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The non-breakdown and breakdown streamers in paraffinic model oil were investigated under negative "step" voltages. Experiments were performed with the point-plane gap of 8 cm and voltage up to 540 kV. Streamer behaviors were observed with shape, stopping length, velocity, current and light emission pulses. Carbon particles markedly reduce inception and breakdown voltages of streamers, while...
The energy demand of the whole world is dominated by petroleum products for centuries in the field of critical application like electricity. The application of mineral oil in power system equipment like transformer is potentially hazardous to environment. The exploitation of petroleum oil is running out of demand and in the near future, oil scarcity exists. This work focuses in identifying alternate...
To obtain relationship between concentration of SF6 decomposed characteristic components (or their concentration ratio) during the formation process and partial discharge qualities and pulse repetition rate, this paper used needle-plate electrode to simulate outthrust insulation fault and conducted a serial of experiments. First, the SF6 decomposition characteristic under different PD strengths is...
There has been a typographical error in equation (11) p.75, of the recently published paper M. Levesque, et. al. [ibid., Vol. 20, pp. 71-81, 2013]. A parenthesis has been wrongly placed, which has changed completely the mathematical expression. The corrected equation (11) is provided.
In artificial icing tests, three test methods are frequently used for evaluating the electrical characteristic of ice-covered insulator strings, they are: average flashover voltage method (AM), 50% withstand voltage method (WM) and minimum flashover voltage method (MM). Based on measurements of DC flashover characteristics of ice-covered porcelain and glass suspension insulators in an artificial climate...
Partial discharge (PD) has been identified as one the main root causes of stator winding failures in low voltage (LV) random wound AC motors fed by PWM inverters. To ensure that PWM inverter-fed motors (type I) are PD-free under impulse excitation, the test procedure for acceptance testing of the stator insulation system was developed (IEC TS 60034-18-41). Although many successful cases of applying...
Pollution distributes irregularly on the surfaces of traction power supply system insulators as high-speed trains pass through pollution aerosols. This affects the flashover characters. Insulator polluting characteristics were studied in a wind tunnel at speeds up to 100 m/s. The gas-solid aerosol flow around insulator was analyzed and a pollution accumulation model was established after analyzing...
When driving capacitive loads, pulses with steep falling edges are difficult to obtain using conventional pulsed power modulators, which also makes them unsuitable for operating at higher frequencies. In this paper, a repetitive high voltage pulse adder is described, which can generate nearly rectangular pulses even with capacitive loads. This pulse adder is based on solid-state switches, and each...
The paper reports on generation of controllable underwater shock waves through the use of a magnetic pulsed compression circuit as the power source of underwater spark discharge to aid in improving accuracy and safety in medical applications. In the present work, we were able to widely change the peak pulsed voltages by the magnetic pulsed compression circuit. Sensitivity of underwater shock wave...
In nanosecond pulsed electroporation of biological cells nanosecond duration pulses with high frequency spectral content are applied to the cell. We show that accurate modeling of the electroporation process on these time scales requires considering the effect of the dielectric dispersion on the electric potential across the membrane. We describe the dielectric relaxation of the membrane as dispersion...
A numerical model, usually employed to analyze the electroporation phenomenon in eukaryotic cells exposed to high voltage electric pulses with duration in the ms to ??s time scale, is extended to investigate the electroporation onset and dynamics induced by nanosecond pulsed electric fields (nsPEFs). The model allows to track the primary events and dynamics of the electroporation process on a time...
We are pleased to present this fourth special issue of the IEEE Transactions on Dielectrics and Electrical Insulation (TDEI) on Power Modulators and Repetitive Pulsed Power. A call for manuscripts for this volume was issued in TDEI and in conjunction with the 2012 IEEE International Power Modulator and High Voltage Conference (IPMHVC), which was held in San Diego, CA, USA during June 3-7, 2012. This...
During the working period of the ion source of a Neutral Beam Injector (NBI) for plasma heating, the temperature of its transmission line inserted in its snubber rises rapidly. This is because the heating current of the filament and arc reaches over 10 kA for over 100 s, which accumulates large amounts of energy on the line. Rapidly ageing of the wire insulation will occur as the temperature rises...
Bioelectrics has attracted much attention. Inducing apoptosis in malignant cells using subnanosecond pulses has previously been investigated; these results have encouraged the authors to develop a burst electromagnetic wave focusing system for cancer treatment through the induction of apoptosis to cells. Burst electromagnetic waves are characterized by a high-frequency and narrow band signal over...
This paper explores the feasibility of a new triggering technology that is based on reversed-LTD (linear transformer driver) principle. The triggering technology which is named as LTD-trigger has a similar structure to LTD device, but it operates reversely relative to LTD. The LTD-trigger is small size and can obtain multiple trigger pulsed voltages flexible with one single primary high-voltage pulsed...
The High Voltage Convertor Modulators are used to power the RF klystrons used throughout the linear accelerator at the Spallation Neutron Source. The output voltage of the modulator has significant voltage droop and ripple which, combined with low level RF system limitations, affect performance and stability of the accelerator cavities. In conjunction with the progress in the development of the new...
This study proposes a novel method of partial discharge (PD) electrical signal analysis based on the Hilbert–Huang transform (HHT) with fractal feature enhancement. Firstly, this study establishes four defect types of 15 kV gas-insulated switchgear (GIS) and uses a commercial high-frequency current transformer (HFCT) to measure the electrical signals caused by the PD phenomenon. Second, the authors...
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