The effect of organic additives on the breakdown and gassing properties of mineral oils

Abstract

The effect of organic additive content on the direct voltage breakdown strength of degassed transformer oil and liquid paraffin is reported for a wide range of concentration of additives known to be effective gassing inhibitors. Their effect on the breakdown strength of oils saturated with hydrogen, nitrogen and oxygen is also reported. Measurements of the gassing properties of the oils were carried out for the same extended range of additive concentrations. The observed breakdown and gassing versus concentration characteristics indicate the presence of maximum and minimum points at concentrations which are independent of the matrix liquid and of dissolved gas and gas phase. There is a remarkable degree of correlation between the breakdown and the gassing properties of the liquids tested. This and other relevant observations indicate that gas generation is an intrinsic part of the breakdown process and strongly support the bubble theory of breakdown. This forms the basis for the discussion of the results.

The Effect of Electronic Scavenger Additives on the AC Dielectric Strength of Transformer Mineral Oil

“…Contrary to Zaky and Hawley [6], Mathes and Rouse [8] reported that the addition of a small concentration of poly-aromatic compounds significantly reduces the dielectric strength of naphthenic oil in a point-to-sphere electrode arrangement under impulse voltage. This reduction in the breakdown voltage has been attributed to the streamer development and especially to the increase in the velocity of the streamers' propagation: the faster the streamer, the lower the dielectric strength.…”

“…Thus, it has been observed that several specific nanoparticles such as Fe 3 O 4 significantly enhance the dielectric strength of mineral oils [1][2][3][4][5]. Nevertheless, the results reported in the literature on the influence of aromatic additives on the breakdown voltage of insulating oils are contradictory [6].…”

“…Thus, Zaky and Hawley [6] reported that weak concentrations of aromatic additives enhance the breakdown voltage of insulating oils and that there is an optimum concentration of additives that results in a maximum increase of the breakdown strength. Evangelou et al [7] reported that the breakdown voltage varies with the additive concentration in a complex manner.…”

Dielectric Strength Improvement of Natural Ester Insulation Oil via Mixed Antioxidants: Taguchi Approach

“…The PDIV is defined as the voltage in which the partial discharge (PD) is initiated above the threshold of 20 pC. Zaky et al [22] also attributed this behaviour to the addition of additives containing aromatic compounds into the insulation oil.…”

Influence of electronic scavenger additives on AC breakdown voltage of synthetic ester

“…However, another area of research which has been somewhat neglected and which could present another interesting line of research is that of molecular additives. Among the investigations dealing with these kinds of additives and their influence on the breakdown voltage (BDV) of insulating oils, the aromatic compounds [1]. Unfortunately, the reported results are contradictory [1][2][3][4].…”