• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.05c
• /
• pp.96-100
• /
• 2001

We have measured the space charge distribution and PD patterns simultaneously in XLPE under AC voltages by modified PEA method in order to investigate the effect of space charge on PD patterns in XLPE with air-gap. From the experimental results, we found that the dynamic space charge accumulated on the surface of XLPE due to the PD dominantly affects the PD pattern in the dielectric-barrier structure and governs the voltage across the air-gap. Moreover, the space charge formed by applying DC voltage still remained after applying AC voltage, which means that the space charge formed during DC strength test is likely to be fatal to the long-time AC insulating characteristics of HV equipments. On the other hand, the PD patterns was much influenced by the pre-formed space charge by DC application. Therefore, it is possible to detect the effects of space charge by monitoring the infinitesimal change of PD patterns before and after DC strength.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.10a
• /
• pp.319-322
• /
• 2008

This paper introduces experimental investigates of an accident pattern for the distributing XLPE cable terminations considering PL law environment. The influence of defects such as thickness and length decrease of XLPE, the impurity on XLPE and the gap between stress-con of housing and semi-conductor on insulating properties of the termination have been studied. The thickness and length decrease of XLPE decrease ac breakdown strengths. Dielectric breakdown traces of XLPE that is damaged by knife displayed other shape. The gap of between housing and semiconductor deteriorates dielectric strength of XLPE seriously.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.05b
• /
• pp.142-145
• /
• 2004

In this paper, we researched the dielectric properties and voltage dependence on slice XLPE sheet from 22[kV] and 154[kV] power cable. studied effect for impurities and water for semiconductive shied through a dielectric properties experiment to estimate performance of insulating material in power cable. Capacitance and $tan{\delta}$ of 22[kV], 154[kV] were 52/42 pF and $7.4{\times}10^{-4}$, $2.1510^{-4}$, respectively. In these results, the trend was increased with the increase of temperature. The $tan{\delta}$ of XLPE/semiconductive layer and XLPE/water/semiconductive layer were increased as compared with that of XLPE. dielectric properties reliability of $tan{\delta}$ was small.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.5
• /
• pp.185-190
• /
• 2016

The high-power 6.6 kV XLPE (or CV) cables at Korean electric power stations have been in operation for the last 40 years. Most of the XLPE cables starts deteriorating in 6-8 years from the operating instant of time, some cables may be breakdown at any moment even though they were installed in recent years, causing, huge socioeconomic losses. In order to prevent unexpected cable accident, the operating status of power cables should be monitored in regularly, timely bases. We have invented a device in order to systematically monitor and prevent an abrupt accidents of high-power cables in operation at power station. It has been installed at Korean Western Power Co. Ltd. at Taean, and operating normally for the last 4 years. In this paper, we introduce the functions and operating principles of the measuring device, and present the relationship between humidity and insulation status of XLPE cables for the load of electric turbine generator.

• Congress of the korean instutite of fire investigation
• /
• 2010.12a
• /
• pp.63-79
• /
• 2010

It is found to the arc trace on the junction termination of 345kV cable. According to the analysis of the cable material is judged to be good. Manufacturing and design problems are not considered. In construction defects, it was estimated to the low level of insulation oil. In the majority of the arc trace appeared XLPE is found. However, there is no Soots mark, yellow band has not been confirmed, not associated with a radial arc of the spider leg is not evidence. In other opinions, void, contamination or jut are not found on the inside of XLPE. Thus, by the attachment of the impurities in surface of XLPE insulation is judged to the breakdown.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.5
• /
• pp.213-221
• /
• 2002

