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

혼합 정수 선형 계획법 기반의 최적 경제 급전을 활용한 분산형 열병합 발전원의 송전선로 건설비용 회피 편익계산 Calculating the Benefit of Distributed Combined Heat Power Generators from Avoiding a Transmission Expansion Cost by Solving a Mixed Integer Linear Programming

http://doi.org/10.5370/KIEE.2019.68.4.513

권욱현(Wook Hyun Kwon) ; 박용기(Yong-Gi Park) ; 노재형(Jae Hyung Roh) ; 박종배(Jong-Bae Park) ; 이두희(Duehee Lee)

We calculate the benefit of distributed combined heat power generators from avoiding a transmission expansion cost by building distributed generators near electricity demand centers. We determine a transmission expansion plan by solving a mixed integer linear problem, where we modify capacities of existing transmission lines and build new transmission lines. We calculate the benefit by comparing the sum of generation and transmission expansion costs with or without distributed generators through two simulation frames. In the first frame, for the current demand, we substitute existing distributed generators for non-distributed generators and measure an additional cost to balance the generation and demand. In the second frame, for increased future demand, we compare the cost to invest only in distributed generators to the cost to invest only in non-distributed generators. As a result, we show that the distributed generators have at least 5.8 won/kWh of the benefit from avoiding the transmission expansion cost.

슬롯 수에 따른 100MW급 권선형 동기발전기 발전특성 및 운전특성 비교 Operation and Generation Characteristic of 100MW-Class Wound Rotor Synchronous Generator According to Number of Slots

http://doi.org/10.5370/KIEE.2019.68.4.523

김창우(Chang-Woo Kim) ; 박요한(Yo-Han Park) ; 최장영(Jang-Young Choi)

This paper deals with a wound-field synchronous machines(WFSM), with an electromagnet on its salient rotor, as an alternative to a permanent magnet in the rotor. We then examine the power performance characteristics, loss characteristics, V-curves and large short-circuit ratios for a large-scale synchronous generator, considering the leading and lagging operations, based on the finite-element method. We predict the performance of a 100MVA-class generator based on the operating range for a constant short-circuit ratio. At the last, We compared with the electromagnetic characteristics of three model according to number of slots.

운전 전압 조건에 따른 고하중 대차 견인용 유도전동기의 출력 및 손실 특성 해석 Characteristic Analysis on the Output Power and Power Losses of Induction Motor for Large-Load Bogie Traction according to Operating Voltage Condition

http://doi.org/10.5370/KIEE.2019.68.4.532

신경훈(Kyung-Hun Shin) ; 박동빈(Dong-Bin Park) ; 최장영(Jang-Young Choi) ; 조한욱(Han-Wook Cho)

In this paper, we analyze the electromagnetic performance of induction motors for large-load bogie traction according to the input voltage. The performance of the induction motor is numerically represented on the basis of the sinusoidal voltage and the pulse voltage input according to operating conditions, and their advantages and disadvantages are analyzed. Based on analysis results, we derived the traction curve and the electromagnetic performance map considering the input voltage and the operating condition and confirmed that the control method applied in this study has excellent performance.

고효율 4-레벨 NNPC 인버터를 위한 커패시터 전압 제어 알고리즘 High Efficient Four-Level NNPC Inverter with Capacitor Voltage Control Algorithm

http://doi.org/10.5370/KIEE.2019.68.4.540

김병준(Byungjun Kim) ; 전은수(Eun-Su Jun) ; 노찬(Chan Roh) ; 곽상신(Sangshin Kwak)

Four-level NNPC (Nested Neutral Point Clamped) inverters have fewer components compared to other 4-level inverters and can operate from 2.4 kV to 7.2 kV without the need for additional switching devices. The 4-level NNPC inverter outputs the final switching signal in consideration of the output current and the capacitor voltage state, since the flying capacitor voltage of each phase should be controlled to Vdc / 3 and normal control is possible. A carrier based pulse width modulation (CBPWM) method is used meanwhile, a new capacitor voltage control algorithm is proposed to reduce the switching loss for the conventional capacitor voltage control. In this paper, a 4 - level NNPC inverter was designed for experimental setup was made for the experiment. The validity of the capacitor voltage control algorithm is verified through experimental results.

