Mobile QR Code QR CODE : Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

ISO Journal TitleJ Korean Inst. IIIum. Electr. Install. Eng.

시뮬레이션을 통한 455nm 청색 LED 여기 광원과 형광체 조합에 따른 연색특성 변화 연구 Simulation Study on Variations of Color Rendition Properties According to Combination of 455nm blue LED and Phosphor Emission Spectra

Hyeong-Seob Jo ; Jong-Oh Kim ; Uh-Chan Ryu

Recently, studies have been performed regarding to various methods of improving color rendering properties of white LEDs by mixing warm white (WW) and cool white (CW) or red (R), green (G), blue (B), and yellow (Y) LED spectra. However, the previous researches have been insufficient in presenting maximum optical characteristics over all correlated color temperature (CCT) ranges or representing recently suggested evaluation methods of color rendering properties. In this paper, color rendering properties including the recent methods at all CCTs will be investigated through simulation combining various kinds of phosphors excited by a 455nm blue LED. For evaluating CRI values, general and special color rendering indices (Ra and R9∼14), general color quality scale (Qa), fidelity index (Rf), and color gamut (Rg) will be examined and compared by root mean square (RMS) values. 2-phosphor combination with a blue LED resulted in Ra≥95, R1∼14≥75, and Qa≥90, 3-phosphor in Ra≥98, R1∼14≥75, and Qa≥97, and 4-phosphor in Ra≥94, R1∼14≥71, and Qa≥90.

G13캡 전원 직결형 LED램프의 안전성 향상에 관한 A Study on Safety Improvement of Directly Powered G13 Cap LED Lamp

Jin-Tai Kim ; Chung-Hyeok Kim

Through this study, safety issues have been identified when direct AC type LED lamp is installed in external converter type LED lamp, fluorescent lamp, ballast compatible LED lamp. Safety improvement will be proposed on directly powered G13 cap LED lamp.

3kW급 소형 풍력발전용 이중고정자형 발전기의 코깅토크 저감을 위한 고정자 치조합 설계 Stator Teeth Pairing Design for Cogging Torque Reduction of Dual Stator Type Generator for 3kW Small Wind Turbines

Myeong-Jun Gwak ; Jung-Rang Seo ; Tae-Uk Jung

Dual stator type generators have excellent output per unit volume and can generate high efficiency in a wide operating range based on high voltage at low wind speed. The dual stator type generator can minimize the cogging torque generated by the two inner and outer generators through the mutual displacement of the stator or the permanent magnet. However, this method has a disadvantage of lowering the output and efficiency of the generator. Therefore, this paper presents a design method applying stator teeth pairing to reduce cogging torque of dual stator type generators. The proposed method is to design the width of inner stator teeth and the width of outer stator teeth to be different from each other. To verify the validity of this paper, we present the results of 2D finite element analysis and verify the validity of this paper.

에너지저장장치 운전 계획을 위한 전력 사용량 패턴 분류 알고리 Pattern Classification Algorithm for Electricity Usage Patterns for Planning the Operation of Energy Storage System

Young-Il Kim ; Sung-Man Choi ; Min-Kyu Baek ; Bok-Deok Shin

Prediction of electricity usage patterns plays an essential role in managing the usage efficiently. The prediction needs to be done sophisticatedly and accurately in order to operate energy storage system efficiently since the accuracy of prediction has a big effect on the storage operation plan. In recent years, machine learning-based solutions are being developed because regression analyses have limits when electricity usage has irregular patterns. As the accuracy of machine learning-based predictions depends on the quality and quantity of data to be learned, however, preprocessing process that classifies and labels the usage pattern is important. In this study, we suggest a PCL (Pattern Classification Labeling) algorithm to improve the machine learning-based prediction. It analyzes an actual load data to compare the PCL algorithm with K-means algorithm that has been used widely. In the result, PCL algorithm shows less error rate than K-means algorithm does by 12.2%.

배전자동화시스템에서 배전선로 고장발생 인지 방법 A Method to Detect Faults on the Distribution Feeder in the Advanced DMS

Jihui Hwang ; Seongil Lim

When a fault occurs in the distribution feeder, the distribution system operator recognizes the state of the system and makes a restoration plan to deal with the fault based on alarms delivered to the ADMS(Advanced Distribution Management System). It is difficult to rapidly determine the system operating condition because numerous alarms due to the fault are generated at the same time. This paper presents a method to detect a fault on the distribution feeder considering the situation where a lot of alarms are delivered to the ADMS. The proposed method supports distribution system operators to intuitively determine the situation by analyzing and filtering the characteristics of field alarms. By processing alarms sequentially and designing different processing algorithms according to their characteristics, faults can be rapidly determined. To verify the feasibility of the proposed fault diagnosis method, case studies have been performed in various fault conditions.

