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.

스마트폰 충전용 솔라패드를 이용한 사이니지용 2×2 LED Tag ID 신호 수신 에러를 정정하는 방법에 관한 연구 A Study on Error Correction of Signage 2×2 LED Tag ID signals to Charging Solar Pad on Smart Phone

http://doi.org/10.5207/JIEIE.2020.34.12.001

Jong-Yong Park ; Deok-Gun Woo ; Jae-Sang Cha

Digital signage has been widely spread for advertising and requires more interactions with customers. The adopted communication methods are limited by low-speed, low-capacity and also RF based communication system is vulnerable to security. Visible light communication can provide high-speed and large-capacity communication and improved security. By using a solar pad as a receiver, it solves the inconvenience that the photodiode must be positioned in line with visible light. This paper proposes a visual light communication system between a 2×2 LED Tag on a digital signage and a portable solar pad on a smart phone Depending on smart phone holding pattern, a shadow occurs by a finger and it causes communication errors. To solve this problem, I propose to use three channels as to transmit data and use one channel to transmits parity bits. This approach is verified to recover errors from fingers or palm on the solar pad. This allows signage to provide a more improved user experience to users through visible light communication.

다중권선 ZCT를 이용한 누전차단기의 누전 검출회로 자동진단 연구 A Study on Automatic Diagnosis of Residual Circuits of RCD Using Multiple Winding ZCT

http://doi.org/10.5207/JIEIE.2020.34.12.009

Deog-Gyeong Yoon ; Sang-Han Park ; Ki-Ho Jang ; Gwang-Su Kim ; Moon-Soo Seo

Residual current device(RCD) is a protective device used for the purpose of preventing electric shock accidents, fires caused by short circuits, and damage to equipment caused by arc fault. RCD shall be checked at least once a month using the manual testing. However, if a power shutdown is not possible depending on the load, it is used without periodic check. Therefore, even if the actual leakage current occurs, it will lead to a bigger accident. In this paper, the RCD capable of automatic diagnosis of detecting residual circuits without opened was developed and its performance verified.

염류용액 방전의 구동 특성에 관한 연구 A Study on the Driving Characteristics in Saline Solution Discharge with Pin to Plate Electrodes

http://doi.org/10.5207/JIEIE.2020.34.12.016

Joong Kyun Kim

In this study, the change in the characteristics of the saline solution discharge were investigated with the variation of driving condition. Regardless of the pulse polarity to the pin electrode, the amplitude of circuit current decreased but flew continuously with the insertion of series resistor to the power source when 5% duty ratio pulse was applied to a saline solution of 0.9% mass per unit volume in a pin to plate structure. The temperature of the discharge medium was measured from the spectrum of the hydroxy group molecular lines near 308 [nm] obtained during discharge, and the electron density using the Stark broadening of the Hβ line at 486 [nm], which is one of Balmer series hydrogen atomic line. The maximum temperature and electron density in the discharge medium decresed with the increase of series resistor inserted when the negative pulse was applied to the pin electrode. On the other hand, the positive pulse application to the pin electrode hardly led a temperature change while the change in the electron density was observed. It is estimated that the negative pulse application to a pin electrode and series resistor insertion in the driving circuit will helpful to widening the operation window in a liquid discharge.

소형건축시설물을 위한 IoT기반 원격제어감시 시스템에 관한 연구 A Study on IoT-based Remote Control Monitoring System for Small Building Facilities

http://doi.org/10.5207/JIEIE.2020.34.12.023

Min-Soo Kim ; Jae-Sang Cha

In this paper, as an IoT-based remote control monitoring system for a small construction facility using Raspberry Pi, a general-purpose IoT processor, it is managed by utilizing remote monitoring and control functions at low cost instead of using expensive dedicated devices for automatic control even in small automation workshops. The goal is to build a system that can do it. I/O board was used and the interface was configured by applying the industrial Modbus protocol to enable monitoring and control over the Internet from a remote location. To support users' simple on-site inquiry and remote monitoring and control services, the Java-based HMI package is configured to configure the system to enable monitoring and control using any smart device that supports a web browser. It was confirmed that a small remote monitoring and control system can be configured through a simple configuration of the Raspberry Pi and I/O board.

