• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.2
• /
• pp.119-132
• /
• 1990

To design protection coordination for an electric power distribution system, an expert system is developed, using both the veteran expert's heuristics and the guide book for the distribution facility operation considering feeder configuration, service route, load characteristics fault current and load current. The expert system developed in this papaer determines the type of protective device(clearing current and sequence). The location and rating change of protective device in the old feeder is realized by using old database. Current(T-C) curves of various kinds of protective devices are stored in Knowledge Base (KB). The expert system is developed on a 32 bit personal computer using PROLOG, AutoCAD,dBASEIIIPLUS and FORTRAN. To compute the fault current and loadflow, FORTRAN is used.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.2
• /
• pp.132-139
• /
• 2001

In this research, we have developed a load/unload device capable of correcting the position automatically. Characteristic technologies such as compensation, control, guidance and communication have been modified and implemented on an existing electromagnetic guided AGV, helping to realize open system and distributed cooperation. We have applied the developed AGV with remote control and heterogeneous load/unload mechanisms in a machining system composed of various equipment such as machining centers, CMN and AS/RS and found that the AGV provided position error within $\pm$2mm.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.189-192
• /
• 2011

In solid rockets, a pintle thruster is a modulatable thrust device which controlls nozzle throat area. In this study, effect of bore on aerodynamic loads in a SNECMA modulatable thruster was carried out. Existence of bore resulted in reduced aerodynamic load.

• Journal of Environmental Science International
• /
• v.23 no.2
• /
• pp.323-330
• /
• 2014

Transport of bed load and suspended particle in coastal waters is main factor causing change in shoreline, and effective measurement method and appropriate equipment is required. To measure bed load and suspended particle transport an equipment was designed and manufactured, and it was applied in the field. The equipment consists of four main elements, body supporter, bed load and suspended particle sampler, sampler support and lock. Eight samplers were installed along the circumference of each supporter, and each sample is a 45-degree intervals. The field experiment was done once along Gyeongpo beach in August 2013. This note described the design and function of the equipment and results of field experiments.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.7 no.2
• /
• pp.171-183
• /
• 1995

Generally, among many kinds of shading devices such as venetian blind, sunscreen, louver and curtain, venetian blind is using widely because the mechanism is so simple and easy to use solar insolation by controlling the slat angle. Analysis of time dependent heat transfer through the window with venetian blind is very important in order to use it effectivly. Therefore, in this study, theoretical thermal analysis method was developed to analyze time dependent heat transfer through a double pane window with and without venetian blind, and was made one module of TRNSYS(A Transient Simulation Program)program. By this way, it was analyzed that how much the variation of slat angle, slat colour and slat absorptivity of venetian blind would be affected on the heating and cooling load of building, and also which colour and angle of slat was optimal for the heating and cooling load of building.

• Proceedings of the KIPE Conference
• /
• 1996.06a
• /
• pp.71-75
• /
• 1996

As the Three-level ZVS PWM DC-DC converter operates likewise full-bridge ZVS PWM DC-DC converter and the blocking voltage of each switching device is a half of the DC-link voltage, it is suitable for the high imput voltage applications. However, it has some problems as follows; The blocking voltage of each devices is unbalanced and it causes the power losses of the inner switching devices to be increased. Also, it has narrow load range so that the switching losses and the efficiency are reduced as it goes to the light load. This paper presents an nove Three-level ZVS PWM DC-DC converter, which can reduce the overvoltage of the outer switches, eliminate the unbalance of the voltage sharing between the switches at turn-off due to the stray inductances, and operate from no load to full load. The characteristics and the performances of the proposed Three-level ZVS PWM DC-DC converter are verified by simulation and experimental results

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1913-1917
• /
• 2000

SMD Equipment convey an electronic parts at high speed, then assemble parts into a circuit board, and it develop a long time-duration dynamic force to be caused by moving mass. Vibration problem to be caused by SMD Equipment have an effect on micro-meter level's precision production process, directly, and dynamic stability of building. In the cause of quantitatively access about its vibration problem, input information(or data) of structure dynamic analysis need accuracy information of dynamic load. Determination of Dynamic load is various kinds of method using experimental and theory. In this paper, we got dynamic load using direct measurement method. We expect that an study on the dynamic load characteristic of SMD can be used to Equipment development of low level vibration and basis information of structure dynamic analysis.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.12
• /
• pp.601-608
• /
• 2001

The ever increasing density of adjustable speed drives(ASD) device with non-linear operating characteristics has been to put tremendous harmonic stress on end user's electrical application. All ASD controllers which employ solid state power devices cause harmonic currents in the source side line. This paper describes harmonic problems for use of ASD. In order to investigate the effect of harmonics caused by using of nonlinear load at the low voltage system, we fixed up simple load model and measured the voltage and current waveforms. Measurement results show that additional operation of linear load at the parallel bus with nonlinear load such as ASD is helpful to the reduction of harmonic influence.

• Journal of the Korean Solar Energy Society
• /
• v.28 no.6
• /
• pp.33-39
• /
• 2008

The purpose of this study is not only to evaluate the stress behavior of tubes in superheater in HRSG during the load change operation but also to find root causes of failure from stress behavior. Firstly, temperature during operation was collected to perform stress analysis from actual HRSG. Part load and full load stress analysis which can be represented as the whole load change operations were performed using commercial finite element software. The possibility that can lead to tubes failure is found by stress analysis and its results is compared with metallurgical mircrostructure of failed tube which was taken from actual HRSG.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.86-88
• /
• 2007

In solar power system, the height and azimuth of the sun are important parameters which control generated power magnitude. The tracking method that controls the daily generation magnitude according to latitude and longitude using the two axles is often used in the existing sunlight tracking system today. In this two-axle PV track control system, the self-load is concentrated on one FRAME. It is influenced of the regular load, snow load and the wind load, etc. It is difficult to set up the system in the conventional building. This research is a development about the small-scale economy track device of independent load-dispersing solar generation system. The position tracking algorithm is through the new coordinates transformation calculating the height and azimuth of the sun.