• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.423-424
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• 2017

본 논문은 에너지저장(ESS : Energy Storage System) 기능을 갖는 1,200kVA급 모듈형 하이브리드 무정전전원장치(UPS : Uninterruptible Power Supply)에 관한 것이다. 제안한 모듈형 하이브리드 UPS는 평상시에는 무정전전원장치의 기능을 수행하면서 잉여 전력을 미리 배터리에 저장하였다가 첨두부하시 또는 전력 부족시 에너지저장 기능을 하여 전력을 조절할 수 있다.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3159-3161
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• 1999

This paper aims at developing remote control system to control and monitor distributed various devices through internet or information communication network. SNMP (Simple Network Management Protocol) and UPS (Uninterruptible Power Supply) are adopted for network management protocol and applied device, respectively. For controlling and monitoring distributed devices in real-time, Java-environment software is constructed. Also, general-use interface controller between network device and applied device is proposed. Finally, serial communication such as RS-232 and RS-485 is used between controller and applied device.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2259-2261
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• 2003

본 연구에서는 전원선로의 정전시나 입력 전원에 이상 상태가 발생했을 때 정상적인 전원을 컴퓨터에 공급하는 Power Supply 내장용 무정전 전원장치(Uninterruptible Power System : UPS)의 개발하였다. 본 연구에서 개발한 내장형 무정전 전원장치는 마이컴(PIC16C74A)을 이용하여 컴퓨터 Power Supply 내부에 장착하였으며, 사용자가 편리하도록 하기 위해서 내장형 무정전 전원장치의 그래픽 사용자 인터페이스를 구현하였다.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.158-162
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• 2002

The parallel operation system of multiple UPS(Uninterruptible Power Supply) is used to increase power capacity of the system or to secure higher reliability at critical loads. In the parallel operation of the two UPSs, the load sharing control to maintain the current balance between them is a matter of consequence. In this paper, a highly precise load sharing controller is proposed and implemented for the parallel operation system of two UPSs. After that, a good performance of the proposed method is verified by simulation in the parallel operation system with two UPSs.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.715-716
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• 2007

배전선로의 주상변압기 교체 공법은 시공방법에 따라 전력품질이 좌우된다고 할 수 있으나, 지금도 개선되지 않은 방법으로 작업을 하고 있어 부실시공에 의한 고장정전과 안전사고가 근절되지 않고 있으며, 공사비가 과다발생 하는 문제점이 있는 등 전력신기술에 의한 시공품질 관리가 절실히 요구되는 분야이다. 따라서, 본 논문에서는 새로운 위상변환장치를 이용한 무정전 공법을 제안한다. 제안한 공법은 현행 공법의 문제점을 획기적으로 개선함으로써 안정적인 전력공급과 동시에 배전원가 절감에 따른 저렴한 전기요금으로 국민생활에 편리함을 더하고 국가경제 발전에 기여하게 될 것으로 기대된다.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.812-819
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• 2014

The proposed technical work attempts to compare the two key technologies of power distribution, i.e. direct current (DC) and alternating current (AC) in a fiscal manner. The DC versus AC debate has been around since the earliest days of electric power. Here, at least four types of a low voltage DC (LVDC) distribution are examined as an alternative to the existing medium voltage AC (MVAC) distribution with an economic assessment technique for a project investment. Besides, the sensitivity analysis will be incorporated in the overall economic analysis model to cover uncertainties of the input data. A detailed feasibility study indicates that many of the common benefits claimed for an LVDC distribution will continue to grow more profoundly as it is foreseen to arise with the increased integration of renewable energy sources and the proliferation of energy storage associated with the enhanced utilization of uninterruptible power supply (UPS) systems.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.704-711
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• 2013

Data center is an information hub and resource for information-centric society. Since data center houses hundreds to ten thousands servers, networking and communication equipment, and supporting systems energy saving is one of the hottest issues for green data center. Among several solutions for green data center this paper introduces higher voltage direct current (DC) power feeding system. Contrary to legacy alternating current (AC) power feeding system equipped with Uninterruptible Power Supply (UPS), higher voltage DC power feeding system is reported to be a more energy efficient and reliable solution for green data center thanks to less AC/DC and DC/AC conversions. Main focus of this paper is on reliability issue for reliable and continuous operation of higher voltage DC power feeding system. We present different types of configuration of the power feeding systems according to the level of reliability. We analyze the reliability of the power feeding systems based on M/M/1/N+1/N+1 queueing model. Operation of the power feeding system in case of failure is also presented.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.6 no.6
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• pp.49-57
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• 1992

This paper proposes a Intel 8097 single-chip microprocessor based instantaneous voltage control scheme of inverter for UPS(Uninterruptible Power Supply). There microprocessors are used to control the output voltage and frequency of the inverter, the synchronization with by-pass, and the switching of the static switch. And the status and operating conditions of UPS systems is monitored by micro processor. The inverter output voltage is controlled instantaneously with a double regulation loop so that it has very good dynamic response for the varying loads or nonlinear loads as a rectifier. And also, the software and hardware of control system is described. From simulation and experimental results, it is shown that the proposed scheme has very good performance.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.462-465
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• 2009

This study described the design and construction of uninterruptible power supply(UPS) system for supercomputering system. KISTI's supercomputer system is served for all 24 hours, and power be achieved in stable voltage and frequency range. We analyzed the electric power usage for 4 years, and we considered cost and stability and we contructed UPS for supercomputer system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.321-323
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• 2009

When power failure occurs at multi-housing complex, auxiliary generator or emergency generator starts to provide power to households. This power is connected to emergency power ELB(Earth Leakage Breaker) at home distribution panel board and supplies power only for emergency light in living room but for heating system, refrigerator and other inevitable apparatuses that are in need of uninterruptible power. Since those domestic appliance are fed from common power line, they are inoperable during power failure. Our research is to resolve this problem by developing compatible relay-drive common/emergency-power ATS (automatic transfer switch) for home distribution panel board. In case of power failure, it transfers automatically and commences to provide power from emergency generator. Through this, Consumers can reach satisfaction where common power loads operate without any problem under both ordinary and power failure condition.