Conduction current pulses in organic insulating liquids under electrical stress

A Short Review of Some of the Factors Affecting the Breakdown Strength of Insulating Oil for Power Transformers

“…Agreeing with [29], it was indicated that the effect of moisture depends entirely on the nature and the amount of other impurities present in the bulk of the liquid [30]. Moreover, above a certain stress level, 300 kV/cm according to [31], particle activity may stop because of either an ejection of impurities from the gap or an adhesion to the electrode surfaces. The influence of impurities also depends on the molecular structure of the liquid [32], as foreign particles can be attracted into the gap and form a bridge distorting the electric field between the electrodes [7].…”

Light Scattering Characteristics of Biological Tissues in Coaxial Ultrasound-Modulated Optical Tomography

“…Several workers (House 1957, Zaky et al 1963 have reported that such pulses could be reduced to a low level of activity by a prolonged stressing of the test gap (stress-conditioning). More recently a number of investigations (Nosseir 1963, Huq and Tropper 1964, Megahed 1965 have been undertaken primarily to study the nature of these pulses and the influence of test conditions on their occurrence and distribution. Although some workers tend to attribute the pulses to the presence in the test liquid of charged microscopic impurity particles which under the influence of an applied field continually oscillate between the electrodes, the evidence is not conclusive.…”

“…Although some workers tend to attribute the pulses to the presence in the test liquid of charged microscopic impurity particles which under the influence of an applied field continually oscillate between the electrodes, the evidence is not conclusive. Sletten and Lewis (1963), Gosling (1960) and Huq and Tropper (1964) studied the behaviour of particles in stressed gaps using an ultramicroscope and concluded that no relation existed between random current pulses and visible particle activity. Huq and Tropper (1964) suggested that pulse activity arises mainly from the formation of bubbles in the bulk liquid.…”

“…Sletten and Lewis (1963), Gosling (1960) and Huq and Tropper (1964) studied the behaviour of particles in stressed gaps using an ultramicroscope and concluded that no relation existed between random current pulses and visible particle activity. Huq and Tropper (1964) suggested that pulse activity arises mainly from the formation of bubbles in the bulk liquid. This is supported by the recent experimental observations of Kao and Calderwood (1965) that, although the conduction currents in a number of dielectric liquids were unaffected by an increase in hydrostatic pressure, the current fluctuations were greatly reduced.…”

Conduction current pulses in transformer oil

“…Although some workers tend to attribute the pulses to the presence in the test liquid of charged microscopic impurity particles which under the influence of an applied field continually oscillate between the electrodes, the evidence is not conclusive. Sletten and Lewis (1963), Gosling (1960) and Huq and Tropper (1964) studied the behaviour of particles in stressed gaps using an ultramicroscope and concluded that no relation existed between random current pulses and visible particle activity. Huq and Tropper (1964) suggested that pulse activity arises mainly from the formation of bubbles in the bulk liquid.…”