• 대한전기학회
Mobile QR Code QR CODE : The Transactions of the Korean Institute of Electrical Engineers
  • COPE
  • kcse
  • 한국과학기술단체총연합회
  • 한국학술지인용색인
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풍력 발전과 부하 사이의 상관성을 고려한 확률론적 전력 조류 해석 기법 제안 Proposal of a Framework for Probabilistic Power Flow that Considers Correlation between Wind Power and Load


이륜경(Ryungyeong Lee) ; 신훈영(Hunyoung Shin)

Due to the increase of the renewable energy and variation of the distributed sources, the power system experience more variability and uncertainty than before. In this paper, we propose an framework for steady-state analysis of power systems using the joint probabilistic information about the wind speeds and loads. Vine copula is employed to capture the the complex dependencies between wind speeds and loads in the multiple regions. In addition, we investigate probabilistic modeling based on the parametric estimation and Wasserstein distance to depict the marginal distribution of wind speed and load. The effectiveness of the proposed method was tested on an IEEE 39-bus system using Python and MATLAB. From the simulation, it was found that the probabilistic power flow method (PPF) that combined vine copula sampling outperforms the deterministic approach and the PPF with random simple sampling in terms of the quantitative risk assessment in the power system.

비선형 자기등가회로 해석을 통한 IPMSM의 쇄교자속 계산에 관한 연구 A Study on the Calculation of Flux Linkage of IPMSM through a Nonlinear Magnetic Equivalent Circuit Analysis


배재남(Jaenam Bae) ; 이성구(Sunggu Lee) ; 김원호(Wonho Kim)

This study describes a method for obtaining the flux linkage, which is the most important parameter in IPMSM. In order to take into account the magnetic flux saturation in the core, the nonlinear analysis approach and the MNA method, which is easily implemented using a computer algorithm, were utilized. In addition, a method for avoiding oscillating solutions when employing the MNA approach was described. In order to determine the flux linkage for each rotor position, the moving winding approach was used to determine the flux linkage for six distinct rotor locations from a single magnetic equivalent circuit. By comparing the MNA-obtained flux linkage to the findings of finite element analysis, the flux linkage's validity was confirmed.

방향성 강판을 적용한 전기자동차용 매입형 영구자석 동기전동기 설계 Design of the Interior Permanent Magnet Synchronous Motor for Electric Vehicles Using Grain-Oriented Electrical Steel


권민수(Min-Su Kwon) ; 임동국(Dong-Kuk Lim) ; 서현욱(Hyeon-Uk Seo)

In this paper, the interior permanent magnet synchronous motor (IPMSM) for electric vehicles (EVs) using grain-oriented electrical steel (GO) is proposed. It was confirmed through the B-H characteristic curve and the B-W characteristic curve that the GO has superior magnetic characteristic compared to the non-grain-oriented electrical steel (NO). In order to maximize the effect of GO, the GO was partially applied to the stator teeth that has a uniform magnetic flux direction through magnetic path analysis of the EV traction motor. It has been confirmed that the output and various characteristics of the motor have improved with the application of GO. In particular, the iron loss was decreased by 44.83% in no-load condition. Moreover, the average torque and the efficiency were increased by 5.26%, 0.29%, respectively and the iron loss was decreased by 42.45% in load condition. The result of this study shows that the partial application of the GO in IPMSM improves the performance of the motor, effectively.

IF 기동방식 센서리스 압축기의 소음 및 진동 저감 제어 Vibration and Acoustic Noise Reduction Control of IF Starting Sensorless Controlled Compressor


박준휘(JunHwi Park) ; 이동희(Dong-Hee Lee)

This paper presents a simple mechanical vibration and acoustic noise reduction of IF(current-frequency) starting sensorless controlled compressor. The adopted compressor is controlled by the sensorless estimation using back EMF observer in the normal speed range. In order to increase the speed up to normal sensorless speed range, the IF open-loop starting method is used. At the IF starting, the speed variation from the fluid load makes a mechanical vibration and acoustic noise. In order to reduce the mechanical vibration and acoustic noise, a simple variable torque slope with initial rotor position estimation method is proposed in this paper. The proposed method uses an initial rotor position estimation than a conventional rotor alignment method. And, the torque reference slope according to the increased open-loop speed is changed by the hysteresis error between the open-loop reference speed and the estimated speed. Because of the initial rotor position and the variable current according to the speed can reduce the collision of the compressor at standstill and low-speed region. Consequently the mechanical vibration and acoustic noise can be reduced. The proposed simple variable IF starting method is verified 2.2kW IPMSM driven HVAC(Heating, Ventilation & Air conditioning) compressor. Experimental results shows the reduced vibration and acoustic noise at the starting to normal speed range.

