High Voltage Electric Research Articles

A study of high transient voltage unit realization uncertainty

The problem of metrological support of high-voltage pulse generators with subnanosecond rise time, as well as pulse voltage dividers used in power engineering, aviation and rocket-space industries, has been solved. As a result of the modernization of the State primary special standard of transient electric and magnetic field strengths units with a pulse rise time in the range of 0.1–10.0 ns GET 148-2013, a mode of realization a unit of high transient electric voltage with a minimum pulse rise time of 100 ps was implemented. Uncertainties of high transient electric voltage unit realization obtained by numerical simulations using the Monte Carlo method, as well as in accordance with the Guide to the Expression of Uncertainty of Measurement (GUM), are estimated. Also, the error of a unit realization was estimated in accordance with GOST 8.381-2009 “GSI. Standards. Methods to Express Accuracy”.

Investigation of Power Supply to Subsea Loads from High Voltage Electric Source Using Modular Direct Current Scheme

Subsea power converters have been identified in recent researches as a potential means of supplying power to subsea loads and this technology has been seen as a means to reduce the reliance on offshore platforms. This study analyses all electric subsea high power system for power generation and transmission in the offshore oil and gas industry for sustainable subsea development. In order to accomplish the analysis of power generation and transmission to subsea loads, the MAT lab SIMULINK software was employed to ascertain losses arising from the transmission of power to subsea systems. Data from Agbara and Akpo fields, all located in Nigeria, were analysed using the MSDC model as an alternative power source for power generation and transmission to all subsea loads. When the voltage loss between a step out distance at 30 km and 200 km was compared for the Akpo oil field, the plots indicate a significant loss in voltage. The RMS value of voltage loss increased from 0.8874 at a step out distance 30 km to 0.9449 for 200 km.

The Study of Thawing Characteristics and Mechanism of Frozen Beef in High Voltage Electric Field

The aim is to comprehensively and further explore the thawing characteristics and mechanism of frozen beef in high voltage electric field (HVEF). In this paper, the frozen beef was thawed under blocking ionic wind and changing voltage, electrode distance in the high voltage electric field system. The thawing characteristics, quality parameters and microstructure of beef during thawing were measured. The results showed that compared with the control, high voltage electric field could significantly shorten the thawing time of beef. During the thawing process, the influence of the high voltage electric field in the beef center temperature range from -5 °C to 0 °C on the thawing characteristics is larger than the control. Electrode distance and voltage have significant influence on color, loss rate and quality parameters. The experimental results of blocking ionic wind showed that ionic wind and non-uniform electric field have different effects on the characteristic parameters, quality parameters and microstructure of beef. Both the ionic wind and non-uniform electric field played a significant role in thawing process. This study provides theoretical basis and practical guidance for further understanding of the parameter characteristics and thawing mechanism of high voltage electric field thawing technology.

Dampak Korona pada SUTET 500 kV Terhadap Radio Interference

Corona can occur in SUTET because SUTET carries a high enough electric current and voltage, this causes excessive electrical pressure that is not proportional to the breakdown strength of the air around the conductor so that there will be a phenomenon where the electric field will collide with free electrons in the air and will form ionisations in the form of new ions and electrons. This process will continue as long as there are currents and voltages on the extra-high-voltage network. This certainly will affect the surrounding environment through which SUTET is included, among others, interference with radio waves (Radio Interference). The addition of the number of sub conductors is considered more effective in reducing corona losses and radio interference in each wicket than increasing the distance of the conductor to the ground. The impact of corona on a 500 kV double-channel SUTET on radio interference in the Greater Jakarta area is still within reasonable limits because it is still below the IEEE standard of 40 dB.

Prognostic factor analysis of irreversible electroporation for locally advanced pancreatic cancer – A multi-institutional clinical study in Asia

IntroductionIrreversible electroporation (IRE) is a modality that utilizes high electric voltage to cause cell apoptosis. IRE has been used to treat locally advanced pancreatic cancer (LAPC). However, studies of IRE via surgical approaches for LAPC are limited. This study aims to analyse the outcomes and related prognostic factors of IRE for Asian patients with LAPC. Materials and methodsFrom 2012 to 2017, this prospective trial for using IRE through surgical approaches for LAPC was conducted in 11 medical centres in Asia. All related and treatment outcomes were analysed from a prospective database. ResultsSeventy-four patients were enrolled. Thirty complications occurred in thirteen (17.6%) patients without mortality. The electrode placement direction (anteroposterior vs. craniocaudal, HR = 14.2, p < 0.01) and gastrointestinal invasion (HR = 15.7, p < 0.01) were significant factors for complications. The progression-free survival (PFS) rate in one year, three years, and five years were 69.1%, 48.7%, and 28.8%, and the overall survival (OS) rate in one year, three years, and five years were 97.2%, 53%, and 31.2%. In univariate analysis, the chemotherapy regimen, local tumour recurrence, axial tumour length, tumour volume, and serum carbohydrate antigen 19-9 levels were all significantly associated with PFS and OS. In multivariate analysis, the chemotherapy regimen was the only significant factor associated with PFS and OS. TS-1 (Tegafur, gimeracil, and oteracil) group has superior survival outcome than gemcitabine group. ConclusionThis study showed that combined induction chemotherapy and surgical IRE for LAPC is safe. For well-selected patients, IRE can achieve encouraging survival outcomes.

