• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.205-209
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• 2015

The economic losses resulted from the accident in the power cables at the power station is not only huge but also requires a great amount of time and expenses to restore to the former condition. In order to prevent these, it is necessary to invent and apply a technique to expect and prevent the accidents. In order to measure insulation resistances of power cables in operation, we derived the relations between load current and temperature. By analyzing data obtained from our measuring equipments, we showed the expected time to change deteriorated cables before accident occurs. We present a result of our study on the effects of the load current on lifetime of 6.6 kV cable systems in operation. With the current flowing through the load of the cable a heat is generated reducing the lifetime of the cable. In order to find out the effect of load current on the lifetime of cable systems, we applied the lifetime theory to the development of two equipments to measure insulation resistance and current of cable systems in operation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.557-563
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• 2007

Rain-wind induced cable vibration can cause serious problems in cable-stayed bridge. External dampers attached to the cables have become widely accepted as an effective means for stay-cable vibration suppression. For very long stay-cables, however, such damper systems are rendered ineffective, as the dampers need be attached near the end of cables for aesthetic reasons. A recent study by the authors proposed that a movable anchorage system is replaced direct fixed support of the cable with a support through a bearing and damper. This paper extends the previous work by adding active control system to mitigate the cable vibration. The response of a cable with the proposed active control system is obtained and then compared to those of the cable with and without an external passive damper. The results show that the active control system can provide superior protection than the passive control system for a cable vibration.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.207-212
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• 2017

The cables installed to deliver high electric power from a generator at a thermoelectric power station are XLPE (or CV) cables. Depending on the installation and usage conditions, the cables in operation start deteriorating from the time of initial operation. Some cables can cause accidents due to faulty construction or other environmental factors. In order to prevent cable accidents, regular auditing of power cables is required. We have invented a measuring device for systematic surveillance and prevention of accidents, and installed the device at Korean Western Power Co. Ltd. which measures load currents through the cables. In this paper, we present the load current measured using our device, analyze the load characteristics by measures current, compare the ampacity defined by IEC standard, and present a basic data to obtain the temperature of cable conductors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.197-201
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• 2017

The demand for electric power is increasing every year in Korea. All the systems adopted at power stations in order to generate and transmit electric power should operate in perfect condition or reliability. The device for transmitting the generated high-voltage electric power is 6 kV CV single core cables. The manufacturing companies of the cables makes an official announcement that the operating lifetime of their cables is about 30years. But from the moment of operation the deterioration precesses of worsening the characteristics of cables starts. Since the reliability for the status of installed cables in deterioration has not been diagnosed, the cables can be broken at any unexpected moments. In order to prevent the abrupt cable accident by systematically monitoring the cable status, we have invented the first device in Korea. We have installed our device at Korea Western Power Co. Ltd. in order to diagnose the live cables. In this paper, we present our research results of measured temperatures of inner conductor and surface and the compared results of those data with other cable company. We also show that our results agree with those made by other company.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1156-1163
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• 2014

In this work by measuring transfer impedance of communication cables using EN50289 its Shielding effect is analyzed. transfer impedance measurement triaxial method using EN50289 is defined in CENELEC, it is unlike triaxial method prescribed in IEC Standard 96-1, can be measured regardless of diameter of coaxial cable and outer conductor. in this paper, transfer impedance measurement device of coaxial cable is designed and made according to EN50289 standard, The analysis determines the reliable working frequency range of coaxial cable and examined the impact of different shielding methods on coaxial cable. The transfer impedance measurements show considerable variations in results with various shielding methods. also the measurement procedure is verified through comparison of calculated and measured transfer impedance of RG-58 cable.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.1
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• pp.60-67
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• 2014

In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.93-101
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• 1989

A geometrically nonlinear cable finite element is presented to use in the static or dynamic modeling of offshore and onshore structures such as guyed tower, tension leg platform or mooring buoy, submarine cable, cable-stayed bridge, suspension bridge, cable roof and so on. The cable finite element is derived directly from the compatibility equations and flexibility matrix of elastic catenary cable theory for the arbitary plane loading and geome try. A general and virsatile computer program has been developed to perform the analyses of cable member itself or cable guyed or suspened structures, in which Newmark-$\beta$ method is used to obtain a time domain solution and Newton-Raphson iteration method is used to solve the nonlinear system of compatibility equations of cable and algebraic static or dynamic equations at each time step. The results from the static and dynamic analysis of a cable member by the computer program are summarized and presented.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.93-100
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• 2014

This study presents the recomposition of MBM (measurement-based model) using natural frequencies and modes from the usually measured data, and the evaluation of cable tension in service from the analysis results upon MBM of existing CSB (cable stayed bridge). The cable tension is shown to be different according to the position attached to cable and loading type. The measured cable tensions are not different distinctly according to position attached cable under dead and live loads, but larger than those under design loads. The distribution of cable tension calculated upon the MBM is similar to those of measured tension although the former is more than those of cable tension upon the design model. Considering to long-term behaviors of cable, therefore, the design of cable in CSB needs to apply the analysis results on MBM. For this purpose, future study needs lots of measured data and MBM is used to analyze the long-term behavior of cable in CSB.

• Journal of Korean Society of Steel Construction
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• v.19 no.2
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• pp.147-160
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• 2007

In this paper, we described the aeroelastic full-bridge model tests that were conducted to investigate the effect of alternative temporary stabilizing measures for thecable-stayed bridge during construction to ensure aerodynamic stability in the event of a typhoon or similar disasters. The effect of alternative temporary stabilizing measures was investigated through various configurations on two cable-stayed bridges with a main span of 475 m and 230 m, respectively. To investigate the bridge's aerodynamic behaviour and dynamic wind force during construction, the deflections at the end of the cantilever, the accelerations atthe top of the pylon and the moments at the lower part of the pylon were measured. As the result, the system with two sets of vertical cables per cantilever seemed to be the overall most effective solution, but the system with single vertical cable may also work. The combined system using the caisson support and vertical cables and the system with two sets of inclined cables per cantilever on the same anchor block may also be a solution. The inclined cables from the caisson to the girder were effective for some early stages of erecting the deck.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.48-59
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• 2019

In recent years, the type of bridge where cables such as suspension bridge and cable-stayed bridge are the main factors in the construction of long-range bridges has been soaring. The effects of cables on these structures are very large, and for structural analysis, it is necessary to study the cable and the structural changes according to the mode characteristics of the cables. In particular, cables are directly connected to camber adjustment, which conveys load effects on girders to tower, and are important components in the overall structure, and since the initial tension on the construction is compared with the tension over time, this study was conducted to help identify the condition of the bridge's aging and abnormalities. Therefore, in this study, the characteristics of the mode from the mode analysis through the impact hammer to the mass of the cable and the change in the length of the cable are analyzed.