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.

광산 축전차용 방폭형 축전지 연구 A Study on Explosion-Proof Storage Batteries for Mine Storage Tanks

Byeong-Chul Yu

There is no research or alternative technology to use low-efficiency, high-cost lead acid batteries, which are used as a power source for storage tanks for transporting coal in mines, into high-efficiency, eco-friendly lithium batteries, so they can be replaced with lithium-ion batteries to improve the working environment. It not only ensures the safety of workers and increases the operating efficiency of storage batteries by extending the life of the battery, but also reduces cost losses caused by arranging separate locations and personnel due to hydrogen gas generated when charging and discharging lead acid batteries. In order to achieve this, we developed an explosion-proof lithium battery that can ensure safety by applying explosionproof technology that can respond to methane gas explosion environments, high temperature, dust, and high humidity situations of more than 90% relative humidity, which are essential in coal mines.

종방향 장력 및 외부 굴절률에 둔감한 이중 테이퍼된 이중 클래딩 광섬유를 활용한 온도 측정에 관한 연구 Study on Temperature Measurement Using Dual-Tapered Double-Clad Fiber Insensitive to Longitudinal Strain and External Refractive Index

Minchan Bae ; Jaeho Seo ; Yong Wook Lee

In this study, we have demonstrated temperature measurement using dual-tapered double-clad fiber (DT-DCF), which generates in-fiber Mach-Zehnder interference and is insensitive to longitudinal strain and external refractive index (RI) perturbations. In the transmission spectrum of the fabricated DT-DCF, two interference dips were selected as sensor indicators and designated D1 and D2. The spectral responses of the two sensor indicators were investigated for ambient temperature, longitudinal strain, and surrounding refractive index variations. First, the ambient temperature of the DT-DCF was increased from 30 to 80°C using a hot plate to investigate the wavelength shifts of D1 and D2 with temperature changes. D1 and D2 showed temperature-induced wavelength shifts of ∼3.98 and ∼3.80nm, and the adjusted R 2 values in linear regression results were evaluated as ∼0.99746 and ∼0.99863, respectively. For longitudinal strain variations from 0 to ∼4137.94με, applied to the DT-DCF, D1 and D2 showed strain-induced wavelength changes of -0.48 and 0.08nm, respectively. From this strain response of the DT-DCF, it is expected that an unwanted longitudinal strain of 100με, which can be applied to the DT-DCF during temperature measurement, can cause measurement errors of 0.30% and 0.06% for D1 and D2, respectively, over the entire temperature measurement range (30∼50°C), confirming that the DT-DCF is insensitive to longitudinal strain. Similarly, for the surrounding RI changes of the DT-DCF (from 1.3330 to 1.4201 RIU), D1 and D2 showed RI-induced wavelength shifts of -0.16 and 0.08nm, respectively. From the RI response of the DT-DCF, we can see that the above total RI change can introduce measurement errors of 0.46% and 0.24% for D1 and D2, respectively, during temperature measurement, and that the sensor indicators are insensitive to external RI.

스마트 피팅 로봇 시스템 개발에 관한 연구 A Study on the Development of Smart Fitting Robot System

Eun-Young Kim ; Kyoung-Hwa Jung ; Gye-Ho Hwang

In our lives, manikins are manufactured to fit the user’s standards and body type and are produced and distributed in standardized sizes and used in clothing stores. In general, the clothing we use is displayed on a manikin made to fit a specific body type, the user selects the clothing, tries it on, and selects and purchases the clothing. From the user’s perspective, the user has to have a process of trying on the clothing because the clothing size and the user’s body size are different, and the user is subject to time and space constraints.

SDBD 발생 시 메시 접지 전극을 이용한 이온 풍속의 향상 Enhancement of Ionic Wind Using a Mesh Ground Electrode During SD

Jun Yoon ; Ung-Hui Yun ; Jin-Gyu Kim

Recently, active flow control technology has become a rapidly developing topic in aeronautics. Active flow control can be used to improve airfoil durability, reduce noise, and improve fuel efficiency. A typical device for active flow control is a plasma actuator using SDBD(Surface dielectric barrier dischage). Plasma actuator using SDBD has the following advantages. Plasma actuator using SDBD doesn’t require mechanical devices, have low power consumption, and are fast responsive. However, this device is only applicable to small aircraft due to the relatively low ionic wind velocity. Therefore, in this study, the shape of the ground electrode is changed to a mesh instead of a plane plate to increase the ionic wind velocity. The ionic wind velocity is up to 1.33 times higher with the mesh ground electrode than with the typical plane ground electrode used as a plasma actuator under the same condition (20kV, 60Hz). Also Power consumption of device is greater with the mesh ground electrode. 1 mm grid mesh electrode induces the strongest ion wind relative to power consumption. The results of this study will provide useful data for research on active flow control devices using SDBD.

