Partial discharge behaviour of an alternative insulating liquid compared to mineral oil

Alternative Fluids – with a Particular Emphasis on Vegetable Oils – as Replacements of Transformer Oil: A Concise Review

“…The authors seemed to reluctantly propose both vegetable oils as replacements of the transformer oil on the condition of further purification. Authors in [48] seem to agree with the results published before, where mineral oil was compared with vegetable oil and synthetic ester oil in the presence of pressboard [49]. In [49], Partial Discharge (PD) levels were found to be higher in both alternative oils than in mineral oil.…”

“…Authors in [48] seem to agree with the results published before, where mineral oil was compared with vegetable oil and synthetic ester oil in the presence of pressboard [49]. In [49], Partial Discharge (PD) levels were found to be higher in both alternative oils than in mineral oil. Although no specific reason was given for such differences in the PD level, [49] was an effort to investigate solid/liquid insulation as is used in transformer windings.…”

“…It should be noted, however, regarding PD activity, both palm oil and corn oil showed a lower activity than mineral oil with a rod-plane electrode arrangement at 25 kV, especially after thermal aging of 30 and 45 days [57]. The PD results of [57] are in disagreement with the results of [49].…”

“…Danikas & Sarathi: Alternative Fluids -with a Particular Emphasis on Vegetable Oils -as … offered intermediate properties whereas corn and sunflower oil oxidized appreciably after aging. Authors in [55] reported that partial discharge magnitudes of Palm Fatty Acid Ester (PFAE) are slightly lower than those of petroleum-based mineral oil during the aging time, which somehow contradicts the findings in [49]. In [56], the authors investigated the problem of dielectric strength of mineral oil, corn oil, sunflower oil, and rapeseed oil from another viewpoint, namely that of statistical analysis.…”

“…In [49], Partial Discharge (PD) levels were found to be higher in both alternative oils than in mineral oil. Although no specific reason was given for such differences in the PD level, [49] was an effort to investigate solid/liquid insulation as is used in transformer windings. Although there was some skepticism, as reported above, there were other publications that suggested the use of vegetable oils, since these presented a dielectric strength comparable to that of mineral oil and the saturated fatty acid content in such oils retarded the deterioration of the insulating fluid in hightemperature environments or long-term storage conditions.…”