REVIEW OF CHEMICAL INDICATORS OF DEGRADATION OF CELLULOSIC ELECTRICALPAPER INSULATION IN OIL-FILLED TRANSFORMERS

Chemical and thermal degradation of electrical insulation in oil-fille d transformers, mechanisms of failure and methods of condition monitor ing and of life prediction are reviewed. An insulation life prediction model is developed and estimates of insulation life are presented und er a variety of oil/paper conditions. Systematic measurements of the c oncentration of chemical indicators in transformer oil are used to dem onstrate that furaldehyde and related products can be used to detect h igh rates of paper degradation. Similarly, phenol and related products indicate electrical degradation in phenol-formaldehyde resins.