• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.22-25
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• 1987

New measurement method of coupled transmission line characteristics is described. This method presents precision calculated values of even- and odd-mode impedances and effective dielectric constants of mictostrip parallel coupled lines from the scalar quantities obtained by transmission coefficients at two different resonance frequencies. Measured impedances and effective dielctric constants are good agreement with predicted values.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.99-104
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• 2005

This paper describes the measurement and analysis of the basic line constants in PLC(Power Line Communication) in the residential building. An apartment is considered as one of the conventional residences to get the line constants in this paper, Agilent 4263B LCR Meter is used to measure the detailed values each area and the specific results and averaged analysis data are shown in the tables. The measured results are a little bit different from the calculated values using conventional formula due to the line arrangement, neglected factors, complex permittivity, and etc. This paper describes many kinds of lines and wiring figures of domestic construction. It can be utilized with the analyzed line characteristics in frequency domain as a planning reference of PLC.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.33-41
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• 2010

There are several overvoltages by abnormal conditions in power system. We need to calculate these ovevoltages for the insulation design and the fault analysis. For these calculations, we used EMTP(Electro-magnetic Transients Program). During EMTP calculations, the accurate modelling of the equipments is very important for analysis results. In this paper, we considered the effects of the modelling condition's changes for transmission line within EMTP modelling cases of overvoltage analysis. Specially, we considered CB closing cases of 765[kV] system. So, we had changed the calculation frequencies of Line Constants, which is used for CB closing cases. In addition, we compared the calculation result and the measured result.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.620-627
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• 2000

This paper presents a mettled to obtain line constants for a catenary system. To find them, voltages, currents and power factors according to frequencies were measured in short circuit and open circuit respectively. And front the measured data, resistances, inductances and capacitances were also calculated.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.103-118
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• 2018

When collision accident between ships or between ship and offshore platform occurs, a common phenomenon that occurs in structures is the plastic deformation accompanied by a large strain such as fracture. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is heated by line heating and steel plate formed by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper-Symonds model and Johnson-Cook model and the assumption that strain rate can be neglected when strain rate is less than the intermediate speed are verified through free drop test as well as comparing with numerical results in several references. This paper ends with describing the future study.

• International Journal of Railway
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• v.3 no.2
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• pp.46-53
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• 2010

Electric railroad systems consist of rolling stock, track, signal and catenary system. In the catenary system, one of the most important factors is the impedance according to the design and characteristic. Before the catenary system is designed, the impedance should be precedently researched. The railroad catenary system is complex system which is composed by five conductors. The five conductors classify up and down feeders, up and down contact wire group, rail group. Therefore, we should compose the catenary system of the equivalent five-conductors model. In this paper, we suggest a geometrical model and a equivalent conductor model by using geometric mean radius of five conductors in the catenary system. Also, we calculate demanded parameter values in the model. By using those, line constants of five conductors are analyzed by applying the equivalent method called as the condensed joint matrix.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.119-126
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• 1997

The relationship between the applied stresses and the change of elastic wave velocity has been established based on the acoustoelasticity theory. The non-uniform stress field in a loaded specimen has been evaluated from the surface acoustic wave velocity measured by the line-focus acoustic microscopy with the acoustoelastic constants obtained form a calibration test. The evaluated stresses are in good agreement with the results calculated by finite element method.

• Nuclear Engineering and Technology
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• v.36 no.6
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• pp.528-539
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• 2004

It is essential in commercial reactors that the safety limits imposed on the fuel pellets and fuel clad barriers, such as the linear power density (LPD) and the departure from nucleate boiling ratio (DNBR), are not violated during reactor operations. In order to accurately monitor the safety limits of current reactor states, a detailed three-dimensional (3D) core power distribution should be estimated from the in-core detector signals. In this paper, we propose a calculation methodology for detailed 3D core power distribution, using in-core detector signals and core monitoring constants such as the 3D Coupling Coefficients (3DCC), node power fraction, and pin-to-node factors. Also, the calculation method for several core safety parameters is introduced. The core monitoring constants for the real core state are promptly provided by the core design code and on-line MASTER (Multi-purpose Analyzer for Static and Transient Effects of Reactors), coupled with the core monitoring program. through the plant computer, core state variables, which include reactor thermal power, control rod bank position, boron concentration, inlet moderator temperature, and flow rate, are supplied as input data for MASTER. MASTER performs the core calculation based on the neutron balance equation and generates several core monitoring constants corresponding to the real core state in addition to the expected core power distribution. The accuracy of the developed method is verified through a comparison with the current CECOR method. Because in all the verification calculation cases the proposed method shows a more conservative value than the best estimated value and a less conservative one than the current CECOR and COLSS methods, it is also confirmed that this method secures a greater operating margin through the simulation of the YGN-3 Cycle-1 core from the viewpoint of the power peaking factor for the LPD and the pseudo hot pin axial power distribution for the DNBR calculation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.2
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• pp.139-143
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• 1988

A new measurement method of coupled transmission line characteristics is described. This method presents precision values of even-and odd-mode impedances as well as effective dielectric constants of symmetric parallel coupled microstrip lines from the scalar quantities obtained by transmission coefficients at two different resonance frequencies. Especially these values include dispersion effects in the measured frequency band. The measured impedances and effective dielectric constants of actually fabricated coupled lines on the Teflon substrates with low dielectric constants are good agreement with predicted values. And the experimental pass band characteristics of single section resonator by using previously designed coupled lines agree well with theoretical values.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.472-480
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• 2007

This paper analyzes overvoltage on testing line for various parameter effect examination. Model systems consist of overhead line and underground cable. The model considered actual characteristic data of distribution lines. and will be constructed at testing yard. The simulations were performed under various line configuration such as cable kinds, cable length, lightning wave, lightning wave time, transformer and branch circuits. The simulation models are established by EMTP/ATPDraw and Line Constants are calculated by ATP_LCC. When lightning surge strikes on conductor of overhead line, EMTP/ATPDraw calculates overvoltage in many cases. Simulation results will be compared with real testing results at testing yard. The compared results will be used to establish protection methods in actual underground distribution systems.