재생에너지 출력제한 최소화 에너지 믹스 및 저감 방안 Minimization of Renewable Energy Output Limits and Reduction Methods

Chang-Woo Lee ; Yeong-Hwan Kim ; Se-Ho Kim

The renewable energy resources have been attracting public attention because of environment problems like global warming effect. Although the renewable energy has been constructed rapidly over the world. This uncontrolled power sources can cause a problem of grid stability such as unbalance situation between electricity supplement and demand load. Especially, variability of renewable energy can negatively affect to power system network and increasing penetration of renewable energy causes penetration limit of renewable energy. The grid operator has curtailed that to maintain stable grid conditions. From this view point, this thesis was analyzed for wind and solar power generation comparing with power load to minimize the limitation of grid connection clean energy. The thesis presents curtailed renewable energy depend on the ratio between wind and solar power generation. In addition, the application of energy storage system devices was also considered to maximize the use of renewable energy.

빅데이터를 활용한 하절기 평일의 시간대별 전력부하예측 신경망 모형 Modeling of Artificial Neural Network Based on Big Data for the Prediction of Hourly Load in Summer Weekda

Young-Jin Nam ; Ha-Hyun Jo

In this paper, The MLP model was developed to predict the weekday of August during the 18 year summer season. The MLP model reflected a variety of factors affecting hourly loads: weather·Calendar information and big data. In addition, two MLP models were constructed, each using ELU and ReLU as an activation function. In order to evaluate the predictive performance, out of sample forecasting was performed. The results showed that the average MAPE for the ARIMA-X model as a benchmark was 3.88. However The MLP model 1 and The MLP model 2 was 2.69 and 2.49, respectively. so the artificial neural network model reflecting weather·calendar information and big data was more predictive performance than time series model

실리콘 기판 상 바나듐 이산화물 및 알루미늄 질화물 이종 구조 박막에서의 근적외선 레이저 펄스 기반 가역적인 전류 스위칭 Reversible Current Switching Based on Near-Infrared Laser Pulses in VO2/AlN Heterostructure Thin Film on Si Substrate

Jihoon Kim ; Yong Wook Lee

In this paper, we demonstrated a reversible current switching in a two-terminal device based on a vanadium dioxide(VO2) and aluminium nitride(AlN) heterostructure thin film grown on a silicon(Si) substrate using near-infrared laser pulses. The fabricated VO2/AlN device has a phase transition temperature ∼10K higher than conventional VO2 devices grown on sapphire substrates. Current switching operation of up to 50mA was possible at various pulse repetition rates in the device with smaller dimensions owing to the increased phase transition temperature, and the average switching contrast was calculated as ∼9634. In particular, the average rising time of the switched current was measured to be ∼36ms, and the falling time was less than 10ms, which is a significantly improved result. Due to the high phase transition temperature and fast switching response, the fabricated device is expected to be beneficially applied to laser-assisted current switching.

기동중 단상 결상시 3상 유도전동기의 동작 특성에 관한 연구 Study on the Operational Characteristics of Three-Phase Induction Motor by Single-Phasing During Start-Up

Jong-Gyeum Kim

Induction motors cause a failure due to electrical and mechanical causes. The most significant cause of electrical failure is due to overheating due to high current. Induction motors generate high currents at start-up, but become very low as the rotational speed increases. If the current does not decrease as the rotational speed increases, it may act as an electrical stress on the winding. A single-phasing in which one phase of the three phases is suddenly opened. The generation of single-phasing can overheat the stator winding due to a sudden increase in current, if this condition persists, the winding will overheat and eventually be burned out. Further, since the rotational speed is transferred to the braking region and the rotor is restrained, the normal torque can not be ensured. Therefore, it is very important to analyze what problems occur when single-phasing exists in an induction motor. In this study, we analyzed the magnitude and the torque change of voltage, current, power, power factor appearing to the induction motor when single-phasing occurred from three phase power source during startup. As a result of the analysis, it was found that the current generated during single-phasing is higher than the normal start-up current, and if it is not removed, it may persist and lead to overheating. And it can be seen that normal torque can not be secured because the forward torque and the reverse torque are repeatedly operated by the restraint of the rotor.