The Influence of Temperature and Moisture on the Insulation Characteristics of 25kV XLPE Cable

• Main Authors: Kuo-Kuang Chen, 陳國光
• Other Authors: Ji-Maun Ho
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/97641686839991391572

碩士 === 中原大學 === 電機工程研究所 === 95 === This report introduces the structure and function of cable and accessories. In addition, this report also deals with potential environmental factors, aging mechanisms and effects resulting in insulation degradation of cables. The prime purpose is to use partial discharge (PD) measurement combining with insulation resistance measurement and dielectric loss measurement to detect the insulation status of cables and terminals under environmental stresses, to early find the aging indications of cables, and further to reach the purpose of predictive diagnosis. The method is to utilize a programmable temp. & humi. chamber and autotransformers to carry out two kinds of environmental qualification on twelve samples of 25kV XLPE cables. One is a synergistic experiment of temperarure and moisture. Another environment is in a constant ac voltage of 15kV rms with a 300A current switching regularly. In the process of environmental experiment, appling PD measurement, insulation resistance measurement and dielectric loss measurement to know the recognizition ability on internal defects of cables and to find the diagnostic methods available. The experimental results show among the PD measurement, insulation resistance measurement and dielectric loss measurement, PD measurement seems to have better performance to recognize internal defects of cables, but it’s easy to be disturbed by noise. Insulation resistance measurement has worst performance in internal defects detection. Dielectric loss measurement can combine with PD measurement applied in a wet environment to obtain the integral insulation states and internal defects of cables