Clinical characteristics and repair effect of 136 patients with electric burns of upper limb

Objective: To analyze clinical characteristics and wound repair methods and effects of patients with upper limb electric burns. Methods: Medical records of 136 patients with upper limb electric burn who met the inclusion criteria and hospitalized in our unit from January 2015 to March 2019 were retrospectively analyzed. Proportion in patients with electric burns in the same period, gender, age, admission time, categories, injury causes, injury voltage, burn area and depth of upper limb, simultaneous injury of both upper limbs, and early wound treatment measure of patients with upper limb electric burn were recorded. The main repair methods of each affected limb were classified and recorded. The overall efficacy of the patients was recorded, including postoperative wound complications and healing condition. The patients repaired with distal pedicled flaps and those with free flaps were followed up for 3 to 6 months. The survival rate of flaps were recorded, the function of affected limbs after operation was evaluated, and the satisfaction degree of patients was investigated by Curative Effect Score Table. The amputation rate, age, and burn area of upper limbs of patients caused by high-voltage and low-voltage electricity were compared. Data were processed with Wilcoxon rank sum test, chi-square test, or Fisher's exact probability test. Results: (1) The number of upper limb electric burn patients accounted for 88.3% of 154 patients with electric burns hospitalized in the same period, including 117 males and 19 females, aged 1 year and 2 months to 72 years [(34±18) years], admitted 1 h to 48 d after injury, including 51 electricians, 32 rural migrant workers, 31 students and preschool children, and 22 patients belonging to other categories. Patients of the first two categories were mainly injured by work accidents, and those of the latter two categories mainly suffered from touching power source or power leakage. Among all the patients, 75 cases were injured by high-voltage electric burn, and 61 cases were injured by low-voltage electric burn, with burn area of upper limb from 0.2% to 16.0% [2% (1%, 5%)] total body surface area (TBSA) and area of wounds deep to bone from 0.2% to 15.0% [2% (1%, 5%)] TBSA. Two upper limbs in 54 cases were simultaneously injured, accounting for 39.7%. Early fasciotomy was performed for 73 limbs. (2) Thirteen affected limbs were treated with dressing change, 2 affected limbs were sutured directly after debridement, 56 affected limbs were repaired by skin grafting, 12 affected limbs were repaired by local flap, 45 affected limbs were repaired by distal pedicled flap, 22 affected limbs were repaired by free flap, and 40 affected limbs were amputated (accounting for 21.1%). (3) One case died of pulmonary infection, sepsis, and multiple organ failure after operation, and the rest patients were all cured. One case with avulsion of abdominal flap was repaired by skin grafting after dressing change. The anterolateral thigh flap in one case necrotized after transplantation, which was replaced by pedicled abdominal flap. Seven cases had small erosion on the pedicle or margin after transplantation of abdominal flap and were healed by dressing change. Six cases had local bruising at the distal end after transplantation of abdominal flap and were healed after conservative treatment such as hyperbaric oxygen. The other flaps survived well. (4) The survival rate of distal pedicled flap grafting was 97.8% (44/45), which was close to that of free flap grafting (95.5%, 21/22, P>0.05). The function recovery of affected limb after free flap grafting was better than that of distal pedicled flap grafting (Z=-3.054, P<0.01), but their satisfaction degree of patients was similar (Z=-0.474, P>0.05). (5) Patients with high-voltage electric burn had higher amputation rate, older age, and larger upper limb burn area than those with low-voltage electric burn (χ(2)=4.743, Z=-2.801, -6.469, P<0.05 or P<0.01). Conclusions: Upper extremity electric burn often occurs in children, electricians, and rural migrant workers with high rate of amputation. Teachers and parents should strengthen safety education for children and manage power source of life well. Workers should improve safety awareness and operate standardly. Fasciotomy for relaxation should be performed for electric burn wound as soon as possible, and flap grafting can effectively repair wound after early debridement. The function recovery of affected upper limb repaired with free flap grafting is better.

