Alternating electric field capacitively coupled micro-electroporation

RSC Advances ◽  
2014 ◽  
Vol 4 (97) ◽  
pp. 54603-54613 ◽  
Author(s):  
Arie Meir ◽  
Boris Rubinsky
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Direct Current ◽  
Capacitively Coupled ◽  
High Voltage Direct Current ◽  
Alternating Electric Field ◽  
Biological Solutions

Electroporation of biological solutions is typically performed using galvanically coupled electrodes and the administration of high-voltage, direct current (DC) pulses.

Thermal breakdown in high voltage direct current cable insulations due to space charges

2018 ◽  
Vol 37 (5) ◽  
pp. 1689-1697 ◽  
Author(s):  
Christoph Jörgens ◽  
Markus Clemens
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Direct Current ◽  
Aging Effect ◽  
Radial Symmetry ◽  
Thermal Breakdown ◽  
Content Type ◽  
High Voltage Direct Current ◽  
Space Charges

Purpose In high voltage direct current (HVDC), power cables heat is generated inside the conductor and the insulation during operation. A higher amount of the generated heat in comparison to the dissipated one, results in a possible thermal breakdown. The accumulation of space charges inside the insulation results in an electric field that contributes to the geometric electric field, which comes from the applied voltage. The total electric field decreases in the vicinity of the conductor, while it increases near the sheath, causing a possible change of the breakdown voltage. Design/methodology/approach Here, the thermal breakdown is studied, also incorporating the presence of space charges. For a developed electro-thermal HVDC cable model, at different temperatures, the breakdown voltage is computed through numerical simulations. Findings The simulation results show a dependence of the breakdown voltage on the temperature at the location of the sheath. The results also show only limited influence of the space charges on the breakdown voltage. Research limitations/implications The study is restricted to one-dimensional problems, using radial symmetry of the cable, and does not include any aging or long-term effect of space charges. Such aging effect can locally increase the electric field, resulting in a reduced breakdown voltage. Originality/value A comparison of the breakdown voltage with and without space charges is novel. The chosen approach allows for the first time to assess the influence of space charges and field inversion on the thermal breakdown.

scholarly journals Electric Field and Temperature Simulations of High-Voltage Direct Current Cables Considering the Soil Environment

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4910
Author(s):  
Christoph Jörgens ◽  
Markus Clemens
Keyword(s):  
Temperature Distribution ◽  
Electric Field ◽  
High Voltage ◽  
Direct Current ◽  
Insulation Material ◽  
Soil Environment ◽  
High Voltage Direct Current ◽  
Weakly Coupled ◽  
Surrounding Soil ◽  
Symmetric Temperature

For long distance electric power transport, high-voltage direct current (HVDC) cable systems are a commonly used solution. Space charges accumulate in the HVDC cable insulations due to the applied voltage and the nonlinear electric conductivity of the insulation material. The resulting electric field depends on the material parameters of the surrounding soil environment that may differ locally and have an influence on the temperature distribution in the cable and the environment. To use the radial symmetry of the cable geometry, typical electric field simulations neglect the influence of the surrounding soil, due to different dimensions of the cable and the environment and the resulting high computational effort. Here, the environment and its effect on the resulting electric field is considered and the assumption of a possible radial symmetric temperature within the insulation is analyzed. To reduce the computation time, weakly coupled simulations are performed to compute the temperature and the electric field inside the cable insulation, neglecting insulation losses. The results of a weakly coupled simulation are compared against those of a full transient simulation, considering the insulation losses for two common cable insulations with different maximum operation temperatures. Due to the buried depth of HV cables, an approximately radial symmetric temperature distribution within the insulation is obtained for a single cable and cable pairs when, considering a metallic sheath. Furthermore, the simulations show a temperature increase of the earth–air interface above the buried cable that needs to be considered when computing the cable conductor temperature, using the IEC standards.

scholarly journals Comparative Study of AC and Positive and Negative DC Visual Corona for Sphere-Plane Gaps in Atmospheric Air

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2671 ◽  
Author(s):  
Jordi-Roger Riba ◽  
Andrea Morosini ◽  
Francesca Capelli
Keyword(s):  
Experimental Data ◽  
Field Strength ◽  
Electric Field ◽  
Power Systems ◽  
Electric Field Strength ◽  
High Voltage ◽  
Direct Current ◽  
Complex Nature ◽  
High Voltage Direct Current ◽  
Surface Electric Field

Due to the expansion of high-voltage direct current (HVDC) power systems, manufacturers of high-voltage (HV) hardware for alternating current (ac) applications are focusing their efforts towards the HVDC market. Because of the historical preponderance of ac power systems, such manufacturers have a strong background in ac corona but they need to acquire more knowledge about direct current (dc) corona. Due to the complex nature of corona, experimental data is required to describe its behavior. This work performs an experimental comparative analysis between the inception of ac corona and positive and negative dc corona. First, the sphere-plane air gap is analyzed from experimental data, and the corona inception voltages for different geometries are measured in a high-voltage laboratory. Next, the surface electric field strength is determined from finite element method simulations, since it provides valuable information about corona inception conditions. The experimental data obtained are fitted to an equation based on Peek’s law, which allows determining the equivalence between the visual corona surface electric field strength for ac and dc supply. Finally, additional experimental results performed on substation connectors are presented to further validate the previous results by means of commercial high-voltage hardware. The results presented in this paper could be especially valuable for high-voltage hardware manufacturers, since they allow determining the dc voltage and electric field values at which their ac products can withstand free of corona when operating in dc grids.

scholarly journals IMPACTS OF STATIC ELECTRIC FIELD PRODUCED BY ULTRA-HIGH-VOLTAGE DIRECT-CURRENT TRANSMISSION LINES ON HIPPOCAMPAL PROTEIN EXPRESSION AND MORPHOLOGICAL STRUCTURE IN MICE

2021 ◽  
Author(s):  
JINGTONG YU ◽  
CHUNXIA ZHAO ◽  
XIAOYU GU ◽  
GUOQING DI ◽  
YAQIAN XU
Keyword(s):  
Body Weight ◽  
Electric Field ◽  
Protein Expression ◽  
High Voltage ◽  
Direct Current ◽  
Transmission Lines ◽  
Morphological Structure ◽  
Static Electric Field ◽  
Expression Levels ◽  
High Voltage Direct Current

Static electric field (SEF) from ultra-high-voltage direct-current (UHVDC) transmission lines has the potential to produce neurobiological effects. To explore these effects and elucidate their potential mechanisms, protein expression levels and morphological structure in the hippocampi of mice were investigated after SEF exposure. Mice from the Institute of Cancer Research were exposed to an environmental SEF induced by UHVDC transmission lines with the strength of 9.20–21.85[Formula: see text]kV/m for 35 days. Mouse body weight was measured weekly during the exposure. After the exposure, hippocampal Ca[Formula: see text]/calmodulin-dependent protein kinase II (CaMKII) and calcineurin (CaN) expression levels were assayed by Western blot. Hippocampal pathologic morphology and ultrastructure were observed using light microscopy and transmission electron microscopy, respectively. No significant differences in body weight, CaMKII and CaN expression levels, and hippocampal pathologic morphology were observed between mice in the exposed and the control groups. However, cytoplasmic vacuolization of the hippocampal neurons was observed in the exposed group. Thus, hippocampal neuron ultrastructure damage may be a mechanism of SEF-exposure-induced memory decline in mice.

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