Experimental investigation of temperature effect on corrosive sulfur formation in transformers

This paper presents experimental findings of the effect of temperature on corrosive sulfur formation in transformers. To conduct the experimental study, new transformer oil was randomly selected and heated at 40, 60, 80, 120, and 150 °C temperature for 72 hours each along with copper strips wrapped with insulation paper and immersed in oil in accordance with IEC-62535 standard test covered conductor deposition (CCD). The oil, copper strips, and the insulation paper samples were evaluated using gas chromatography-sulfur chemiluminescence detector (GC-SCD), X-ray fluorescence spectroscopy (XRF), inductively coupled plasma optical emission spectrometry (ICP), and scanning electron microscopy (SEM) tests after 72 hours exposure at each temperature. The values so obtained, were analyzed and effect of temperature on various parameters was studied individually and as well as collectively. It was found that temperature plays an important role on corrosive sulfur formation process inside the transformers and hence the temperature of the oil should be kept within the allowed operating ranges for avoiding unforeseen failures.