In-situ hybridization of graphene sheets onto polyaniline nanofiber arrays grown on the surface of carbon cloth under high electric voltage field for high–performance flexible supercapacitor

Two kinds of free–standing flexible hybrid electrode materials were fabricated through in situ hybridization of graphene oxides (GOs) onto polyaniline (PANI) nanofiber arrays grown on the surface of carbon cloth under high voltage electric field. The GOs introduced to the arrays could act as the growth sites or the top layer on the PANI arrays, depending on the spraying order of the GO before and after aniline. Great improvement in charge storage ability of PANI nanofibers could be achieved especially by using the GO as the substrate for the growth of the arrays. The PANI/GO/CC electrode showed a maximum areal capacitance of 1122.8 mF cm−2 at the scan rate of 5 mV s−1. Assembled with these electrodes, the all–solid–state symmetric supercapacitor could deliver a maximum energy density of 46.6 μWh cm−2 at a power density of 498.9 μW cm−2 with high capacitance retention of 94.1% and mechanical flexibility. The excellent capacitive performances could be ascribed to unique structural advantages of PANI nanofiber array enhanced by synergetic effect between PANI and graphene sheets. Such in situ hybridization could provide a facile and scalable route for fabricating high–performance free–standing flexible electrode materials for foldable and wearable devices.

Multiple Harmonic Source Location Using the Least Median of Squares Method with the Presence of Outliers in High Voltage Electric Power Systems

A static multipoint method to locate harmonic sources in high-voltage electric power systems based on the least median of squares approach is presented. Because of statistical robustness, the least median of squares method is used, even in the presence of multiple erroneous measurements. The special features of the method are described in this article. IEEE-30 bus test system with three harmonic sources and uniformly distributed erroneous measurements is solved with the least median of squares, Heydt’s and Euclidean norm methods. Several harmonic sources are correctly located with the least median of squares method. The least median of squares approach estimated harmonic bus voltages and currents is close to the actual values. With Heydt’s and the Euclidean norm methods the harmonic sources cannot be located in the presence of uniformly distributed erroneous measurements.

A Case Report of Survival of Young Adult Following Asystole after Sustaining High Voltage Electric Current

A Case Report of Survival of Young Adult Following Asystole after Sustaining High Voltage Electric Current

Output Current Control System of a High Voltage Electric Pulse Generator for Plasma Excitation

A control and pulse discharge current limiting system integrated into an AC/DC converter and pulse modulator of a high voltage pulse generator have been developed. The peculiarity of such system\textquotesingle s operation is the stabilization of the power supplied to the discharge and the correction of the width of output electric pulses towards decrease upon reaching the specified pulsed current amplitude value. The system enables the pulse generator to work in the modes close to the ``short circuited load'' mode. In this case the driving module of a composite IGBT key performs the correction of the working pulse width and blocks the pulse generator operation if needed. The suggested circuit design solutions allow using the generator in a wide range of electric plasma-forming parameters' modes and working with various types of vacuum gas discharge systems.

Ejection of cell laden RPMI-1640 culture medium by Electrohydrodynamic method.

Sample deposition based on micro-droplet ejection has broad application prospects in the field of biomedicine. Ejection of RPMI-1640 medium (with and without cells) is investigated experimentally using a home-build electrohydrodynamic (EHD) ejection system, consisting of a liquid supplier and a nozzle, a high voltage source, a droplet collector, and a high speed photography module. High electric voltage is applied between the nozzle and the droplet collector. The liquid surface is electrically charged and the ejection takes place when electric force overcomes the surface tension. The ejection process is studied by using high speed photography and image processing. At low voltage, a stable ejection state is established with ejection frequency ranging from a few to a few tens of Hertz. At high voltage, another stable ejection state is reached with ejection frequency as high as 1300Hz. At the transition voltage range, the ejection exhibits a periodic behaviour. During each cycle, the meniscus rapidly oscillates with gradually increased amplitude, and with several non-uniform droplets ejected at the final stage of the cycle. Human peripheral blood mononuclear cells, after ejection, shows survival rates higher than 79%, manifesting EHD ejection as a promising technique for cell printing.

