• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1455-1457
• /
• 2002

The real-time dynamic rating system(DRS) can provide the maximum ampacity within required periods, so it can help the transmission-line operation more safely and efficiently. Because the conductor temperature is the main limit of increasing rating current, conductor temperature monitoring(CTM) technology is the basic to DRS. In this paper, real-time CTM was developed for 345kV XLPE cable in tunnel and we have also compared the CTM result of this study with the result according to IEC 287 and JCS 168 thermal parameters.

• Tunnel and Underground Space
• /
• v.5 no.1
• /
• pp.70-76
• /
• 1995

Two types of deformations can occur on the cable during the monitoring of the rock displacement by the time domain reflectometry. One is the impedance model for tensile deformation, and the other is the capacitance model for the shear deformation. The former gives a response signal with a gradual change in the amplitude of the reflected voltage, meanwhile the latter produces a signal with a blunted spike. The resolution of the TDR can be improved to 0.125% using calibration crimps on the cable of 60 meters long. It is recommended that the diameter of the cable should be 18 mm at least in order to induce a better reflected pulse without any open-circuit. The actual TDR technique cannot characterize the type and the magnitude of rock displacement quantitatively. Systematic investigation of the TDR parameters, such as the exact of cable diameter, cable length, number of crimps, combination of shearing and extension, and environment of the TDR equipment, will be able to improve the resolution to 0.01 mm.

• Structural Engineering and Mechanics
• /
• v.41 no.1
• /
• pp.139-155
• /
• 2012

Structural health monitoring systems are often installed on bridges to provide assessments of the need for structural maintenance and repair. Damage or deterioration may be detected by observation of changes in bridge characteristics evaluated from measured structural responses. However, construction materials such as concrete and steel cables exhibit certain time-dependent behaviour, which also results in changes in structural characteristics. If these are not accounted for properly, false alarms may arise. This paper proposes a systematic and efficient method to study the time-dependent effects on the dynamic properties of cable-stayed bridges. After establishing the finite element model of a cable-stayed bridge taking into account geometric nonlinearities and time-dependent behaviour, long-term time-dependent analysis is carried out by time integration. Then the dynamic properties of the bridge after a certain period can be obtained. The effects of time-dependent behaviour of construction materials on the dynamic properties of typical cable-stayed bridges are investigated in detail.

• Journal of Korean Association for Spatial Structures
• /
• v.11 no.2
• /
• pp.71-79
• /
• 2011

Due to the self-equilibrium status of the cable system, the loss of the tensioning in the cable system results in other cables carrying larger tension forces than those initially calculated by structural engineers. Also, turn-buckle systems, which have been widely used to pre-tension and/or re-tension the cables, are limited to use for small cables and to provide a rough estimation for tension forces. In this study, the re-tensioning cable connection systems were developed to overcome the problems mentioned above. The main objective of the proposed system is to re-tension large cables and measure the exact amount of tension forces of the cable systems. This connection system is also combined with the wireless signal monitoring module so that engineers are able to measure the tension forces any place where the internet is available. This paper presents the development of the re-tensioning cable connection systems and experiment using the real-scale cable systems to verify the fe-tensioning and signal monitoring systems.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.1
• /
• pp.239-245
• /
• 2013

The temperature monitoring of power cable and cable junction point is the necessary link of the safe and reliable operation of the power system. Many kinds of cables and high voltage junction points are easy to exposed continuous vibrations and momentary impulse in industry field especially power plant industries. This system can predict the overheating of the electric cable interface and the possibility of all kinds of accident, and it helps for eliminating the hazards of electric cable interface and provides the effective guarantee for the safety operation. In order to avoid the faults of the inconvenience of installation and maintenance and the high cost of application, this system used small and contactless IR sensor module. The low power consumption is used in the system. The goal of this study is the low cost and on-line reliable monitoring of power cable and junction point temperature.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.7
• /
• pp.592-602
• /
• 2013