Lightning Warnings Using the Logical AND (intersection) Combination between Intra-Cloud Discharge, and Electric Field Data

http://doi.org/10.5207/JIEIE.2020.34.12.029

Hae-Sup Shim

The objective of this study is to identify the optimal warning trigger, and clear conditions of a stand-alone lightning warning system (SLWS) to protect the infrastructure of the National Meteorological Satellite Center (NMSC) against cloud-to-ground strikes. In my prior study [1], it was already found that the logical OR (union) combination with intra-cloud discharges (IC) and cloud-to-ground flashes (CG) was better than AND (intersection) option of them to increase in probability of detection (POD), whereas the critical success index (CSI) as the ideal balance between POD and false alarm ratio (FAR) became worse than IC only. To augment the CSI, as another warning condition, the logical AND combination between IC and atmospheric electric field data (EF) has been explored in this study during the last two summers. Upon conclusion of the study, it was found that the combination was the best in CSI than those of my past studies, and other conditions in all the cases [1, 2, 3, 4, 5], while the penalty was that POD became somewhat lower than the IC OR CG, and IC alone. Finally, the total alarm duration (TAD) including lead time (LT), warning time (WT), and dwell time (DT) showed very little difference among the top three CSI and POD conditions.

친환경 전력케이블용 PP의 백화현상에 의한 절연특성 변화에 대한 연구 A Study on the Degradation of Dielectric Characteristics of Polypropylene for an Eco-friendly Power Cable according to White Rust

http://doi.org/10.5207/JIEIE.2020.34.12.037

Bella Eliana ; Dewimaruto Ratri ; Seunghee O ; Younghun Park ; Hyoungku Kang

Cross linked polyethylene (XLPE) has been widely used for power cables as an insulation material due to its excellent dielectric and mechanical characteristics. However, XLPE can not be recycled after the lifetime of power cables because of its thermosetting property. In many countries, power cables have been developed and installed actively since 1970. It means that the lifetime of power cables is reaching over 50 years. It is known that the lifetime of power cables is around 50 years. Therefore, many power cables in a power grid installed in 1970s should be replaced with new power cables in order to improve the reliability of a power system. In this replacement, there are many studies to change thermosetting materials, XLPE into thermoplastic materials, polypropylene (PP) which can be recycled. This paper deals with the analysis on the dielectric degradation characteristics of PP according to white rust. White rust may occur in power cables due to curvature and scratch which could be caused by bending stress and friction. Especially bending stress is inevitable because of narrow installation area and process of installation. The dielectric degradation characteristics of PP are analyzed under AC as well as lightning impulse voltage test. It is found that the dielectric degradation characteristics of PP according to white rust is more degraded at lightning impulse voltage test than AC voltage test.

100MW급 해상풍력발전단지 계통연계점에서의 능동 전압제어 Active Voltage Control at the PCC of 100MW Class Wind Farm

http://doi.org/10.5207/JIEIE.2020.34.12.045

Gi-Hoon Kim ; Do-Heon Lee ; Eel-Hwan Kim

Sudden output fluctuations, one of the characteristics of renewable energy, degrade the reliability of the power system, and may adversely affect power quality. Therefore, this paper analyzes the voltage fluctuation at the PCC(Point of Common Coupling) according to the output fluctuation using the PSCAD/EMTDC program, as a model of a 100MW class offshore wind farm being built on the Hallim coast in Jeju Island. In order to minimize the voltage fluctuation at the PCC, a computer analysis was performed by constructing a STATCOM at the PCC that can actively compensate for reactive power. In the computer analysis, each power line used a π-type circuit and each wind turbine was equalized as a current source to perform normal operation and transient conditions such as dropping out and grid connection of the wind farm complex. Based on the analysis results, the control method and effect of STATCOM were verified to minimize voltage fluctuations at PCC of a large-scale offshore wind farm.