In recent years,the issue of defects in the buffer layers of high-voltage cables has garnered significant attention due to their widespread occurrence and the substantial potential damages they pose.Although progress ...In recent years,the issue of defects in the buffer layers of high-voltage cables has garnered significant attention due to their widespread occurrence and the substantial potential damages they pose.Although progress has been made in understanding the mechanisms behind these defects and in developing detection methods,effective repair solutions remain limited.This study addresses this challenge by proposing a novel repair material:a two-component,additive liquid silicone rubber-based compound that utilises vinyl silicone oil as its base.The electrical,thermal,and mechanical properties of the cured silicone-based repair fluid are thoroughly analysed.To evaluate its effectiveness,an experimental platform was constructed using a 17-m-long,110 kV retired cable with known buffer layer defects.A specialised injection process was developed to facilitate the application of the repair fluid.The thermal characteristics,buffer layer voltage distribution,and partial discharge behaviour of the defective cable were analysed both before and after the repair.The results indicate that following the repair,the cable's heat dissipation capacity under full load increased by 6.25%.Additionally,the buffer layer voltage at the rated voltage(U0)decreased from 1.97 to 0.34 V,representing an 82.74%reduction.Notably,no partial discharge signals exceeding background noise were detected postrepair.This study demonstrates the effectiveness of the addition-cure liquid silicone rubber-based semi-conductive material in repairing cable buffer layer defects and provides valuable experimental support for its practical application in engineering.展开更多
Indonesian National Electricity Company （PT.PLN （Persero）） has planned to install additional high voltage undersea cable for circuit llI and IV Java-Bali to fulfill electricity demand in Bali. This project was mor...Indonesian National Electricity Company （PT.PLN （Persero）） has planned to install additional high voltage undersea cable for circuit llI and IV Java-Bali to fulfill electricity demand in Bali. This project was more prefered compared to building another power plant in Bali which could raise social and cultural resistance. Life cycle cost method was used to complete the financial feasibility study to ensure if the project has economic benefit, and the asset would be used effectively and efficiently along its benefit period. In this paper, a life cycle cost will be simulated to analyze which alternative is the most profitable： installation circuit III and IV in 2012 or installation circuit III in 2012 and circuit IV in 2017 in accordance with load forecasting demand. This study is used to help the management to make a decision about the project.展开更多
The air gap at the interface inside the cable terminations for high-speed trains and the partial discharge caused by it are two important factors affecting the insulating performance.The development of air gap and par...The air gap at the interface inside the cable terminations for high-speed trains and the partial discharge caused by it are two important factors affecting the insulating performance.The development of air gap and partial discharge will eventually lead to breakdown faults.To investigate the evolutionary characteristics of the air gap and partial discharge,the simulation models and samples of cable terminations containing defects are constructed in this paper.By analysing the variation law of the electric field and the multidimensional information of partial discharge,the evolution process of the air gap is divided into four wellcharacterised stages.Especially in the third stage,the partial discharge extinction voltage is 51.41%lower than that of the defect-free samples and even lower than the working voltage.The asymmetry of discharge is the most significant factor.The volume of discharge in the third quadrant is significantly higher than that in the first quadrant.This important feature can be applied to the inspection and evaluation of the insulating state of the cable terminations.The partial discharge characteristics of the air gap revealed in this paper are proposed to provide an important theoretical supplement to the study of interface discharges between heterogeneous dielectrics.展开更多
In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE inte...In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE interface involves the accumulation of opposite charges on both sides of the interface,thereby complicating the comprehension of the interfacial charging phenomenon.This study investigates the fundamental mechanisms of charge accumulation and the associated homo-junction effect in homo-bilayer XLPE(H-XLPE).Space charge analysis,model calculations based on Maxwell's equations,and thermal stimulation depolarisation current(TSDC)measurements were performed.Space charge results show that the homo-junctioninduced charge accumulation causes greater electric field distortion,leading to lower breakdown strength of H-XLPE compared to single-layer XLPE.Model calculations indicate that the density of opposite charges on the interface is attributed to the local gradient of reciprocal conductivity in the H-XLPE interface region.TSDC measurements on XLPE and H-XLPE enabled extraction of trap parameters and analysis of the charge transport process.The findings provide experimental evidence and theoretical clue for elucidating the role of the interface area on the charge accumulation that affects reliability and stability of submarine cable systems.展开更多