Performance of Cross-linked Polyethylene Insulated Cable based on Detection of High Voltage Electric Field

High voltage direct current transmission has been&nbsp;widely used in long-distance&nbsp;power&nbsp;transmission because of its advantages such as low loss and large throughput. The safety of cable is very important&nbsp;in the long-distance transmission process. Cross-linked polyethylene insulated cable has the advantages of simple manufacture, good heat resistance and easy installation; therefore&nbsp;it has been&nbsp;widely used in long-distance power transmission. In this study, conductance, dielectric and voltage withstanding&nbsp;performance&nbsp;of the insulating layers of cross-linked polyethylene cables with working voltage of 220 kV which was never used and has been used for 2, 4, 6 and 8 years were&nbsp;tested&nbsp;by various evaluation methods.&nbsp;The conductivity of the insulating layers was affected by temperature&nbsp;only&nbsp;under&nbsp;high and low electric field intensities and was affected by temperature and electric field strength under middle electric field intensity. Dielectric loss factor&nbsp;could reflect&nbsp;dielectric properties&nbsp;of materials; the larger the dielectric loss factor, the poorer the performance. The dielectric loss factor decreased&nbsp;with the increase of applied electric field frequency&nbsp;and&nbsp;increased&nbsp;with the increase of service years. Breakdown electric field strength&nbsp;could&nbsp;reflect&nbsp;voltage resistance&nbsp;of materials; the larger the breakdown electric field strength, the better the performance. The breakdown electric field strength was inversely proportional to the service years of the insulating layer, and the decrease amplitude&nbsp;increased&nbsp;significantly when&nbsp;the service time&nbsp;exceeded&nbsp;2 years. In summary, cross-linked polyethylene insulated&nbsp;material satisfies the safety requirement of high voltage direct current transmission and can be used for manufacturing long-distance transmission cables.

A New Techniques to Calculate the Efficiency of Electric High Voltage Network in Basra

The complexity of electrical power system that need to provide electricity to many customers under different requirement with high efficiency. For this reason, its imperative to find a modern technology that can be implemented to obtain reliable electrical power network. In this paper is a new technique have been proposed based on the load flow direction from generation station to substations. Keep track of route method was implemented to determines the path of the load flow and give minimum disconnected. Matlab environment software was implemented later to discover the weaknesses point and calculate the efficiency of the electric power network.

Investigation on a soft grasping gripper based on dielectric elastomer actuators

A novel soft grasping gripper which is based on dielectric elastomer actuators (DEAs) is presented in this paper. The gripper presents a self-contained and inherently soft approach for grasping objects. A single actuator membrane based on an acrylic elastomer inflates upon application of high electrical voltages. The actuation deformation of the membrane results in a frictional grasp of an underlying object from multiple angles simultaneously. The gripper comprises of a pressurized chamber sealed by the cylindrical DEA and relies on the friction force between the DEA membrane and the object. Mathematical analyses are carried out to simulate the actuation deformation of the DEA membrane and to estimate the grasping force with 3 cylindrical objects of different sizes. Experimental results validate the analytical analyses and show up to around 20% of membrane actuation deformation and 2N of grasping forces.

Experimentally and Numerically Analyzed Piezoelectric Characteristics of PZT Ceramics

The electric generation characteristics of the PZT piezoelectric ceramics were examined experimentally and numerically. In this case, cyclic bending loading was applied to the PZT ceramics: bulk and thin-film membrane. Electric voltage increased with increasing the strain value. There was a sharp initial increase in positive voltage for the PZT ceramics as bending load was applied. Following this initial increase stage, a rapid fall to zero occurred. The reduction rate of the positive voltage was changed depending on the rigidly of the PZT ceramic: the higher the reduction rate, the higher the rigid of the ceramic. The electrical voltage from the circular membrane PZT ceramic during cyclic loading showed the higher level compared to that for the bulk one, in which the flexibility of the PZT ceramic was significant factor to obtain the high electric voltage. The variation of the electric voltages was estimated numerically, which was relatively in good agreement with the experimental one.

Performance of Cross-Linked Polyethylene Insulated Cable Based on Detection of High Voltage Electric Field

High voltage direct current transmission has been widely used in long-distance power transmission because of its advantages such as low loss and large throughput. The safety of cable is very important in the long-distance transmission process. Cross-linked polyethylene insulated cable has the advantages of simple manufacture, good heat resistance and easy installation; therefore it has been widely used in long-distance power transmission. In this study, conductance, dielectric and voltage withstanding performance of the insulating layers of cross-linked polyethylene cables with working voltage of 220 kV which was never used and has been used for 2, 4, 6 and 8 years were tested by various evaluation methods. The conductivity of the insulating layers was affected by temperature only under high and low electric field intensities and was affected by temperature and electric field strength under middle electric field intensity. Dielectric loss factor could reflect dielectric properties of materials; the larger the dielectric loss factor, the poorer the performance. The dielectric loss factor decreased with the increase of applied electric field frequency and increased with the increase of service years. Breakdown electric field strength could reflect voltage resistance of materials; the larger the breakdown electric field strength, the better the performance. The breakdown electric field strength was inversely proportional to the service years of the insulating layer, and the decrease amplitude increased significantly when the service time exceeded 2 years. In summary, cross-linked polyethylene insulated material satisfies the safety requirement of high voltage direct current transmission and can be used for manufacturing long-distance transmission cables.