자기 공진형 무선전력전송 시스템 송신기의 개수에 따른 자기장 안전성 평가 Evaluation of Magnetic Field Safety in Wireless Power Transfer System via Magnetic Resonance according to the Number of Transmitters


안지수(Ji-Su An) ; 소평호(Pyung-Ho So) ; 신강인(Gang-In Shin) ; 이병희(Byoung-Hee Lee)

Various studies are being conducted to commercialize the magnetic resonance type wireless power transfer technology. In the magnetic resonance type wireless power transfer technology, a magnetic field is formed when power is transmitted. In addition, the range and strength of the generated magnetic field are varied according to the number of transmitters and the level of transmitted power. The generated magnetic field during power transmission may affect the human body. In this paper, the strength of the magnetic field according to the distance change was compared for the case of one transmitter and two transmitters with the same received power condition. Moreover, the safe range from magnetic fields generated during power transmission was confirmed based on international standards.

절연형 고전력 밀도 통신 DC-DC 컨버터 스테이지용 자기 전력 부품 설계 분석 및 제조 Magnetic Power Components Design Analysis and Manufacturing For an-Isolated High-Power Density Telecom DC-DC Converter Stage


아메드하싼오킬리(Ahmed H. Okilly) ; 백제훈(Jeihoon Baek)

The adoption of 5G technology in communications necessitates an increase in supply power factor and conversion efficiency to improve power quality. A two-stage AC-DC power supply with a power factor correction (PFC) stage and a DC-DC converter stage is the best option for supplying power to these loads, with the PFC stage's optimized design offering a high power factor and the DC-DC stage's optimized design offering low voltage and current stresses, low thermal and conduction power losses and then high conversion efficiency. Thus, an optimized design and manufacturing technique for the magnetic components, including the high-frequency (HF) transformer and inductors are proposed in this paper for the telecom power supply second stage to offer operation with zero voltage switching (ZVS), improve conversion efficiency, reduce voltage and current stresses, and maintain the load voltage and current ripple contents at the standard levels. Loss analysis is performed on all designed magentic power components. The performance of the developed converter with the optimized design components is investigated using PSIM simulations and experimental verification.

3상4선식 컨버터의 독립전력제어 기반 능동수명제어 알고리즘 Active Thermal Control Algorithm with Independent Power Control Based on Three-phase Four-wire Converter


응웬 민 호앙(Minh Hoang Nguyen) ; 곽상신(Sangshin Kwak)

Along with using renewable energy sources such as photovoltaic (PV), wind, and biomass, the power system structure has evolved and grown more complex in recent years. As a crucial part of power distribution, the three-phase converter plays a significant role; nevertheless, this does not account for the fact that various phase legs may experience different aging conditions. This study offers an active thermal control (ATC) concept for a two-level, three-phase, four-wire converter with balance circuit in order to delay the failure of the aged leg and the entire converter. The first ATC approach using the model predictive control (MPC) strategy is investigated to regulate the output current and balance the capacitor voltage. A modified cost function is proposed to improve the capacitor voltages balancing control capability. Additionally, the second ATC approach using a carrier-based pulse-width-modulation (CBPWM) method based per-phase voltage and current control is introduced. The achieved simulation and experiment results of both CBPWM and MPC schemes are presented to verify the performance of the ATC based per-phase power control for the two-level three-phase four-wire converter with balance circuit.

Rosen type 압전 변압기를 적용한 단락 사고 신호 검출 방법에 관한 연구 A Study on the Signal Detection Method of Short Circuit Accident Applying Rosen Type Piezoelectric Transformer


안종수(Jong-Su An) ; 김태규(Tae-Kue Kim) ; 곽군평(Gun-pyoung Kwak)

In short circuit protection applications, a protection system with a current limiting circuit and a relay has been developed recently. In this system, the circuit can be configured simply by changing the relay contact. However, this system has disadvantage limited load power by parallel resistor for relay operation. In this paper, we propose a short circuit accident prevention system using a piezoelectric transformer to solve the problem of system load power limitation. In the event of a short circuit, we analyze the possibility of harmonic rejection and output voltage detection through a piezoelectric transformer. Through this, we studied the applicability of the short circuit accident preventi on system of the piezoelectric transformer.

