• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.151-152
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• 2011

본 논문에서는 스마트 그리드에 적용되는 2MVA 배터리 에너지 저장 시스템(BESS, Battery Energy Storage System)의 제어 알고리즘을 제안하고 검증하였다. BESS는 전력변환을 위한 PCS(Power Conditioning System), 배터리 제어 및 상태확인을 위한 BCS(Battery Conditioning System)와 상위 시스템으로부터 지령을 받아 PCS와 BCS를 제어하는 PMS(Power Management System)로 구성되어 있다. BESS는 풍력안정화를 위해 EMS(Energy Management System)의 지령을 받아 운전모드를 선택하고, 운전모드에 따라서 계통측 전력을 제어하거나 배터리측 전류를 제어하고, 배터리의 완전충전을 위해 전압제어를 한다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.17-20
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• 2008

HYOSUNG manufactured and tested 1kW class PEFC systems to generate electrical and thermal energy for each residential usage. In particular, HYOSUNG developed power conditioning system that performs over 91% electrical conversion ratio specified in 1kW class PEFC systems. Prior to system integration, we tested each performances of components to derive control issues from it. In addition, we have been developing the adequate simulator to describe and predict system performance. In this paper, we verified HYOSUNG's 1kW class PEFC systems are valid for residential energy sources by testing the characteristics of systems and performances of main components.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.508-509
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• 2011

신재생 에너지원인 풍력과 태양광등 대체에너지의 확대보급과 풍력발전과 에너지 저장장치와 같은 신재생 에너지원 및 스마트그리드 분야에 적용을 위한 대용량 PCS(Power Conditioning System) 개발에 대해 설명한다. 실외 설치환경 및 장소에 따른 많은 제작, 운영조건에서 벗어 나고자 냉각방식을 수냉형으로 설계하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1570-1575
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• 2018

The increased penetration of PV is impacting on grid operation and in particular the voltage within the local grid can be significantly influenced by the various PV systems. The increased penetration of PV is impacting on grid operation and in particular the voltage within the local grid can be significantly influenced by the various PV systems. This paper describes domestic technical standard of Photovoltaic(PV) PCS(Power Conditioning Systems)- Characteristics of the utility interface. Especially protective function test items of 1) Output overvoltage protection test, 2) Output undervoltage protection test, 3) Frequency rise protection test, 4) Frequency fall protection test, 5) System voltage's momentary interruptions, 6) System voltage distortion capability test. Therefore in this paper protective function test item of facilities evaluation detailed standards for new renewable energy, small, medium and large photovoltaic inverter standard is studied and analyzed and finally full tested by PV inverter performance function.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.579-587
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• 2001

This study investigates particle collection characteristics of a cylindrical electrostatic precipitator. Experimental work has been made for the submicron particles. The effects of polarity of discharge electrode wire, particle diameter, gas velocity, gas temperature, and specific corona power on the particle collection efficiency are investigated. The efficiency of negative corona is higher than that of positive corona. as the particle diameter increases, the efficiency is decreased when the diameter is in the range of 0.02-0.6 micron, but is increased for the nanometer particles with diameter smaller than 0.02 micron. The efficiency is increased with increase of specific corona power. As the gas temperature increases, overall collection efficiency is increased for a negative corona, but is deceased for a positive corona.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.653-665
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• 2001

The characteristics of the pulsating flow in a hydraulic pipe have been investigated. It is necessary to study the power control of the power transmission system in the landing gear system of aircraft and the design of robots. In this system, the power transmission pipeline is composed of a hydraulic system, and the operating flow is unsteady flow. The wave equation varying with frequency is analyzed in order to investigate the characteristics of unsteady flow in such a pipe. This wave equation involves the propagation coefficient in terns of frequency and viscosity. The theoretical result of this wave equation are compared with experimental result. Each wave equation, varying with the propagation coefficient, is analyzed theoretically. then, a sinusoidal wave generator is built in order to make better sinusoidal waves, and a rectifier is built to eliminate the noise from the hydraulic pump. The theoretical results of the wave equation in the flow of viscous fluid agree well with experimental results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.265-277
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• 1993

Recently, underground transmission system is growing continuously according to the electric power demand increase in the downtown area. Even if domestic cable makers are manufacturing 154kV oil filled cable and joint, the design technology of cable-joint has not been fully self-reliance. This study is aimed at the detail heat transfer analysis of 154kV cable-joint. So, that is cut into the five sections in order to analyze a conjugate natural convection in two dimensional $r-{\theta}$ coordinate. The streamline and temperature distributions are obtained for each sections. Also the changes of those are analyzed with respect to the variation of transmission currents and cable-joint surface heat transfer coefficients. The same analyses are also shown in view point of the maximum temperature of conductor and local equivalent conductivity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.4
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• pp.299-305
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• 1992

Saltation occurs in horizontal flow of solid and gas when the carrier gas velocity is small enough to permit enough to settling of the solid particles within the transport line. So we should examine the pneumatic flow system to lessen the unbured carbon in the power plant. In this paper the saltation velocity was studied on the various solid flow rate in the constant pipe diameter and on the various temperatures of the flow gas. The air velocity in the power plant transport lines was also surveyed in order to compare with the saltation velocity. As the solid flow rate increased in the constant diameter, saltation velocity increased and as the temperater of the flow gas inereased in the transport line, saltation velocity also increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.4
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• pp.333-338
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• 2007

The object of this study is to find the optimal insulation design conditions of a HTS power cable cryostat. The optimum condition of a cable cryostat is obtained by varying types of MLIs, cable core weights, spacer diameters, winding pitches and MLI layer numbers. As the weight of cable core is increased, conduction heat transfer from surroundings to cable cryostat is increased. But as the spacer pitch is increased from 120 mm to 200 mm, the heat leak of cable cryostat remains almost constant. The optimal number of MLI layers is suggested. Double ply MLI is more effective than triple ply MLI and the insulation effect is best when the number of MLI layers is 36.

• Journal of Power System Engineering
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• v.18 no.1
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• pp.14-21
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• 2014

Piezoelectric fans are thin elastic beams whose vibratory motion is actuated by means of a piezoelectric material bonded to the beam. These fans have found use as a means to enhance convective heat transfer while requiring only small amounts of power. This study presents new types of models with heat sink having air passage and investigates experimentally their heat transfer characteristics. From the comparison results for four models, the heat transfer coefficients of model 1 are approximately 44~66% higher than those of the reference model 0. The model 1 show the best overall performance about heat transfer and cooling capability. As shown in above results, it is necessary to design the heat sink with air pass for cooling of electronic devices, in order to increase the convective heat transfer coefficient of a piezoelectric fan for electronic cooling.