• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.9
• /
• pp.1590-1596
• /
• 2016

In this paper, catenary wires were analyzed aging through the experiment about a new product and a test sample in accordance with temperature changes from long-term use. In case of the contact wire, the maximum load was reduced within 7% and the tensile strength showed a reduced within 6.7% compared with a new reference standard $110mm^2$. 19 Strands of messenger wire have a little more than a standard value, but result data on tensile test were less than the reference value about stranded wire. Also parts among 49 strands of dropper was found to be smaller than the reference value and it appeared greatly increasing intensity as toward the center of the strand.

• Proceedings of the KAIS Fall Conference
• /
• 2006.05a
• /
• pp.302-306
• /
• 2006

In this study, we analyzed the influence of electrical pole by FEM(Finite Element Method) and developed protective system by designing and interpreting protective system for electrical pole when abnormal strength worked on messenger wire. Protective system did not shed messenger wire under wind pressure and discontent load but did assign a part to preventing rupture of electrical pole through automatically shed messenger wire over fixed strength. Structure of protective system analysis by FEM and prove property by measuring tensile strength for practical product.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1998.10a
• /
• pp.173-179
• /
• 1998

The piping system of a power plant suffers not only thermal expansion according to the temperature variation, but also many kinds of load: steady state vibrations due to the equipment operation or fluid flow, and transient vibrations due to the earthquake or explosion, etc. The snubbers are usually installed on the piping system to allow thermal expansion, and to reduce dynamic responses. Most snubbers are kinds of hydraulic and mechanical type, which can be degraded by leakage and abrasion, and required much cost for maintenance and replacement. Recently the wire rope type snubbers are developed and applied to the power plant, and proved as effective to reduce piping system vibration. Wire rope type snubber uses the bending rigidity and energy dissipation properties of ropes. This paper presents the procedure of design, and the method to apply hysteresis curve to the dynamic response analysis. Experiments were also conducted to confirm design results.

• Journal of Power Electronics
• /
• v.3 no.3
• /
• pp.151-158
• /
• 2003

Three-phase four-wire electrical distribution systems are widely employed in manufacturing plants, commercial and residential buildings Due to the nonlinear loads connected to the distribution system, the neutral conductor carries excessive harmonic currents even under balanced loading since the triplen harmonics in phase currents do not cancel each other This may result in wiring failure of the neutral conductor and overloading of the distribution transformer In response to these concerns, a cost-effective neutral current harmonic suppressor system has been proposed. This paper proposes an improved control method for the harmonic suppressor system under unbalanced load conditions The proposed control method compensates for only the harmonic components in the neutral conductor, and the zero-sequence fundamental component due to unbalanced loading is prevented from flowing through the harmonic suppressor system This remedies overloading and power loss of the system The experimental results on a prototype validate the proposed control approach.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.1
• /
• pp.52-58
• /
• 2014

To improve the performance of clutch actuator of clutch-by-wire system for commercial vehicles, it is necessary to understand the driving characteristics of the system. To explain and predict the effects of driving characteristics on clutch characteristics, AMESim software is used. The simulation model of clutch-by-wire system is developed in the AMESim environments under the geometrical dimensions and driving mechanisms of the clutch-by-wire system, such as the rotation speed of the DC motor, the gear ratio of the reducer, the design parameters of the release fork, the coefficient of the clutch diaphragm spring, and so on. The results show that the theoretical analysis of the clutch-by-wire system for commercial vehicles using the AMESim software find out the driving characteristics of the clutch actuator, and predict the performance characteristics of the clutch-by-wire system.

• Proceedings of the KSR Conference
• /
• 2001.10a
• /
• pp.139.1-146
• /
• 2001

Contact lines are necessary to supply electric locomotives with electric power. As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary wires made by metallic materials are generally used in the open air. They are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the railway locations. In urban area, acid rain may cause a degradation of catenary wire system. Corrosion of catenary wires can make their actual lifetime shorter than that originally designed. Thus, the messenger wires, a kind of catenary wire system, were investigated with respect to corrosion, which include new and the used one collected at the field. They are also vibrated with some amplitude everytime the train passes through the railway. The frequent cyclic load on the wire any result in a fatigue damage, Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 40 to 50% shorter than that of new one in average.

• Journal of the Korea Computer Industry Society
• /
• v.5 no.9
• /
• pp.1095-1100
• /
• 2004

The computer system is gradually complicated because of explosive growth of computer system and IT technology. For efficient management of complicated system, system load monitoring technology is essential. In this paper, we is implemented the real-time load monitoring system based mobile than the traditional methods that are used load-related commands in system manager or specific load application programs based connected wire. Advantage of implemented load monitoring system in this paper is freely saw load information in time and space though mobile method like as PDA, cellular phone, more than traditional methods intime and space.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.43-47
• /
• 2004

Most of LV customer has been composed the 3-phase four wire system distribution system which is supplying simultaneously at the 1-phase & 3-phase load. In this system, the composition of the power apparatus system is simple rather than conventional separation mode of the 1-phase & 3-phase, But due to uneven load unbalance or unclean power quality, various kinds such as do-rating or power losses become an issue. In this paper, we measured and analyzed voltage and current waveform in the field, compared with internationally allowable voltage unbalance limits.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.375-378
• /
• 2007

In these days, Korea Railway apply simple catenary system to general lines and high speed lines of Korea Electric Railway. Circulation Current in catenary system frequently bring undesirable consequences. Namely, the Connector wire has many problems according to a flow of excessive circulation (or traction current) and a sudden rise of temperature on catenary when electric car or locomotive is running in high speed. The occurrence of events by the load increasement do considerable damages to peoples, organizations and systems. On a case by case accidents, the reeltype protective cover as part of various methods has some problems. In this project, we proposed the improved changes on the catenary system of a improvement and change of a messenger wire protector, improvement of connector wire's institution angle and of a replacement the connector wire with a dropper. Its tridimensional space limitation dictated the scale of the $32{\times}{\Phi}55$ to be as small as possible. It is easier to install than work by the existing cover on the messenger wire.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.3 no.3
• /
• pp.184-190
• /
• 1998

Most buildings and factories are supplied with electric power by three-phase four-wire low voltage electric distribution system. This method pollutes the neutral line and utility sources with harmonic currents. Today, development of power conversion technology and the popularization of computer cause the neutral current to become serious. In this paper, a novel three-phase four-wire active filter is proposed to solve these harmonic problems has two purposes. The first purpose of the proposed active filiter is that the phase current has a sinusoidal waveform shape under the nonlinear load. The second purpose of the proposed active filiter is that the current on the neutral line become zero under the unbalanced power source and under the varring load conditions. The ability of the shunt active filiter has been proved to be excellent through simulations under the varring load conditions.