Ti-Zr 합금 타겟을 사용하여 아크 이온 플레이팅법으로 형성된 TiZrN 박막의 특성 Properties of TiZrN thin Film Formed by Arc Ion Plating Method using Ti-Zr Alloy Target


정운조(Woon-Jo Jeong)

80Ti-20Zr, 50Ti-50Zr, 20Ti-80Zr [wt%] alloy composition was designed to develop a Ti-Zr alloy target that can exhibit various properties depending on the composition ratio. And the vacuum arc melting process was established and finally, a 100[mmφ] Ti-Zr alloy ingot was developed. Then, using the Ti-Zr alloy target of these three compositions, the AIP process was performed while changing the bias voltage to form a TiZrN thin film with a thickness of about 3[μm]. The TiZrN thin film was able to achieve an adhesion force of 60[N] or more and a high hardness of 1,500[Hv] under the 100[V] bias condition, and various characteristic changes were considered by changing the Ti and Zr composition of the alloy target.

비가시권 송전선로 점검드론 시스템 개발 Development of a Beyond Visual Line of Sight Drone System for Inspection of Transmission Lines


류서현(Seo-Hyeon Ryu) ; 박준영(Joon-Young Park) ; 김석태(Seok-Tae Kim) ; 이재경(Jae-Kyung Lee) ; 고병성(Byung-Sung Ko) ; 우정욱(Jung-Wook Woo)

In this paper, we proposed a Beyond Visual Line Of Sight(BVLOS) drone system for inspection of transmission lines. As drone technology advances, drones are replacing dangerous tasks in the electric power industry. According to this trend, Korea Electric Power Corporation has developed the automatic inspection drone system for transmission lines. This system targeted inspection of transmission lines in the visible area. Since the transmission line is mainly located in mountainous area, the drone frequently enter the invisible area. In order to inspect multiple transmission lines with the existing system, frequent movement for drone takeoff and a lot of preparation time are required. To overcome this problem, we upgraded the existing system to inspect BVLOS transmission lines. For BVLOS flight, laws and regulations must be observed. Therefore, essential functions were derived from laws and regulations, and these functions were developed to be suitable for inspection of transmission lines. Finally, our system was verified through special flight approval from the Ministry of Land, Infrastructure and Transport. Through the new transmission line inspection drone system, the multiple transmission lines can be efficiently inspected at once.

유효한 키포인트 증식 기반의 가려진 사람의 재식별 Valid Keypoint Augmentation based Occluded Person Re-Identification


김세준(Sejun Kim) ; 강성재(Sungjae Kang) ; 최요민(Hyomin Choi) ; 김성수(Seong Soo Kim) ; 서기성(Kisung Seo)

Occluded person re-identification is a challenging task which aims to search for or distinguish the specific person as human body is occluded by obstacles or other persons or by oneself. Some recent State of the art works which adopt transformer and/or pose-guided methods improve the feature representation and performances, but there is a room to enhance them in both representation and heavy structure. In this paper, we suggest to efficiently improve the transformer-based Re-ID method for the occluded person as follows. First, in data augmentation to improve Re-identification performance, instead of deleting an arbitrary area, only the part containing the keypoint feature of a person is deleted for effective learning in occlusion. Second, a consistency loss between global and local features of a body part is proposed for improving the discrimination to recognize the identical person. We compare the mAP and Rank-1 performances of our approach and various existing methods on the Occluded-Duke dataset. Experimental results show that our proposed model outperforms the competitive methods.

WebGPU를 이용한 AES 알고리즘 가속화 Accelerating AES Algorithm using WebGPU


남현우(Hyunwoo Nam) ; 박능수(Neungsoo Park)

Modern web browsers use HTML5 to implement native web applications. However, it is hard to directly utilize the GPU for general-purpose computation in a web browser. Even though standard technologies such as WebGL and WebCL are applicable to use the GPU in a web browser, they can be applied only in the 3D graphics field or cannot due to the discontinuation of development. Recently major web browser vendors are developing a WebGPU standard for general-purpose computation. This paper presents a method to implement a Web application, including general-purpose computing, with WebGPU and SPIR-V. The computation-communication overlap technique is also applied to improve the overall performance. Experimental results showed that the web application performance using WebGPU increases as the size of encrypted data increases. It showed that WebGPU-based parallel computing could be applicable for web applications that require high-performance computation.

