multiple resonant converter and verified it using PSIM for operational analysis, MAXWELL for magnetic field analysis, and ICEPAK for thermal analysis.

무가선트램 구동용 45kW급 마그네틱 기어드 동기전동기의 권선법에 따른 특성 분석 Characteristic analysis according to winding method of 45kW-class MG-PMSM for driving of wireless tram

https://doi.org/10.5370/KIEE.2021.70.10.1580

이형우(Hyung-Woo Lee) ; 이재범(Jae-Bum Lee) ; 임재현(Jae-Hyeon Lim) ; 박찬배(Chan-Bae Park)

In this research, a design model derivation study is conducted to apply the 45kW-class MG-PMSM to the Wireless Tram driving system composed of a conventional induction motor and a mechanical reducer. First, a comparative analysis of electromagnetic characteristics according to a distributed winding and a concentrated winding method among the stator winding methods applied in general PMSM is performed. Next, a characteristic comparison analysis according to the magnetization direction of the permanent magnet of the inner rotor is performed. Finally, a stator winding method suitable for miniaturization and high efficiency of the 45kW-class MG-PMSM is selected

철도차량 보조전원장치용 DC링크단 커패시터의 정전용량 간접 추정 기법에 관한 연구 A study on the indirect estimation method of capacitance of DC link power capacitor for SIV installed under railway vehicles

https://doi.org/10.5370/KIEE.2021.70.10.1588

오효석(Hyo-Seok Oh) ; 최용은(Youn-Eun Choi) ; 김재문(Jae-Moon Kim)

In this paper, techniques for estimating the capacitance was proposed for diagnosing the capacitor state of the DC-Link stage of the SIV installed under the metro line 4 urban railroad vehicle in the metropolitan area. There are various estimation techniques, but considering the situation in which the current flowing through the capacitor and the inverter input current cannot be measured realistically due to the structure of the SIV, two methods based on the BPF and the inverter output line to line voltage were proposed. The estimation methods were verified through simulation, and as a result, it was confirmed that the methods were estimated within an error range of 1.7~3.7% based on the BPF technique and 1.2~1.7% based on the 3-phase inverter output line to line voltage.

역사 내 미세먼지 농도 조절을 위한 강화학습 기반의 공조설비 제어 에이전트 구축 Reinforcement Learning-based HVAC Control Agent for Optimal Control of Particulate Matter in Railway Stations

https://doi.org/10.5370/KIEE.2021.70.10.1594

권경빈(Kyung-bin Kwon) ; 홍수민(Sumin Hong) ; 허재행(Jae-Haeng Heo) ; 정호성(Hosung Jung) ; 박종영(Jong-young Park)

This study developed a reinforcement learning-based energy management agent that controls the concentration of fine dust by controlling the power consumption of energy facilities such as air conditioners and blowers in stations. To apply reinforcement learning, the problem was first defined based on the Markov decision-making process, and a model was developed to predict the concentration of fine dust in history using data correlated with fine dust. Based on the linear compensation function created based on this, the Deep Q-Network (DQN) method was applied to obtain the optimal policy based on the artificial neural network. In the case study, it was confirmed that convergence to the optimal policy was achieved through the learning process, and it was confirmed that the learned agent lowers the fine dust concentration by increasing the power consumption of the air conditioner when the fine dust concentration in the station rises above a certain level

분산전력 제어를 위한 가정용 연료전지 시스템 설계 Residential Fuel Cell System Design for Distributed Power Control

https://doi.org/10.5370/KIEE.2021.70.10.1601

윤용호(Yong-Ho Yoon)

Energy used at home accounts for about 20% of the total energy used in the country, so efficient use of electricity used at home is very important for national energy conservation and reduction of pollution factors. Therefore, among the distributed fuel cells, the household fuel cell (RPG: Residential Power Generator) that is receiving the most attention is expected to be able to solve heating and cooling in the house and use electricity in 10 years without external help. In general, electric energy production always accompanies the production of heat, but the transport of heat for heating is very difficult. In the case of conventional power generation, electricity is generated from large-scale power generation and hot water is received from a boiler at home, whereas the fuel cell system has the advantage of being able to use heat because it produces electricity and heat directly at home. Therefore, the home is the best place to produce and consume heat and electricity at the same time. It is the most ideal place to use the supplied city gas to produce and use heat and electricity using a locally installed small fuel cell power generation system with low exhaust gas and no noise. It could be a household energy system. In this paper, the operation characteristics of a home fuel cell system for distributed power control are verified by designing and manufacturing a fuel cell simulator, a DC/DC step-up converter, and an inverter suitable for a home cogeneration system.

기계식 DC 차단기에 적용 가능한 초전도 벌크 및 와이어 유형의 비교 분석 A comparative analysis of the superconducting bulk and wire types applicable to mechanical DC circuit breaker

https://doi.org/10.5370/KIEE.2021.70.10.1607

박상용(Sang-Yong Park) ; 최효상(Hyo-Sang Choi)

The core technology of the DC grid system is to protect the system in the event of a transient and to cut-off the faults current in a trouble line, quickly. We sat down to analyze to implement the DC breaking technology of mechanical DC circuit breaker on the faster and more safely. However, the mechanical DC circuit breakers have limitations on the opening speed and the components of the break contact. To solve this problem, we applied a superconducting electromagnet to a mechanical DC circuit breaker and proposed a method to reduce the DC Arc energy generated during the breaking operation. In this paper, we proposed the application of superconducting bulk-type magnet and superconducting wire-type electromagnet to the conventional mechanical DC circuit breaker and analysed the breaking characteristic. We designed a mechanical DC cutting-off contact, a superconducting bulk-type magnet, and a superconducting wire-type electromagnet through the Maxwell 3D program. As a result, the Lorentz force was generated between the mechanical DC cutting-off contacts each applied the superconducting bulk-type magnet and wire-type electromagnets. The superconducting bulk-type magnets produced a magnetic force of about 269.3 A/m and the superconducting wire-type electromagnet produced a magnetic force of about 610 A/m affecting DC arc blowing

제주형 태양광 시스템 실증 연구 Outdoor test results of PV system for Jeju application

https://doi.org/10.5370/KIEE.2021.70.10.1611

김기현(Kihyun Kim) ; 구경완(Kyungwan Koo) ; 김필규(Pilkyu Kim)

Jeju island has unique weather such as strong and salty wind. Thus, it is necessary to select stronger PV modules and system components because of Jeju island own harsh weather conditions. To secure safety against harsh weather, more severe tests were carried out for selections of PV. Actually, only test-passed-PV-modules were installed. Lastly, A option of PV mount rotation was added to protect against winds. Herein we will introduce its outdoor test results and guidelines for Jeju application.