• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.467-469
• /
• 2004

When power cables cross regions with unfavorable thermal conditions, conductor temperatures higher than the design value can occur. This paper proposes the calculation algorithms of the permissible current-carrying capability using the algorithm of calculating the longitudinal conductor temperature distribution of power cables installed in thermally dissimilar soil materials.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.256-258
• /
• 2002

This paper analyzes the sensitivity of the permissible current-carrying capability of underground power cables according to the thermal property of backfill materials and construction size of backfill materials. It is helpful for operators to determine the operating current and to design the construction of underground power cables.

• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.159-161
• /
• 2000

This paper examines the thermal circuit of underground tunnels installed power cables. It can be appreciated to understand the mechanism of heat transfer and to calculate the current carrying capacity of power cables in tunnel.

• Proceedings of the KIEE Conference
• /
• 2001.11b
• /
• pp.263-265
• /
• 2001

This paper proposes an analysis of an permissible current-carrying capability of being installed transsmission power cables and distribution power cables simultaneously.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.73-74
• /
• 2007

For a safe operation of HVDC systems, the fault location and clearance of faults in the HVDC lines are important. Past methods for fault location on HVDC cable depend on existence of assistance cables and fault resistance, broken cable and environment of fault location. For complement these problems, in this paper, fault location method using traveling wave and cross correlation function is proposed for HVDC cables. Voltage controlled source and current controlled source HVDC were modeled by EMTDC/PSCAD. The proposed algorithm were verified varying with fault distance, fault resistance.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.295-297
• /
• 1998

This paper shows characteristics of fault current division factor $S_f$, which is a ratio of earth- return current to total fault current, at a substation fed exclusively by power cables under unsymmetrical fault condition, such as single line-to-ground fault. In substation grounding system design, $S_f$ is a very important factor determining GPR, touch and step voltage at a substation under fault condition. In case of substations fed by overhead lines, 40-60% of $S_f$ has been typically used, although it is a very conservative value with no other network conditions considered. It is authors' hope that $S_f$ presented in this paper could hopefully be a basic reference in designing of substation grounding system, especially for a substation fed exclusively by power cables.

• Proceedings of the KIEE Conference
• /
• 1990.07a
• /
• pp.304-307
• /
• 1990

Referring to the calculation of the continuous permissible current rating in 22.9kV CN/CV underground distribution power cables, the current and temperature have been fully discussed and analyzed based on their three different values: one is the actually measured value throughout our test and the other two are calculated in connection with different specifications IEC-287 and JCS-168-D respectively. For this purpose, our test has been carried out with real cables which have been under stress either with induced current or with rating voltage. In the former, the calculated current of IEC-287 shows closer value to the measured one than that of JCS-168-D does. In the latter, there has been little difference on the temperature comparing with that measured without voltage application. Therefore, we think that it is preferable to choose the IEC-287 specification for the calculation of the continuous permissible current rating in the commercially power cables.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.8
• /
• pp.1632-1638
• /
• 2011

Electric cables are one of the most important components in a nuclear power plant since they provide the power needed to operate electrical equipment. Despite their importance, cables typically receive little attention since they are considered passive, long-lived components that have been very reliable over the years when subjected to the environmental conditions for which they were designed. The operating experience reveals that a defect of the insulator or poor construction causes the initial failure of cable. However, the number of cable failures increase with plant aging, and these cable failures are occurring within the plants' 40-year licensed period. These cable failures have resulted in plant transients, shutdown, loss of safety functions or redundancy, entries into limiting conditions for operation, and challenges for plant operators. Therefore, diagnosis of MV cable installed in NPPs has become one of the most urgent issues in recent years. In accordance with PSR, condition maintenance for cables is also continuously required. Recently, HFPD tests have been widely performed to diagnose cable in the transmission and distribution cable system. However, on-line HFPD wasn't used in the NPPs because of the danger of plant shutdown, measurement sensitivity and application problems, etc. In this paper, HFPD measurement with portable device was performed to evaluate the integrity of the 4.16kV & 13.8kV cable lines. The test results show that HFPD is highly attractive to the diagnosis of MV cables in NPP by high detection sensitivity on-site.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.253-255
• /
• 2002

The necessity of compact high temperature super conducting cables is more keenly felt in densely populated metropolitan areas. As the compact high temperature superconducting cables that can be installed in ducts and tunnels can reduce construction cost and make the use of underground space more effective, the effect of introducing it to power system will be huge. For this study, Seoul, Korea is selected as a review model, the loads are estimated by scenario based on a survey and analysis of 345kV and 154kV power supply networks in this area. Based on this, the following items on urban transmission system are examined. (1) A method of constructing a model system to introduce high temperature superconducting cables to metropolitan areas is presented. (2) A case study through the analysis of power demand is conducted, and the amount of high temperature superconducting cable to be introduced by scenario is examined. (3) The economy involved in expanding existing cables and introducing high temperature superconducting cables(ducts or tunnels) following load increase in urban areas is examined and compared. (4) The maximum external diameter of HTS cable to accommodate exiting ducts based on the design standards for current cable ducts is calculated. (5) The voltage level that can be accommodated by existing ducts is examined.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.6
• /
• pp.187-193
• /
• 2018

There has been a gradual increase in the demand for the electric power in Korea. In order to meet the demand, power station should have technical functions with increased effectiveness. When accident happens in electric machinery at power stations, huge amount of economic losses and mulfunction of equipments occur. One of the accidents is a deteriorated cables operating power stations. In order to prevent cable accident in advance, we should monitor the insulation status of the cable. Cable accidents are resulting from the junctions. We have developed and installed a device in order to identify the status of junction part of power cable at Korea Western Power Co., Ltd.. We performed an accurate diagnosis for the stable utilization of junctions where the accidents occurs most frequently, and to increase the reliability. In this paper, we present the concepts of our device and the method of monitoring diagnosis for the stable use of junctions at cables predicting the life time of cables by analyzing the data obtained by the device. We also present the hardware aspect of the device we have developed.