The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The ability of vacuum to withstand voltage is a function of many variables and is of utmost importance to the designer of vacuum fault interrupters. These variables are related to the surrounding materials, surface conditions, and shapes, as well as the number of conditioning shots. These variables are usually studied in isolated and ideal conditions; this has lead to conflicting results in the past...
The space charge accumulation properties under dc high stress at various temperatures were investigated in cross-linked polyethylene (XLPE) and XLPE/Carbon composite. We have reported, earlier, that low density polyethylene (LDPE) including inorganic nano-size filler shows a good performance without accumulation of space charge even under very high dc electric field. Since it can be thought that the...
A novel internal electric field enhanced retention model for localized charge trapping memory devices is proposed to explain the reliability degradation. According to the model, the excitation energy level distribution profiles of trapped holes after different P/E cycling stress are demonstrated for the first time.
The dynamic behaviour of water droplets subject to AC electric fields is investigated by experiment and finite element modelling. The motion of a water droplet is considered on the surface of a metallic sphere. To understand the consequences of vibration, the FEA model is introduced to study the dynamics of a single droplet in terms of phase shift between vibration and exciting voltage. Moreover,...
Lifetime estimation of power cables insulations is a very important issue for development of a preventive maintenance policy of cables in order to avoid their premature breakdown and interruption of power supply to consumers. In this paper a lifetime estimation method of a low density polyethylene insulated cable is presented. For this purpose, accelerated tests on model cable samples immersed in...
We use a lateral scaling methodology based on the bond-dispersion model to develop a generalized hot carrier degradation model for cascoded NMOS transistors in power management applications. Spatial profiling of interface traps (NIT) based on charge pumping measurements is used to identify damage regions responsible for VT and IDLIN degradation and to explain their time dependencies.
It was described the size optimizations to the stress cones as which were key structre parts in the 27.5/48 kV XLPE cable heat/cold shrinkable combinated terminations, aslo included the effection performance to the elctric field strength by adjusted the radius to the innnerside bend surface of the stress cones. The result were indicated that the optimization could be applied for the designing and...
Poly-Si TFTs with vacuum cavities underneath the poly-Si gate edges (quasi-T gate poly-Si TFTs) were successfully realized by partially wet etching the gate oxide and encapsulating in a vacuum. Because of the vacuum cavity not only as an offset region to reduce the abnormal leakage current in the OFF-state but also as a field-induced drain (FID) to sustain the on-current in the ON-state, the electrical...
This work studies the effect of protrusions and voids in DC cables taking into account the effect of conductivity and field distribution in DC cables. A 2D-FE model has been developed in order to verify theoretical analysis, revealing good agreement with analytical formulas.
In industry, there have been several documented failures on the lower (oil side) region of high voltage power transformer bushings. In these cases, the failure mode was considered to be due to localised discharges, as a result of accumulated surface contaminants. Given failure is often catastrophic, it is therefore difficult to establish the exact point of failure. In this paper, a numerical model...
The Fowler-Nordheim (FN) stress on PMOSFET cause Idsat decrease and Vth increase. In this work, we have investigated FN stress induced device degradation mechanisms in PMOSFETs with different gate length and oxide thickness. We describe a quantitative relationship between Idsat, Idlin and Vth change under FN stress condition.
Oil-immersed insulating material has an anisotropic and nonlinear conductivity, so the direct current (dc) electric field calculation should take these factors into consideration. In this paper, a new calculating method based on ANSYS secondary development technology is proposed. Then, the nonlinear and anisotropic dc electric field is calculated, considering electrical stress and temperature impact...
The Pulse Width Modulated (PWM) voltage waveforms produce complex overvoltages that stress the insulation of cables and rotating machines more severely than normal sinusoidal voltage. The overvoltages have a form of fast switching pulses with very short rise time, composed of repetitive sequences. Such conditions have influence on inception and activity of partial discharges (PD) and space charge...
As one promising material in the family of soft materials, dielectric elastomer can potentially function as transducers in cameras, robots, valves, pumps, energy harvesters and so on due to its capability of large deformation, fast response etc‥ The dielectric elastomer transducers are based on the deformation of a soft polymer membrane contracting in thickness and expanding in area, which is induced...
Hot-carrier-injection (HCI) effects are studied in n-channel rugged LDMOS transistors in high current-voltage biases, by monitoring the linear and saturation regimes. Experimental data reveal that the degradation effects responsible for the HCI parameter drifts are mainly localized in the channel and in the drift region close to the drain. The temperature dependence of the HCI degradation is analyzed...
As a purpose of developing micro-electric machines, transient behaviors of a nematic liquid crystal between two parallel plates are simulated with various parameters such as applied voltage, gap between the two plates, twist and tilt angles. When the twist anchoring angle is 0 degree, the induced velocity profile is anti-symmetric S-shaped profile. The velocity profile is symmetric for the case that...
From the aspect of design and operation, cables and cable accessories are still very actual. Technological developments and the increasing need for electricity cause wider everyday cable termination applications. To ensure reliable performance over the cable system lifetime, design concepts, based on numerical calculations, must be correct. An Equivalent Electrodes Method/Boundary Elements Method-hybrid...
The biological effect of electric fields on protein function and structure is a topic of increasing interest over the past few decades. With the proliferation of microwave devices the exposure to microwave radiation has become part of everyday life. The ubiquity of devices emitting electromagnetic radiation has highlighted concerns about the potential health effects. This work explores the dynamics...
Static control of cylindrical shells is investigated in this study. The function of piezoelectric stresses is defined first. The piezoelectric stress contains two parts: one is caused by external electric fields and the other is induced by the strain of the piezoelectric film itself. The internal forces, moments and displacements of shell under external forces are derived using the classical elastic...
A finite crack is studied in two-dimensional (2D) infinite piezoelectric medium with arbitrary electric poling direction in the present paper. A self-consistent method is employed to obtain the real crack opening and the electric field in the crack cavity under combined mechanical-electric loadings. The influences of poling direction and electric boundary conditions on fracture behaviors are investigated,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.