건물의 에너지 사용량 예측을 위한 하이브리드 모델 연구 A Hybrid Model for Predicting Power Consumption in Buildings


이태규(Tae-Kyu Lee) ; 김정욱(Jeong-Uk Kim)

The purpose of this study was to predict energy consumption of a building using a hybrid model. A hybrid model proposed to complement the physical energy model and the data-driven model. Hybrid model has advantage of being able to predict power consumption well compared to the existing models. According to the experimental results, a hybrid model showed superior performance compared to the comparative models that predicted based on the degree day and using TRNSYS. A hybrid model showed about 6.5% better predictive performance rather than the TRNSYS simulation, and it showed excellent predictive performance regardless of the ratio of the training dataset in comparison with the cooling degree-based predictive model. In the future, through in-depth study, a hybrid model would be calibrated, and it will be used in the implementation services that predict energy savings and suggest the optimal savings plans.

문자 인식을 이용한 격자무늬 추적 로봇의 자율주행 방법에 관한 연구 A Study on an Autonomous Driving Method for a Robot that Tracks Grid Pattern using Character Recognition


김정주(Jung-Ju Kim) ; 김동진(Dong-Jin Kim) ; 구경완(Kyung-Wan Koo)

In the indoor space where we live and use, various indoor signs such as floor information, room name, and walking guidance display are installed for the convenience of users. Humans can use this visual information(character/symbol information) to determine their current location and find their destination. In this study, we propose an autonomous driving method for a grid-pattern tracking robot that mimics human visual intelligence. The grid-pattern tracking robot recognizes characters from images acquired while driving, identifies the current location, plans a route to the destination, and performs autonomous driving.ㅍ

다구찌기법 기반 25.8kV 친환경 가스개폐기 최적 절연설계 Optimal Insulation Design of 25.8kV Environment-friendly Insulated Switch Based on Taguchi Method


유련(Lyun Yu) ; 김영문(Young-Moon Kim) ; 안길영(Kil-young Ahn) ; 김영근(Young-Geun Kim) ; 조해용(Hae-Yong Jo)

A underground electrical switch is a medium voltage switch used in the distribution network system for stable power supply. Until now, SF6 gas insulated switch has been mainly applied, but many researches are underway to expand and distribute eco-friendly gas insulated switch using dry-air instead of SF6 gas to reduce greenhouse gas. Design process for components such as insulation and shield parts in order to secure the optimized insulation performance of eco-friendly gas insulated switchgear was studied in this paper. An orthogonal table with S/N (Signal to Noise) ratio values was obtained using the Taguchi method and electric field analysis. In relation to the data of the orthogonal table, the combination of design element parameters corresponding to the optimal condition was obtained. Based on this methodology, the improvements in the optimized model are compared and analyzed.

저압직류차단기의 소전류 영역 차단특성과 성능향상을 위한 연구 A Study on the Characteristics and Breaking Performance Improvement in Small Current Region of a Low Voltage Direct Current Circuit Breaker


박우진(Woo-Jin Park) ; 안길영(Kil-Young Ahn) ; 김영근(Young-Guen Kim) ; 조해용(Hae-Yong Cho)

A low voltage direct current(DC) circuit breaker is an electrical protection device that interrupts the abnormal fault currents which result from the over-loads or short-circuits in a low voltage(less than 1,500Vdc) power distribution line. Recently, as interests in renewable energy fields(such as photovoltaic and energy storage systems) have increased, research on DC circuit breakers for system protection is also being actively conducted. However, breaking the fault current in DC system is considerably difficult even small current region since the DC does not have current zero point such as in AC. When a short circuit occurs, a fault current flows between contacts of a DC circuit breaker even though they are separated by the protective control system. Arc voltage between contacts of the circuit breaker should generate as high as possible during breaking phase. High arc voltage could lead the fault current of the circuit to zero so that arc plasma is eliminated. Based on this behavior, arc extinction system of a DC circuit breaker should be designed to effectively increase the arc voltage during current interruption period. In this paper, the characteristics of DC breaking specially in small current region were confirmed through several types of current breaking experiments and result analysis, and a method to improve performance of DC breaking in small current region was presented, and experiments were carried out to verify the validity of the method