Yang Yan, Ma Jielin, Yap Malvern, Wang Qi, Chern Wen Kwang, Foo Yi Shyh Eddy, Chen Zhong
SP Group-NTU Joint Laboratory, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Singapore Power Group, Singapore 349277, Singapore.
Polymers (Basel). 2023 Apr 19;15(8):1942. doi: 10.3390/polym15081942.
In this study, we conducted the hygrothermal aging of an epoxy composite insulation material at 95% relative humidity (RH) and temperatures of 95 °C, 85 °C, and 75 °C. We measured electrical properties, including volume resistivity, electrical permittivity, dielectric loss, and breakdown strength. It was found to be impossible to estimate a lifetime based on the IEC 60216 standard, because it uses breakdown strength as its criterion even though breakdown strength hardly changes in response to hygrothermal aging. In analyzing variations in dielectric loss with aging time, we found that significant increases in dielectric loss correlated well with lifetime prediction based on the mechanical strength of the material, as described in the IEC 60216 standard. Accordingly, we propose an alternative lifetime prediction criterion by which a material is deemed to reach its end of life when its dielectric loss reaches 3 and 6-8 times the unaged value at 50 Hz and low frequencies, respectively.
在本研究中，我们对一种环氧复合绝缘材料进行了湿热老化试验，试验条件为相对湿度95%，温度分别为95℃、85℃和75℃。我们测量了包括体积电阻率、电容率、介电损耗和击穿强度在内的电学性能。结果发现，基于IEC 60216标准无法估算其寿命，因为该标准以击穿强度为判据，而击穿强度几乎不会因湿热老化而发生变化。在分析介电损耗随老化时间的变化时，我们发现介电损耗的显著增加与基于IEC 60216标准中所述材料机械强度的寿命预测具有良好的相关性。因此，我们提出了一种替代的寿命预测判据，即当材料在50Hz和低频下的介电损耗分别达到未老化值的3倍以及6 - 8倍时，认为该材料达到其寿命终点。
