Tools for Condition Monitoring of Polymeric Electrical Insulating Materials

Polymeric electrical insulating materials are essential for most electrical apparatuses from small electronic devices to large power equipment such as switchgear and electric cables. Therefore, their condition must be monitored adequately, and their degradation must be detected well before it becomes fatal. This report describes the condition monitoring tools that are versatile and powerful but not so commonly used to analyze ordinary insulating polymers. Their features are also explained, showing concrete examples. The tools cover electrical or electromagnetic methods with frequencies from zero to the THz range and light absorption and emission. Tools to examine the surface hardness of polymers are also included. The points to be aware of when estimating the remaining life using the Arrhenius plot analysis are noted.