The purpose of this study is to optical cable closure and fiber line monitoring system. The current optical cable closure cases have not had any systems that help the central control station recognize opening as well as closing the cases in real-time when opening B2B and B2C lines. to solve this problem, it is considered to create systems that go off alarms, real-time fault location immediately, set alarms for open and close monitoring optical cable closure, and inspect regularly whether optical cables are deficient when monitoring the optical line in real-time and cutting them, in this paper, the monitoring system whose the central control station finds an optical signal block immediately and goes off the alarms when line workers separate components like a connector or a tray from the optical cable closure through OTDR. this study can contribute to stabilize the network quality through the quick and effective operation of the cables.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.939-942
• /
• 1998

This paper presents the process on the construction for the remote distribution pole transformer monitoring system. Especially, this system uses CATV cable as communication media which is located in KEPCO's main distribution line. It has four major components such as sensor for measuring secondary voltage and currents of distribution transformer, RF modem for data modulating/de-modulating, communication media for sending/receiving of data, and pc server for monitoring the results of sensing or computing information. This paper also describes the configuration of these each component's configuration and its functions.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39A no.6
• /
• pp.357-364
• /
• 2014

In this paper deals with PON Remote monitoring solution using Reflecting Filter. The current FTTH-PON can not be monitored in real time that Optical cable fault and Quality degradation of Splitter. To solve this problem, Monitoring can make Feeder Network and Splitter that Reflecting filter development using the basic structure of Fiber Bragg grating. Reflecting Filter is Quality Monitoring System shall provide tools for user to view and analyze degradation of cables and splitter in particular predict any gradual component degradation(Optical cable bending, splice, connector, etc) before it becomes service impacting. The Reflecting Filter solution is splitter down and confirm the fault location of optical cable and it will send central control station can be monitored system an alarm to the OLT. In other words, wavelength side branches Mating existing communication affairs (Coupler) using the core of one optical wavelength for live monitoring two wavelengths and sends the subscriber side modem and aggregation switch device remotely using a reflective optical line filter monitoring the study of the system. this study can development of Reflecting filter improve the average processing time of Optical cable fault and efficient Maintenance of the network.

• Smart Structures and Systems
• /
• v.30 no.6
• /
• pp.661-671
• /
• 2022

Stayed cables are the key components for transmitting loads in cable-stayed bridges. Therefore, it is very important to evaluate the cable force condition to ensure bridge safety. An online condition assessment and anomaly localization method is proposed for cables based on the spatiotemporal correlation of grouped cable forces. First, an anomaly sensitive feature index is obtained based on the distribution characteristics of grouped cable forces. Second, an adaptive anomaly detection method based on the k-nearest neighbor rule is used to perform dissimilarity measurements on the extracted feature index, and such a method can effectively remove the interference of environment factors and vehicle loads on online condition assessment of the grouped cable forces. Furthermore, an online anomaly isolation and localization method for stay cables is established, and the complete decomposition contributions method is used to decompose the feature matrix of the grouped cable forces and build an anomaly isolation index. Finally, case studies were carried out to validate the proposed method using an in-service cable-stayed bridge equipped with a structural health monitoring system. The results show that the proposed approach is sensitive to the abnormal distribution of grouped cable forces and is robust to the influence of interference factors. In addition, the proposed approach can also localize the cables with abnormal cable forces online, which can be successfully applied to the field monitoring of cables for cable-stayed bridges.

• Structural Engineering and Mechanics
• /
• v.50 no.1
• /
• pp.37-52
• /
• 2014

The accurate determination of cable tension is important to the monitoring of the condition of a cable-stayed bridge. When applying a vibration-based formula to identify the tension of a real cable under sag, stiffness and boundary conditions, the resulting error must not be overlooked. In this work, by resolving the implicit frequency function of a real cable under the above conditions numerically, indirect methods of determining the cable force and a method to calculate the corresponding cable mode frequency are investigated. The error in the tension is studied by numerical simulation, and an empirical error correction formula is presented by fitting the relationship between the cable force error and cable parameters ${\lambda}^2$ and ${\xi}$. A case study on two real cables of the Shanghai Changjiang Bridge shows that employing the method proposed in this paper can increase the accuracy of the determined cable force and reduce the computing time relative to the time required for the finite element model.