基金Guangdong Key Laboratory of Efficient and Clean Energy Utilization,South China University of Technology,Grant/Award Number:2008A060301002Basic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Number:2022A1515012523。
文摘In recent years,the issue of defects in the buffer layers of high-voltage cables has garnered significant attention due to their widespread occurrence and the substantial potential damages they pose.Although progress has been made in understanding the mechanisms behind these defects and in developing detection methods,effective repair solutions remain limited.This study addresses this challenge by proposing a novel repair material:a two-component,additive liquid silicone rubber-based compound that utilises vinyl silicone oil as its base.The electrical,thermal,and mechanical properties of the cured silicone-based repair fluid are thoroughly analysed.To evaluate its effectiveness,an experimental platform was constructed using a 17-m-long,110 kV retired cable with known buffer layer defects.A specialised injection process was developed to facilitate the application of the repair fluid.The thermal characteristics,buffer layer voltage distribution,and partial discharge behaviour of the defective cable were analysed both before and after the repair.The results indicate that following the repair,the cable's heat dissipation capacity under full load increased by 6.25%.Additionally,the buffer layer voltage at the rated voltage(U0)decreased from 1.97 to 0.34 V,representing an 82.74%reduction.Notably,no partial discharge signals exceeding background noise were detected postrepair.This study demonstrates the effectiveness of the addition-cure liquid silicone rubber-based semi-conductive material in repairing cable buffer layer defects and provides valuable experimental support for its practical application in engineering.
文摘Indonesian National Electricity Company （PT.PLN （Persero）） has planned to install additional high voltage undersea cable for circuit llI and IV Java-Bali to fulfill electricity demand in Bali. This project was more prefered compared to building another power plant in Bali which could raise social and cultural resistance. Life cycle cost method was used to complete the financial feasibility study to ensure if the project has economic benefit, and the asset would be used effectively and efficiently along its benefit period. In this paper, a life cycle cost will be simulated to analyze which alternative is the most profitable： installation circuit III and IV in 2012 or installation circuit III in 2012 and circuit IV in 2017 in accordance with load forecasting demand. This study is used to help the management to make a decision about the project.
基金supported by National Natural Science Foundation of China,Grant/Award Number:52377161.
文摘The air gap at the interface inside the cable terminations for high-speed trains and the partial discharge caused by it are two important factors affecting the insulating performance.The development of air gap and partial discharge will eventually lead to breakdown faults.To investigate the evolutionary characteristics of the air gap and partial discharge,the simulation models and samples of cable terminations containing defects are constructed in this paper.By analysing the variation law of the electric field and the multidimensional information of partial discharge,the evolution process of the air gap is divided into four wellcharacterised stages.Especially in the third stage,the partial discharge extinction voltage is 51.41%lower than that of the defect-free samples and even lower than the working voltage.The asymmetry of discharge is the most significant factor.The volume of discharge in the third quadrant is significantly higher than that in the first quadrant.This important feature can be applied to the inspection and evaluation of the insulating state of the cable terminations.The partial discharge characteristics of the air gap revealed in this paper are proposed to provide an important theoretical supplement to the study of interface discharges between heterogeneous dielectrics.
基金supported by Program of Beijing Huairou Laboratory(Grant ZD2022003A).
文摘In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE interface involves the accumulation of opposite charges on both sides of the interface,thereby complicating the comprehension of the interfacial charging phenomenon.This study investigates the fundamental mechanisms of charge accumulation and the associated homo-junction effect in homo-bilayer XLPE(H-XLPE).Space charge analysis,model calculations based on Maxwell's equations,and thermal stimulation depolarisation current(TSDC)measurements were performed.Space charge results show that the homo-junctioninduced charge accumulation causes greater electric field distortion,leading to lower breakdown strength of H-XLPE compared to single-layer XLPE.Model calculations indicate that the density of opposite charges on the interface is attributed to the local gradient of reciprocal conductivity in the H-XLPE interface region.TSDC measurements on XLPE and H-XLPE enabled extraction of trap parameters and analysis of the charge transport process.The findings provide experimental evidence and theoretical clue for elucidating the role of the interface area on the charge accumulation that affects reliability and stability of submarine cable systems.
