Breakdown Voltage Characteristics Research Articles

Comparative evaluation by laboratory aging of 15 and 35 kV extruded dielectric cables

It is pointed out that utility engineers encounter a significant problem in discerning the accuracy of claims of superior cable quality and in identifying cables which will provide reliable performance over their anticipated life. The authors, in two independent investigations of 15 and 35 kV cables, have compared the performance of a number of cables made with different compounds by different manufacturers. It is shown that judging cables by their unaged voltage breakdown characteristics alone can be very misleading; that, in the long run, dry-cured cables aged in moist environments rapidly lose their original dielectric strength advantage; that certain ethylene-propylene rubber formulations degrade as fast as cross-linked polyethylene; that the best overall results during aging are obtained with tree-resistant polyethylene insulated cables; and that from a voltage-breakdown point of view water-tree length is more influential than the number of water trees.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Electrical breakdown voltage characteristics of buried silicon nitride layers and their correlation to defects in the nitride layer

An electrical breakdown strength of 3–4 MV/cm was found for buried layers of silicon nitride in silicon-on-insulator (SOI) structures, synthesized by post-implant annealing of high-dose nitrogen-implanted silicon. The lower value of the breakdown field (compared to 3–8 MV/cm for conventionally prepared films) is attributed to defects and the crystalline and silicon-rich nature of the nitride layer as evidenced by X-TEM study.

Characteristics of AC breakdown voltage of high‐voltage ceramic condensers

Characteristics of AC breakdown voltage of high‐voltage ceramic condensers

SF&lt;sub&gt;6&lt;/sub&gt;ガス中の金属粒子汚損直流沿面フラッシオーバに対する沿面形状の影響

The influence of a metallic particle attached to a supporting insulator is remarkable in decreasing the dielectric strength in an SF6 insulated apparatus. To solve this problem, a series of studies has been conducted on a method of improving the particle-initiated breakdown performance. In this paper, dc breakdown voltage characteristics and the breakdown mechanism are investigated under metallic-particle contaminated conditions in SF6 gas by varying the particle condition and the surface shape of the acrylic plate with a rod-plane electrode. The main results show that a rib increases the breakdown voltage by a corona stabilization effect and the elongation of discharge path, but a groove decreases its effect drastically at lower gas pressures. The breakdown voltage at pressures higher than 4 atm may be estimated on the basis of the discharge-maintaining field and the discharge length which depend on the gas pressure and the surface shape.

高電圧セラミックコンデンサの交流破壊電圧特性

高電圧セラミックコンデンサの交流破壊電圧特性

Effect of electrode polarity and additives on the direct breakdown voltage of silicon oil under highly non-uniform fields

The direct breakdown voltage versus gap length (50 to 900 mu m) characteristics were obtained using point-sphere electrodes for degassed silicone oil, oxygen-saturated oil and oil containing varying concentrations (0.005 to 1.0 molar) of 1-methylnaphthalene as additive. The characteristics of degassed and oxygen-saturated methylnaphthalene were also obtained. The shape of the characteristics for both polarities of the point depended on the material of the sphere electrode, the presence or absence of oxygen, and the nature of the liquid itself. In silicon oil the crossover gap length, at which the breakdown voltage is the same for both polarities of the point electrode, was increased greatly by the presence of oxygen, whereas oxygen greatly reduces this gap in hydrocarbon liquids. In both degassed and oxygen-saturated oil the presence of the additive caused a shift in the crossover gap to smaller lengths.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Impulse Voltage Breakdown Characteristics of Teranry Gas Mixtures in A Coaxial Cylinder Gap

Impulse breakdown characteristics for ternary gas mixtures were studied using a coaxial cylinder geometry. The experimental mental pressure ranged from 100 to 600 kPa. The mixtures comprised SF6 with an additive C-C4F8 and various proportions of buffer gases including N2, C02, CO, and dry air. For 50% flashover voltages, mixtures containing CO exhibited highest dielectric strength for pressures up to 500 kPa. The studies also showed that for a coaxial cylinder geometry the breakdown strength is not affected significantly by increasing the amount of the additive gas C-C4F8 but is determined by the total percentage of the electronegative gas component.

Effect of Dry Etching of a Thermal Oxide on Subsequent Growth and Properties of Thin Oxides (≃ 80 Å)

Thin oxides (≃80 Å) have widespread application as the tunnel oxides for floating gate EEPROM devices and as gate dielectrics for submicron MOS devices. Many EEPROM memory cells require a window to be etched by plasma etching into a relatively thick layer of prior to tunnel oxide growth. The high accuracy of defining the tunnel gate area requires sophisticated definition techniques such as stepper lithography and anisotropic plasma etching. This paper describes the effects of anisotropic plasma etching of a 900Å thick thermal oxide on the properties of thin oxides grown subsequently. It is shown that the thin oxide growth rate as well as the oxide breakdown voltage characteristics is affected by the plasma etching conditions.