Filtered Vacuum Arc법으로 WC-Co계 합금 표면에 형성된 DLC 박막의 구조적 특성 연구 A Study on the Microstructural Properties of DLC Films Deposited on the WC-Co Alloy by Filtered Vacuum Arc Method

http://doi.org/10.5370/KIEE.2019.68.4.547

강병모(Byeong-Mo Kang) ; 정운조(Woon-Jo Jeong)

In this study, DLC films were deposited on the cobalt cemented tungsten carbide(WC-Co) substrate adopting the filtered vacuum arc(FVA) technique at different substrate bias voltages and various cobalt content. As a result of Raman analysis, the spectra from all samples in this study have similar shape, with a broad skewed peak centered at approximately 1,550[cm-1], which is the characteristic of the diamond-like structure. Each spectrum was decomposed into two Gaussian line curves, one at the lower wave numbers between 1,322[cm-1] and 1,329[cm-1](D peak) and the other at the higher wave numbers between 1,565[cm-1] and 1,570[cm-1](G peak). However, we could not find any change of Raman-shift. According to XPS, as the cobalt content increased, sp3 ratio was decreased. This effect can be inferred that the cobalt binder suppress diamond nucleation and subsequent growth of diamond.

모노폴 안테나에 커플링되는 EMP에 의한 LNA(Low Noise Amplifier)의 민감성 분석 Analysis of LNA(Low Noise Amplifier) Susceptibility by EMP Coupled to the Monopole Antenna

http://doi.org/10.5370/KIEE.2019.68.4.553

방정주(Jeong-Ju Bang) ; 허창수(Chang-Su Huh)

In this paper, the output waveform of EMP coupled to 10 MHz monopole antenna analyzed by simulation, and the susceptibility of LNA(Low Noise Amplifier) was evaluated. The waveform of EMP coupled to the monopole antenna is a 10 MHz damped sinusoidal waveform, and the peak voltage is about 22 kV. The susceptibility of LNAs was evaluated using the 10 MHz damped sine wave generator. DFR(Destruction Failure Rate) was measured to investigate the susceptibility of LNA. The susceptibility level of LNA was assessed by voltage of damped sine wave. The voltage of destruction threshold is 71 V and 107.5 V respectively. The coupling voltage is higher than the destruction threshold of LNAs. Therefore, the communication system can be damaged by EMP. It is necessary to apply the protection device to the communication system. Based on these results, susceptibility of LNA can be applied to a basic data for applying the protection device to the communication system against EMP.

다중 퍼지 예측시스템을 이용한 월별 전력부하 예측 Monthly Electricity Load Forecasting Using a Multiple Fuzzy Forecasting System

http://doi.org/10.5370/KIEE.2019.68.4.558

방영근(Young-Keun Bang) ; 이철희(Chul-Heui Lee) ; 박하용(Ha-Yong Park)

This paper presents design methods of a fuzzy forecasting system to forecast the monthly peak electricity load data in south korea. In the proposed forecasting system, multiple fuzzy predictors are combined by parallel so that each predictor can perform suitable forecasting for corresponding to segmented data set. To segment the original peak electricity load data, data interpolation and trend analysis methods are used. The segmented data set is used as input data, to design each predictor, the TSK fuzzy logic model and the least square method are used for linguistic rule base and parameter identification. Also the K-means clustering algorithm is used to generate suitable fuzzy sets and tune their membership function. Using monthly peak electricity load data from Feb. 2009 to Feb. 2018 in south korea, in simulation section, the forecasting performance and advantage of the proposed system are verified and explained.

지향각속도 제한을 고려한 복합 유도법칙 New Composite Guidance Law with Look Angle Rate Constraint

http://doi.org/10.5370/KIEE.2019.68.4.566

김태훈(Tae-Hun Kim) ; 박봉균(Bong-Gyun Park)

This paper proposes a new composite guidance law that can intercept moving targets and satisfy look angle rate constraint. In order to obtain the composite guidance law, we first develop a new look angle rate control guidance law which can maintain the maximum look angle rate limitation. And then, we propose the composite guidance scheme on the basis of the look angle rate control guidance and the proportional navigation guidance. To investigate the capturablity and characteristics of the proposed guidance, we also derive closed-form solutions and perform various numerical simulations. The proposed composite guidance only requires the line-of-sight rate, closing velocity, and missile's speed, thereby easily implementing in practical homing missiles.

표면근전도 신호를 대상으로 근피로도 측정 매개변수들의 결정성과 민감성 분석 Analysis of Muscle Fatigue Determination and Sensitivity for Parameters to Detect Muscle Fatigue from Surface EMG Signals

http://doi.org/10.5370/KIEE.2019.68.4.573

이진(Jin Lee)

The purpose of this study is to compare the performance of seven fatigue detection parameters, MNF(mean frequency), MDF(median frequency), FBR(frequency band ratio), SMR(spectral moment ratio), ZCF(zero-crossing frequency), TUF (turn frequency) and SPF(spike frequency), based on muscle fatigue determination and sensitivity. Surface EMG signals(a total of 198 signals) were recorded in biceps brachii muscle with isometric 20%, 50% and 80% MVC contractions from eleven subjects. The parameters were calculated from the signals and the resulting fatigue curves were compared considering fatigue determination performance and fatigue sensitivity performance. Results of this study suggest that SMR is more reliable and sensitive parameters than others for differentiating muscle fatigue level from surface EMG signal obtained by isometric voluntary contraction.

