• 한국정밀공학회지
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• 제16권9호
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• pp.166-171
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• 1999

An overhead crane system consists of trolley, girder, rope, object, trolley motor, girder motor, and hoist motor. An analytic model which derived from the modelling of the overhead crane system is nonlinear model which includes the swing and the twist angle of the object. this model consists of the equation of motion for motors and object. If the swing angle and the acceleration of Z for the object are small, this model becomes a simple nonlinear model which doesn't include the swing and the twist angle of the object. From the results of computer simulation, the characteristics of an actual overhead crane system could be predicted by the simple nonlinear model.

• 전기학회논문지
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• 제59권12호
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• pp.2135-2142
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• 2010

This paper studies the validity about a joint operation of neutral wire and overhead grounding wire in combined distribution systems. The overhead grounding wire and neutral wire are currently installed separately and grounded by common. However there is no any ineffectiveness or electrical problem in case of the proposed system, such system can be operated at real distribution system. Therefore this paper describes the suitability of a joint operation through lightning surge analysis on combined distribution systems. Lightning surge analysis is carried out by EMTP/ATPDraw to obtain the overvoltage of overhead line and underground cable in various conditions such as locations and current types of lightning stroke. Overvoltage gained by the analysis show that the insulation strength of the joint operation case is not stable compare with the current operation case.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.826-831
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• 2006

In this paper, we discussed the energy performance of underfloor air distribution(UFAD) and overhead air distribution system according to outdoor air intake rates in a office building. For this, the laboratory(S lab.) is selected for measuring the thermal environments of UFAD system and overhead system. Based on the measured data, the TRNSYS simulation is used to evaluate the energy performance of UFAD system and the overhead system according to outdoor air intake rates. By increasing outdoor air intake rates from required outdoor air intake rates(100CMH) to maximum air intake rates, the energy savings of UFAD system comparing with overhead system are varied $15%{\sim}25.6%$ in summer, $12.8%{\sim}19%$ in fall/spring and not varied in winter(8%). As results of simulations on stratification height and cooling set temperature, the lower the stratification height and the higher cooling set temperature, the larger cooling energy savings of UFAD comparing with overhead system according to outdoor air intake rates.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.204-205
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• 2006

This paper describes the protective ability of lightning arrestor in combined distribution system with power cable. To evaluate the protective ability, change of arrestor and grounding location are considered. On the other hand, arrestor developed by Cooper Power Systems for underground power cable system, is considered to evaluate surge protective ability as in underground system, when arrestor occurs failure has overhead line. The result shows that lightning arrestor in combined distribution system with power cable protect effectively when failure at arrestor in overhead line. On the other hand, arrestor developed by Cooper Power Systems for underground power cable system, is considered to evaluate surge protective ability in underground distribution system, when arrestor of overhead line has failure. The result shows that lightning arrestor installed in underground cable can effectively protected cables from surge when arrestor of overhead line has failure. And also even though grounding locations are decreased, it is revealed that protective ability is nearly similar.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.495-498
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• 2001

The distribution line through which electricity is supplied from substation to customer generally varies by underground line and overhead line. In contrast that the underground line is shielded, the overhead lines do not have the shield layer. To overcome this weak point of the overhead lines, the aerial bundled cable(ABC) connection systems have been developed. The basic concept of the ABC connection system is the application of the underground cable system containing complete shield layer to the overhead cable system. The ABC system is the innovative technologies which enable the prevention of electric shocks, reduction of the maintenance charge and damage of the cable. This paper give a full detail of vertical connection system applied within a country.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1248-1257
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• 2014

Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.112-117
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• 1997

This paper presents a GA(Genetic Algorithms)-Optical control strategy for the control of the swing motion and the transverse position of the overhead crane. The overhead crane system is defined uncertain due to unknown system parameters such as payload and trolly mass. To control the overhead crane. the GA-Optimal control scheme is suggested. which transfers a trolly to a desired place as fast as possible and minimizes the swing of the payload during the transfer. The genetic algorithms are applied to fine digital optimal feedback gains. A computer simulation demonstrate the performance of the proposed the GA-digital optimal controller for the overhead crane.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1366-1371
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• 2004

The development of the European railway high speed network brings new problems related to the interoperability across the railways of different countries. The pantograph and the overhead wire form a dynamic coupled system and they affect each other through the contact force. Unfortunately, as the operational speed of a train increases, the vibration of the pantograph and the overhead wire also increases. This may lead to a zero contact force between the pantograph head and the overhead wire, which can results in the loss of contact, arching and abrasion. If the arching and spark happen between the pantograph and the overhead catenary system, the EMI(electro magnetic interface) and noises may occur. After an, the quality of current collection is deteriorated. This paper describes the dynamic response between the pantograph and catenary system by the numerical simulations and predicts the possibility of operating the high speed train in the conventional lines.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2240-2245
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• 2003

In this paper, the controller design by coefficient diagram method (CDM) for controlling the trolley position, load-swing angle and hoisting rope length of the overhead crane system simultaneously is proposed. The overhead crane system is a MIMO system consisting of two inputs and three outputs. Its mathematical model is nonlinear with coupling characteristics. This nonlinear model can be approximated to obtain a linear model where the first input mainly affects the trolley position and the load-swing angle while the second input mainly affects the hoisting rope length. In order to utilize the CDM concept for assigning the controllers, namely PID, PD and PI controllers separately, the model is approximated to be three transfer functions in accordance with trolley position, the load-swing angle and the hoisting rope length controls respectively. The satisfied performances of the overhead crane system controlled by the these controllers and fast rejection of the disturbance effect occurred at the trolley position are shown by simulation and experimental results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.824-828
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• 2007

With increasing interest in the reduction of cost for operation and maintenance of overhead catenary system, various methods of condition monitoring have been developed and used in with high-speed analysis and advanced image processing techniques. This study utilizes a high-speed camera as inspecting system to measure the wear, stagger, hight and arc extinguishing test of overhead catenary system. All measuring image were captured by a high speed CMOS camera with PCI express output, which can acquire up to 1000 frames per second with the resolution 1024 × 1280 pixels. Line type laser source with a power equal to 300 mW and the National Instrument LabVIEW (8.0) based on vision acquisition software have been used in application programming interface for image acquisition, display, and storage. The proposed high-speed camera system is finally applied to measure the overhead catenary system showing promising on-field applications