Breakdown voltage characteristics of thin oxides and their correlation to defects in the oxide as observed by the EBIC technique

Thin oxides are widely used as the tunneling dielectric in floating gate EEPROM devices and as gate dielectric in short-channel MOS devices. The oxides are required to have high breakdown voltage and low defect density for reliable operation of the devices. With the Electron Beam Induced Current (EBIC) technique, defects in the oxide which lead to lower values of the oxide breakdown voltage have been observed.

D.c. breakdown voltage characteristics in supercritical helium: breakdown in nonuniform fields

This Paper describes the results of an experimental study on the d.c. breakdown voltage characteristic of supercritical helium under a non-uniform electric field. The study was carried out to further the development of superconducting magnets cooled by supercritical helium. At a certain density value, ϱ c , a maximum breakdown voltage is observed in the breakdown voltage versus density characteristic. In the case of a negative needle electrode, the breakdown voltage is proportional to the density, ϱ, below ϱ c When ϱ > ϱ c the breakdown voltage becomes almost independent of the density. The ϱ c versus temperature curve, obtained from measurements at different temperatures, agrees well with a pseudo-critical line, which is the phase transition line between the pseudo-gas and pseudo-liquid phase of supercritical helium. The breakdown mechanism of supercritical helium in the pseudo-liquid phase is different from the mechanism in the pseudo-gas phase. The breakdown voltage in the pseudo-liquid region was equal to the breakdown voltage of liquid helium.

Solid: High-voltage, high-gain 300 nm channel-length MOSFETs—I. Simulation

A simple, novel structure for MOSFETs with channels 300–500 nm long is proposed and evaluated by means of two-dimensional numerical analysis. The new device is constructed of a silicide-on-lightly-doped-drain (SOLID) structure. In this structure, the silicide layers assure lower parasitic source/drain resistances. Moreover, distinct segregation phenomena, i.e., formation of a highly concentrated, thin (10 nm) layer at the source/drain-silicide interface, perform an important role in achieving good ohmic contact. With the SOLID structure, most of the N + drain region, which occupies a large portion of the conventional profile-drain structure and is superfluous for lowering high drain field, canbe replaced by an N − region. This results is improved breakdown voltage characteristics with significant mitigation of current gain reduction. The features of the SOLID structure are also compared with those of conventional profile-drain structures, i.e. double diffused drain (DDD) and lightly doped drain (LDD) structures.

The Direct Breakdown Voltage of Silicone Oil Under Uniform Fields

The breakdown voltage versus gap length characteristics were obtained for degassed silicone oil, oil saturated with oxygen, and oil containing varying concentrations of l-methylnaphthalene as additive. Both aluminum and stainless steel electrodes were used. The breakdown voltage versus gap length characteristics for various additive concentrations in degassed oil all pass through a critical gap length at which the breakdown voltage is independent of the additive concentration. For gaps longer than the critical gap the breakdown voltage decreases with increasing additive concentration, whereas for shorter gaps the effect is reversed. For oil saturated with oxygen no such critical gap is present.

An Analysis of Combined Stress Degradation of Rotating Machine Insulation

This paper presents a new method for estimating the life of rotating machine insulation under combined stresses. Since there already exist experimental formulae for each stress degradation (thermal, voltage, and mechanical), the method aims to derive a new formula for multiple stress degradation. The residual breakdown voltage should be a unified measure of degradation. In the method, the amounts of each single stress degradation are converted into that of voltage degradation, with the aid of the unified measure. The total degradation is estimated by summing up these amounts. When it attains the critical value of an insulation, the insulation loses its properties. Voltage endurance curves have been expressed as straight lines on either log-log or semi-log coordinate. Our new method of estimating the life of insulation under combined stresses is applicable to both cases. The interactive effects between stresses can be represented as the change of voltage degradation rate, and the residual breakdown voltage characteristics can be explained with no contradictions to the life characteristics.

Interaction Mechanism between Conductor and Ground Insulation of Stator Windings

In order to get fundamental knowledge in clarifying thermal stress induced in stator windings, the interaction mechanism between the conductor and ground insulation of stator windings under axial load were examined theoretically and experimentally. The stress analysis was carried out with the aid of an equivalent model in which the stator windings were regarded as a composite structure consisting of the conductor and ground insulation bonded to each other by the adhesive. A series of tests were carried out on six different kinds of test bars. The strain distribution on the insulation surface was measured by strain gauges under axial load. The electrical characteristics such as tan and breakdown voltage characteristics were also measured under axial load. The relationship between variations in the electrical characteristics and the occurrence of mechanical damages is discussed. The failure mechanism of the stator windings under axial load is also revealed.