Tie Switch 구성의 PV 연계형 저압직류배전계통의 보호 시스템 구성 Configuration of Protection System for Low Voltage DC Distribution System with Photovoltaic System including Tie Switch

Hun-Chul Seo ; Keon-Woo Park ; GI-Hyeon Gwon

DC power distribution is attracting attention due to the increase in renewable energy and DC load. Due to the characteristics of the DC distribution system configuration such as DC/DC converters, the new protection system are essential for stable operation of the low voltage DC (LVDC) distribution system. This paper proposes a new protection method in the LVDC distribution system with photovoltaic (PV) system connected by tie switch. In the system configuration of the proposed method, circuit breaker(CB)s are installed at both ends of the line. The proposed protection system includes both the fault detection and the recovery procedure.

전원 분배망에서 안정적인 전원 공급을 위한 디커플링 커패시터의 선정 방법 Selection Method of Decoupling Capacitor to Maintain Stable Power Supply in a Power Distribution Network

Hyeon-Woo Jeong ; Kyo-Beum Lee

This paper analyzes a technique for selecting decoupling capacitors to maintain a stable power supply in a power distribution network. It analyzes the effect of decoupling capacitors in the frequency domain of the power distribution network and calculates the target impedance for placing the capacitors. To solve the problem of the original decoupling capacitor placement, the capacitor value was selected using the equivalent series resistance of the capacitor. The effectiveness of the proposed method when selecting decoupling capacitors in a power distribution network is verified through simulation.

물류자동화설비 전용 변압기 수용률에 대한 국내자료의 신뢰성 분석 Reliability Analysis of Domestic-Data on the Demand Factor of Transformers Dedicated to Logistics Automation Facilities

Byung-Hyeok Seo ; Rae-Young Kim

The domestic logistics market is pursuing logistics automation and logistics smartization to meet consumer demands. Logistics automation has the advantage of reducing logistics costs and increasing delivery speed.

증강형 GaN FET 모델링 및 회로 구현에 대한 연구 Study on E-mode GaN FET Modeling and Circuit Implementation

You-Jin Shin ; Ho-Young Cha ; Hyun-Seop Kim

This study presents the modeling and implementation of GaN logic circuits using the MIT Virtual Source GaNFET (MVSG) model for E-mode p-GaN/AlGaN/GaN HFETs. Parameters for E-mode HFET and 2DEG characteristics were determined using the MVSG model, optimized to establish stable logic circuits. Subsequently, GaN logic circuits were fabricated through monolithic integration, demonstrating their stability and potential for driver IC design. The fabricated inverter circuit demonstrated an outstanding noise margin and operated successfully at 500kHz.

차량 시스템의 전원 차단 시간을 이용한 전류 적산법의 SOC 추정오차 보정 Compensation of SOC Estimation Error in Current Integration Method Using Power-Off Time of Vehicle System

Dong-Min Bae ; Kyo-Beum Lee

This paper proposes a method of compensation for the SOC estimation error of the current integration method using the power-off time of the vehicle system. The current integration method can derive accurate results in real time with simple algorithm application and low cost. However, a challenge arises when errors in the battery’s initial values and noise from current measurements accumulate, increasing SOC estimation errors. To solve this problem, the time from the vehicle’s ignition off to ignition on is regarded as the battery rest time. After a specific rest time, the accumulated error is corrected by measuring the open voltage of the battery and correcting the SOC value of the existing current integration method. To verify the proposed method a Battery Monitoring System (BMS) that can measure the amount of current change in real time is configured and the accuracy of the estimation method is verified by performing battery charging and discharging experiments.

전력 라우터를 이용한 마이크로그리드간의 전력 전달 및 거래에 관한 연구 A Study on the Transfer and Transaction of Power between the Interconnected Microgrids Using Power Router

Kwang-Myoung Son

This paper deals with power transaction between the interconnected microgrids by binding them using power routers. The power router is a device that transfers electric power between its interfaces in any form and direction using power electronics technology. Electric power router plays a key role in the network of microgrids for its versatility and flexibility of the power transfer. The conventional approaches assume that there is a market computer that handles the transactions of all the power routers that are participating in trading power. This paper proposes a method of power transaction between routers without market computer using distributed approach. This paper presents a method of finding the optimal routes from the power source to the consumer and spreading the transaction information between the microgrids by relaying routing packets. The proposed method is efficient and robust for power transaction between microgrids compared with the conventional method.

NFPA 미국방식과 국내 발전기용량 계산 산정방법 비교 분석 연구 A Comparative Analysis Study about NFPA of US and Generator Capacity Calculation Methods of Korea

Jong-Sun Han ; Rae-Young Kim

In this study, the methods for calculating generator capacity currently applied in Korea and the United States were reviewed, and the differences in the calculation methods were examined. Furthermore, two completed buildings were selected for actual verification through calculation and comparative review. The results showed that there was no significant difference in the methods for calculating generator capacity, but the capacity was calculated to be 10-20% larger depending on the characteristics of the building and the type of load. It was found that the NFPA standards apply more specific and detailed baseline data and various constants (such as the method of applying the full-load current for different motor capacities during startup / operation, startup factor, etc.). However, the KDS 31 60 20 method offers a wide range of choices in selecting baseline data (voltage drop of the generator, startup factor by type of startup, harmonic content rate, etc.), resulting in different applications by designers even for the same motor capacity. This area requires focused improvement and legal revision in the future, along with the need to provide specific values for load characteristics and various factors.