The degradation of crosslinked polyethylene (XLPE) cable insulation during service, such as thermo-oxidation and water treeing may lead to a premature electrical breakdown of the XLPE insulation cables. Therefore, it ...The degradation of crosslinked polyethylene (XLPE) cable insulation during service, such as thermo-oxidation and water treeing may lead to a premature electrical breakdown of the XLPE insulation cables. Therefore, it is necessary to optimize the period of replacement to evenly distribute the replacement cost by ascertaining the deterioration degree. Estimation of the aging degree is at present the most important task for diagnosis of the residual lifetime of the power cable insulation. This paper presents a study on the changes in the dielectric properties of the thermally aged XLPE cables in the frequency range from 0.07～10 MHz. Based on electrical and physicochemical characterization, some new "dactylograms" for the thermally aged XLPE cable insulation have been proposed.展开更多
The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoiniti...The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, the optimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidation stability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique for producing photocrosslinked XLPE-insulated wire and cable is described in detail. It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.展开更多
The purpose of this paper is to investigate the effect of PD （partial discharge） activity within medium voltage XLPE （cross-linked polyethylene） cables. The effect of partial discharge was studied by means of a nu...The purpose of this paper is to investigate the effect of PD （partial discharge） activity within medium voltage XLPE （cross-linked polyethylene） cables. The effect of partial discharge was studied by means of a number of simulations. The simulations were based on the well-known three capacitor model for partial discharge. An equivalent circuit was derived for partial discharge due to a single void in the insulation material of a power cable. The results obtained from the simulations will form the basis of the design proses of a non-intrusive condition monitoring technique. The technique is based on the classification of discharge activity according to five levels of PD. Future work will include the improvement of the simulation model by investigating the high frequency model of a power cable as well as the statistical nature of PD activity. This will improve the accuracy of the simulation results when compared to actual measurements. The work discussed in this paper will be used to construct and calibrate a practical model which will make use of PD measurements for non-intrusive condition monitoring of medium voltage electrical cables.展开更多
基金Major Research Project of Shanghai City(No. 045211024)
文摘The degradation of crosslinked polyethylene (XLPE) cable insulation during service, such as thermo-oxidation and water treeing may lead to a premature electrical breakdown of the XLPE insulation cables. Therefore, it is necessary to optimize the period of replacement to evenly distribute the replacement cost by ascertaining the deterioration degree. Estimation of the aging degree is at present the most important task for diagnosis of the residual lifetime of the power cable insulation. This paper presents a study on the changes in the dielectric properties of the thermally aged XLPE cables in the frequency range from 0.07～10 MHz. Based on electrical and physicochemical characterization, some new "dactylograms" for the thermally aged XLPE cable insulation have been proposed.
基金The project was successively supported by the National Natural Science Foundation of China(No. 5880104, No. 59543002 and No. 59773030).
文摘The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, the optimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidation stability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique for producing photocrosslinked XLPE-insulated wire and cable is described in detail. It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.
文摘The purpose of this paper is to investigate the effect of PD （partial discharge） activity within medium voltage XLPE （cross-linked polyethylene） cables. The effect of partial discharge was studied by means of a number of simulations. The simulations were based on the well-known three capacitor model for partial discharge. An equivalent circuit was derived for partial discharge due to a single void in the insulation material of a power cable. The results obtained from the simulations will form the basis of the design proses of a non-intrusive condition monitoring technique. The technique is based on the classification of discharge activity according to five levels of PD. Future work will include the improvement of the simulation model by investigating the high frequency model of a power cable as well as the statistical nature of PD activity. This will improve the accuracy of the simulation results when compared to actual measurements. The work discussed in this paper will be used to construct and calibrate a practical model which will make use of PD measurements for non-intrusive condition monitoring of medium voltage electrical cables.