저압배전계통의 SPD 안전설치를 위한 오결선 검출회로와 소프트웨어 알고리즘의 개발 Development of the Miswiring Detection Circuit and Software Algorithm for Safe Installation of SPDs for Low-Voltage Distribution System

http://doi.org/10.5370/KIEE.2019.68.4.579

이영준(YoungJun Lee) ; 이영삼(Young Sam Lee)

In this paper, we propose a detection circuit and a software algorithm to prevent wrong wiring connection of CT2 SPD. Most of domestic low-voltage consumers are supplied from the KEPCO with TN-C grounding system, but the load facilities are mainly based on TT grounding system. Therefore, in order to prevent damage caused by lightning, most SPDs use a CT2 type SPD that can be suitable for both TN-C and TT grounding. There is no separate bus-bar for the outdoor electric enclosures such as CCTV, so it is difficult to distinguish between the phase and neutral cable. In this environment, the phase and the neutral cable may be connected in reverse by mistake of the installer. However the status indicator of SPD is displayed as normal even under the inverse wiring condition. If a surge enters in this condition, the SPD will be damaged and the electricity supply may be disrupted. The proposed detection circuit and software algorithm are expected to be useful for preventing miswiring of SPD.

3상 유도전동기 운전중 한상의 결상에 따른 운전 특성 해석 Analysis of Operation Characteristics by Single Phase Loss During Operation of Three Phase Induction Motor

http://doi.org/10.5370/KIEE.2019.68.4.587

김종겸(Jong-Gyeum Kim)

Induction motors are failing due to various causes. The biggest factor in electrical failure is due to overheating. Single phase loss in which one phase of the three phases is suddenly opened is included in the occurrence of a major failure in an electrical failure. The generation of a single phase loss can overheat the stator winding due to an increase in current, which can lead to burnout. It also affects torque, so it can deliver large torque ripple to the shaft. Therefore, it is very important to clarify what kind of problem exists when a single phase loss of the induction motor occurs. In order to compare the change of operation of induction motor during normal operation and single-phase loss operation, the rotational coordinate system theory was introduced. In this paper, changes in current, electric power, and torque were analyzed when single phase loss occurred due to the power source side of the induction motor being operated normally. It was found that the existence or absence of current and the pulsation of the magnetic flux at any phase specified during one-phase loss operation greatly affects the torque and affects the electric power.

초전도 코일 적용으로 인한 DC 차단기의 차단 용량 증대 Extension of Cut-off Capacity of DC Circuit Breaker due to Superconducting Coil Application

http://doi.org/10.5370/KIEE.2019.68.4.593

최혜원(Hye-Won Choi) ; 최효상(Hyo-Sang Choi)

We proposed a current Interruption type DC superconducting circuit breaker(I-DC SCB), a protection device that combines the current limiting technology of a superconductor with the cut-off technology of circuit breaker. Unlike existing protective devices, the current I-DC SCB is a device that combines two protection functions, notably improving failure probability and operational reliability. It is also applicable to all DC systems, such as HV, MV, and LVDC, due to the ease in capacity increase. The 100 kV I-DC SCB was designed after taking into account the actual power system conditions, followed by an analysis of the transient characteristics and the breaking range of the limiter. The results of the analysis showed that the I-DC SCB had a fault current limit of about 75% at the rated voltage, and completed the cut-off operation within about 20 ms.

IEC 62109에 의한 태양광인버터 성능 및 안전성평가 Performance and Safety Evaluation of PV Inverter by IEC 62109 Standard

http://doi.org/10.5370/KIEE.2019.68.4.598

홍경진(Kyung-Jin Hong)

The supply of new and renewable energy facilities has been increasing rapidly, especially in the PV power sector. In addition to the spread of PV modules and inverters, it is urgently required to ensure safety as well as performance. In developed countries such as Germany, Japan and the USA, technical standards on safety are applied to ensure safety of the photovoltaic industry to be. Currently, technical standards for securing the safety of PV inverters are adopted by IEC, while advanced countries apply technical standards for securing safety and are certifying the safety of the solar products in accordance with the IEC standard. However, in Korea, the technical standards for the performance evaluation of PV modules and inverters are applied, but the safety technical standards are not applied. Especially, in case of PV inverter, it has certification standard of small size solar inverter(less than 10kW) and inverter of medium and large size solar power generation(more than 10kW~250kW). Examination of the contents of each test item is composed of tests to identify performance characteristics of inverter such as insulation performance, protection function, normal characteristics, transient characteristics, external accidents, and environmental tests. Therefore, in this paper, we will examine the precise technical standards and test methods for the standardization of IEC 62109, which is becoming a standard required for overseas certification such as CE and UL, focusing on the protection and safety of users.