• 조명전기설비학회논문지
• /
• 제25권8호
• /
• pp.132-139
• /
• 2011

Technical requirements for medium voltage class circuit breaker were harmonized by IEC and IEEE, and IEC newly adopted the requirements for class S2 circuit-breaker for overhead-line with the ratings of high-frequency TRV(Transient Recovery Voltage), which IEEE already adopted. Under these circumstances, KERI(Korea Electrotechnology Research Institute) studied testing technologies and facilities, which enable to perform interrupting capacity tests for class S2 circuit-breaker. As results, KERI could carry out interrupting capacity tests for medium voltage class circuit breaker rated up to 3-phase 52[kV] 40[kA], which satisfies the IEC standard.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 1999년도 추계종합학술대회
• /
• pp.486-489
• /
• 1999

This paper deals with the design rule and performance results of the transient voltage blocking devices (TBD) for low-voltage mains on shipboard. The proposed TBD consists of metal oxide varistors (MOV) and L-C filter to improve noise-elimination performance. Three kinds of TBDs are fabricated and tested by using a combination surge generator which can produce the standard impulse current of 8/20${\mu}$s 2.1kA. As a reults, the proposed TBD with series L-C filter has more excellent transient blocking and noise reduction performance than the conventional TBDs.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
• /
• pp.553-555
• /
• 1987

In the standard system of low voltage-oriented ZnO varistor,a small amount of $Sb_2O_3$ was added to improve the nonlinear exponent and then to find the variation of breakdown characteristics, 0.1m/o-SiO and 0.1m/o-$TiO_2$, respectively,were added We considered relationship between the breakdown voltage of systems and the microstructure. We found that the system containing 0.1m/o-$Sb_2O_3$ showed very high nonlinear exponent. And we found that SiO enhanced breakdown voltage and $TiO_2$ lowered it.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2017년도 전력전자학술대회
• /
• pp.70-71
• /
• 2017

This paper presents a new cascaded boost multilevel converter topology for distributed generation (DG) systems. Most of DG systems, such as photovoltaic (PV), wind turbine and fuel cells, normally require the complex structure power converters, which makes the system expensive, complex and hard to control. However, the proposed converter topology can generate a much higher output voltage just by using the standard low-voltage switch devices and low voltage DC-sources in a simplified structure, also enhancing the reliability of the switch devices. Simulation and experimental results with a 1.2kW system are presented to validate the proposed topology and control method.

• Transactions on Electrical and Electronic Materials
• /
• 제17권1호
• /
• pp.21-24
• /
• 2016

A junction box used in a 3 kW photovoltaic power generation system plays a role in collecting and supplying the direct current voltage produced by photovoltaic modules to an inverter. It is also used for facilitating maintenance checks and protecting the module and inverter by keeping the voltage constant. As for the junction box, using it in a parallel connection creates a difference between the setup modules. In order to compensate, an inverse voltage diode is used. But the high-power created through the solar generator can be delivered to the inverter through the inverter regularly. Therefore, a component can break down due to excess heat. And consequently short circuits and electric leakage occurs. In this study, using a junction box that enabled the bypass of high electric power, it was possible to reduce heat generation by approximately 35℃ when compared to a standard junction box.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.291-295
• /
• 2005

This paper presents the modeling of grounding system on Korean electric railway system. The system model is composed of the catenary system, the grounding-system, the sub-sectioning post, the fault point, the sectioning post, the autotransformer in the substation, and the electric vehicle. The increment of rail-ground voltage may be thought as an amplifier of danger on human body of equipment insulation. The rail-ground voltage on steady state and on fault condition should be under standard limit voltage. To analyze grounding system for steady state and fault condition on Korean railway, modeling for each railway system is performed by 10-port network model. Modeling and analysis of present grounding-system are important to protect human and electronic equipments. The examinations for systematic grounding-system are investigated.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
• /
• pp.1068-1070
• /
• 2005

This study sorted high voltage motors by the voltage and the capacity and analyzed the property of motor-start. So we found out some problems of the starting circuit from several sites, and made the answers of the problems. If these results of our study are utilized in new WTPs, the safety of the starting circuit will be improved and the life of electric power system will be longer. We recommend this study as a reference when our company founds the standard of electric facility design.

• 센서학회지
• /
• 제28권2호
• /
• pp.121-126
• /
• 2019

The voltage-controlled oscillator is one of the fundamental building blocks that determine the signal quality and power consumption in RF transceivers for wireless sensor networks. Ring oscillators are attractive owing to their small form factor and multi-phase capability despite the relatively poor phase noise performance in comparison with LC oscillators. The phase noise of a ring oscillator can be improved by using a coupled structure that works at a lower frequency. This paper introduces a 2.4 GHz low-noise ring oscillator that consists of two 3-stage coupled ring oscillators. Each sub-oscillator operates at 800 MHz, and the multi-phase signals are combined to generate a 2.4 GHz quadrature output. The voltage-controlled ring oscillator designed in a 65-nm standard CMOS technology has a tuning range of 800 MHz and exhibits the phase noise of -104 dBc/Hz at 1 MHz offset. The power consumption is 13.3 mW from a 1.2 V supply voltage.

• 전기전자학회논문지
• /
• 제26권2호
• /
• pp.196-204
• /
• 2022

Electrostatic discharge (ESD) protection devices of P-type embedded silicon-controlled rectifier (PESCR) structure were analyzed for high-voltage operating input/output (I/O) applications. Conventional PESCR standard device exhibits typical SCR characteristics with very low-snapback holding voltages, resulting in latch-up problems during normal operation. However, the modified device with the counter pocket source (CPS) surrounding N⁺ source region and partially formed P-well (PPW) structures proposed in this study could improve latch-up immunity by indicating high on-resistance and snapback holding voltage.

• 전기전자학회논문지
• /
• 제20권2호
• /
• pp.192-195
• /
• 2016

본 논문에서는 저항과 BJT를 사용하지 않고 sub-threshold 영역에서 동작하는 저전압, 저전력 기준전압 발생기를 설계하였다. CTAT 전압 발생기는 두 개의 NMOS 트랜지스터를 이용하여 구성하였고, 충분한 영역의 CTAT 전압을 발생시키기 위해 바디 바이어스 회로를 이용하였다. PTAT 전압 발생기는 PTAT 전압을 생성하기 위해 MOS 트랜지스터 입력 쌍의 서로 다른 사이즈 비를 이용하는 차동증폭기 형태로 구성하였다. 제안한 회로는 $0.18-{\mu}m$ 표준 CMOS 공정으로 설계되었다. 시뮬레이션 결과로 290mV의 출력 기준 전압을 가지며, -$20^{\circ}C$ 에서 $120^{\circ}C$의 온도 변화에서 92 ppm/$^{\circ}C$의 전압 변화 지수와 전원전압 0.63V에서 15.7nW의 소모 전력을 갖는 것을 확인하였다.