Measurement of Activation Energy and Accelerated Degradation Time by Thermal Analysis Methods for Polymeric Insulating Materials

With the development of HVDC systems, there has been much research regarding insulating materials applied in the DC environment. Of particular concern is the degradation of electrical insulation due to external environmental factors caused by the long-term use of the insulation material of a power device. If such degradation continues, a leakage current may flow on the surface of the insulating material, eventually causing a partial discharge and potentially resulting in a major accident. Therefore, it is necessary to understand the long-term reliability of insulation materials. To do this, accelerated degradation tests and lifetime analyses should be performed by measuring the activation energy of insulation materials. There are currently various analytical methods to determine the activation energy, but the values obtained according to the different analysis methods vary. Because there are no established measurement criteria, it is necessary to accurately measure the activation energy of insulation materials. Therefore, in this paper, six analysis methods were performed through thermogravimetric analysis (TGA) to measure the activation energy, which was used to select the degradation time for the accelerated degradation test for which a reliable degradation time for acceleration degradation could be calculated. As a result of the experiment, deterioration acceleration time appeared in the order of PP > PE > PTFE > UPE, and accelerated deterioration of the insulating material through the deterioration time range measured in a future study will be performed to evaluate the life of each insulating materials.