In order to improve the reliability of XLPE cables, it is necessary to find the useful diagnostic parameter according to long term aging. This paper described the change of partial discharge(PD) phase Properties of XLPE cable insulation with branch type electrical tree degradation. for long term aging. To understand the PD Properties with $\phi$ -q-n distributed shape of XLPE insulation, specimens were prepared by 22.9㎸ distribution cable and made in a type of block(16${\times}$16${\times}$3[mm]). Ogura needles having tip radius of l0${\mu}{\textrm}{m}$ were inserted into each block pieces. The measuring system was consisted of PD detector, digitizer for digital conversion, VXI system for signal processing. The PD properties of the specimens were measured from initiation of tree to breakdown and their characteristics were analyzed. We analyzed the relationship between electrical properties(PD Quantity, PD initiation angle, PD extinction angle, PD occurrence angle : (PD extinction angle - PD initiation angle)) and the normalized aging rate. We found PD parameter, PD initiation angle and occurrence angle, which are a useful diagnostic parameter in estimating the branch type electrical tree for XLPE insulation condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.5
• /
• pp.90-95
• /
• 2004

This paper simulated partial discharge caused by 22.9[kV] power cable using XLPE(Peroxide Crosslinkable Polyethylene) insulation having the outside damage. As one of the insulation diagnostic method a radiated electromagnetic waves were measured by an UHF method using a BiconiLog antenna(EMCO-3142) and a spectrum analyzer used to measure EMI, EMC. From results of this study, It was confirmed that discharge Ogress were possible to be estimated by the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.9
• /
• pp.1644-1651
• /
• 2010

VLF $tan{\delta}$ diagnosis technology is introduced in IEEE Std 400 and proposed as evaluation criterion in an effective way of detecting water tree which mainly causes the failure of XLPE insulated cables. In order to inspect the accuracy of the VLF $tan{\delta}$ method for XLPE insulated power cables in Korean distribution system, diagnosis for 41 cables which were being serviced in the fields has been carried out and they were removed for AC breakdown voltage test after. Regarding the 41 cables, it was hard to confirm any relation between the VLF $tan{\delta}$ values and AC breakdown voltages and also water tree in the insulation was not detected. However, the other cables were failed several days after the diagnosis of the 41 cables. Water trees were found and their VLF $tan{\delta}$ values were also much higher than the criterion of IEEE standard. It has been ascertained that we need to change the IEEE criteria in order to improve the accuracy of detecting water trees by additional analyzing of field examples of failure and case studies from overseas countries and therefore amended VLF $tan{\delta}$ test voltage and evaluation criteria have been proposed.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1393_1395
• /
• 2009

지중송전라인에서 전압등급의 상승은 선로손실을 줄이면서 밀집된 전력수요에 대응하거나 특별히 고전압 수요를 맞추기 위한 것으로 이것은 XLPE Cable의 제조기술이 향상되면서 지속적으로 진행되어온 초고압송전계통의 일반적 추세이다. 이러한 경향으로 국내에서는 지중송전선로로서 최고전압인 345kV가 시공되어 운전중에 있으며 해외에서는 220kV~275kV급을 넘어서 400kV급 초고압케이블라인의 수요가 증가하고 있는데, 이러한 지중송전라인의 초고압화는 높은 신뢰성이 함께 요구되며 특히 접속재 분야에서 매우 높은 신뢰성이 요구된다. 당사는 UAE 400kV AL TAWEELAH Project에 400kV XLPE 1Cx630SQ 광복합 초고압송전라인을 준공하였는데 본고에서는 여기에 적용된 400kV XLPE 1Cx630SQ 광복합 케이블 부속재의 신뢰성을 높이기 위한 설계방법, 시험 및 시공에 대하여 요약하였다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.1
• /
• pp.75-81
• /
• 2018

In this study, the simulation of partial discharge pulse waveform have been performed for the typical joints such as EBA and PMJ in the HV underground transmission XLPE cable system in order to improve the understanding of partial discharge pulse waveform and the on-site measurement accuracy of partial discharges. FDTD simulation technique was adopted for the simulation and has been shown to be suitable for partial discharge simulation of power cables in terms of pulse propagation characteristics and waveform formation. The simulation results for the EBA showed that the second not-so-large opposite polarity peak appeared after the first negative polarity peak and the measurement sensitivity was the highest near the bottom of the EBA copper box. In the analysis results for PMJ, the magnitude of the second opposite polarity peak was large enough to compare with the first peak, and the measurement sensitivity at the end of the PMJ copper box was the highest. These simulation results show considerable similarity with the on-site measurement, and it would be very useful for the partial discharge measurement of HV XLPE cable systems.