Some Factors Affecting the Direct Breakdown Voltage of Silicone Oil under Nonuniform Fields

The effect of electrode polarity, material, and gap length on the direct breakdown voltage of degassed and oxygen-saturated silicone oil was determined using a point-sphere electrode configuration. The results are compared with those obtained for liquid paraffin under similar test conditions. The shape of the breakdown voltage versus gap length characteristics for both polarities of the point shows a marked dependence on the material of the sphere electrode, as well as on the presence or absence of oxygen. The results indicate a striking difference in the polarity dependence between oxygen-saturated silicone oil and oxygen-saturated liquid paraffin.

Effect of electrode material, oxygen and organic additive on the breakdown strength of mineral oil under nonuniform fields

The direct breakdown voltage against gap length (50 – 1000 μm) characteristics using a point-to-sphere electrode configuration were obtained for degassed mineral oil, oxygen-saturated oil and oil containing varying concentrations (0.005 – 1.0 molar) of 1-methylnaphthalene. Both stainless steel and aluminium were used as the sphere electrode. The shape of the characteristics shows a marked dependence on both the material of the sphere electrode and on the presence or absence of oxygen. The cross-over at point which the breakdown voltage is the same for both polarities of the point electrode was found to be independent of the material of the sphere electrode, but strongly affected by the presence of oxygen and by the additive concentration. The breakdown voltage versus additive concentration characteristics indicate the presence of an optimum concentration at which the breakdown voltage is a maximum. This optimum concentration was found to be independent of the polarity of the point electrode, of the gap length and also independent of the field configuration (uniform or nonuniform).

NMOS voltage breakdown characteristics compared with accelerated life tests and field use data: O. Hallberg. IEEE/Proc. IRPS 28 (1981)

NMOS voltage breakdown characteristics compared with accelerated life tests and field use data: O. Hallberg. IEEE/Proc. IRPS 28 (1981)

Pressure Dependence of Dielectric Breakdown in Liquid Nitrogen

Breakdown voltage characteristics in liquid nitrogen (liq.N2) have been studied in the pressure range between 1 and 15 atm. For constant gap length, the breakdown voltage increases with increasing pressure and saturates at around 10 atm. For shorter pulse width, the increase in breakdown voltage with pressure becomes less remarkable. In a non-uniform field of a plane-needle electrodes system, the breakdown voltage of the negative needle configuration increases remarkably with increasing pressure but that of the positive needle is almost insensitive to the pressure. These results can be interpreted in terms of the suppression of the formation and the development of a gaseous bubble in the breakdown of liq.N2 under high pressure and at short pulse width. The positive streamer seems to play an important role in initiating total breakdown under high pressure and at short pulse width.

Correlations between Nondestructive and Destructive Tests on High-Voltage Coil Insulations for Rotating Miachines

The correlations between results of nondestructive and destructive tests on high-voltage coil insulations for rotating machines were investigated and the following findings were obtained. Breakdown voltage on application of a commercial line voltage (50 Hz) is correlated to the voltage at which a partial discharge bridges the insulation layer. Breakdown voltage on application of a direct voltage is correlated with the discharge magnitude, dielectric constant and dielectric loss tangent corresponding to void discharge in the insulation layer. Breakdown under an impulse waveform voltage is in some respects similar to that under commercial frequency but, because of the short duration of voltage application, it is correlated with the magnitude of electrical resistance, and this correlation is related to the ease with which the bridge phenomenon of discharge in the insulation layer propagates. Thus, the correlation between breakdown voltage and electrical characteristics in nondestructive tests varies with the voltage waveform involved. In tapewound laminated structures, as in micaceous insulatopms, breakdown occurs along the lap of tape, so that characteristic phenomena of the breakdown process for various voltage waveforms combining mutually correlated characteristics, are observed.

Power Frequency and Impulse Voltage Breakdown along Silicone Oil/Xlpe Interface

Power frequency (60 Hz) and Impulse Voltage breakdown characteristics of Silicone Oil (PDMS) with and without cross-linked polyethylene (XLPE) spacers have been studied. The electrode geometries were designed to simulate a high voltage cable termination. In the presence of a spacer, the breakdown stress under 60. Hz voltage remained nearly independent of gap length over the range of gaps studied. The results showed that the risk of discharge inception is low if the tangential stress, along the PDMS/ XLPE interface of a cable termination, does not exceed 1 kV/mm. Under impulse voltage the breakdown values for the liquid gaps with and without the spacers were approximately equal.