APPLICATION OF THERMOMIGRATION FOR TECHNOLOGY OF POWERFUL SEMICONDUCTORS APPLIANCES

Contex. The conducted researches allow to improve technological processes of manufacture of semiconductor devices and control of their quality. Objective is to investigate the relief of silicon etching in the area of p + -Si isolation and using of Al-thermigration processes for further develop and improve technology of the power devises. The task of the work is to optimize these technology.Method. The object of the study was the technological features of the processes of forming structures on different routes, differing in the manner of carrying out processes of annealing structures and processes of thermomigration Al. The influence of the annealing time on the features of the microrelief of etching grooves in the region of thermomigration has been studied. Results. The causes of change of breakdown voltage of vertical p-n- junctions formed by thermomigration vs post-migration annealing time and thermomigration process optimization are discussed. On these samples is observed minimal microrelief of the groove etching of various types of conductivity silicon in the area under the insulation of the crystals. Such a minimal microrelief determines the minimum of residual mechanical stresses. The control of changes in the kinetics of etching layers of monocrystalline silicon in the field of thermal migration of aluminum impurities helps in determining the modes of technology for the formation of semiconductor structures with high breakdown electrical voltages. At the same time, two conditions are fulfilled: the first one is the excess of the lateral length of aluminum diffusion over the lateral length of the region of mechanical stresses along the perimeter of the thermo-migration region; and the second, it is a reduction and stabilization of changes in the rate of etching of the thermo-migration layers by minimizing the elasticmechanical, deformation component of the activation energy of the etching process of p+-Si. It is shown that in the manufacture of chips of larger power devices with a larger area and a reverse voltage of up to 2000 V, the optimal variant is the route variant, when the processes of impounding impurities of deep active layers are first carried out, then the processes of thermomigration during the formation of insulation layers. Then there are annealing of isolation and active layers. This combination of annealing processes improves the characteristics of structures. Conclusions. The optimum route, the annealing mode of the structures are determined in the work, and it is shown that monitoring the changes in the etching kinetics of silicon layers in the region of thermal immigration of aluminum impurities helps in determining optimal regimes.

Aging Properties of Insulation Coating for High and Low Voltage Electric Wires

Aging Properties of Insulation Coating for High and Low Voltage Electric Wires

Influence of electrode arrangements on Electrohydrodynamics and transport phenomenon within water and porous samples connected to rectangular duct

A numerical study based on the concept of conjugate transport phenomena analysis has been developed for the investigation of heat transfer and fluid flow within a rectangular duct and a sample by Electrohydrodynamics technique. High electrical voltage and average velocity of inlet hot-airflow are applied at 20 kV and 0.1 m/s, respectively. Electrode arrangements or angle between electrode and ground are varied in a range of θ = 0–360°. The effect of swirling flow on EHD-enhanced heat transfer is also examined. The results show that electric field from various angles can induce the difference swirling flow pattern. By fluid flow within the sample is depended on the swirling flow and hot-airflow direction. Besides the shear flow effect, swirling flow is affected by temperature distribution. Therefore, it affects the sample. Furthermore, fluid flow from swirling flow effect and sample properties is the main mechanism of natural convection and conduction modes, respectively. Finally, the comparison of heat transfer enhancement between water sample and porous sample are also presented.

Electrospraying assisted by pressurized gas as an innovative high-throughput process for the microencapsulation and stabilization of docosahexaenoic acid-enriched fish oil in zein prolamine

Zein, a prolamine obtained from maize, was employed to encapsulate a fish oil highly enriched with docosahexaenoic acid (DHA) by an innovative process termed electrospraying assisted by pressurized gas (EAPG). This technology combines high electric voltage with pneumatic spray to yield a high-throughput encapsulation process. Semi-spherical zein flowable capsules with mean sizes of 1.4 μm containing the DHA-enriched fish oil were produced by EAPG from inert ethanol solutions at room conditions, presenting a high encapsulation efficiency. The oxidative stability tests carried out in the zein microcapsules obtained by EAPG showed that the DHA-enriched fish oil was efficiently protected over storage time. Sensory tests were also performed on fortified reconstituted milk with the freshly prepared zein/DHA-enriched fish oil microcapsules, suggesting negligible oxidation effects after 45 days. The results described herein indicate that EAPG is a promising innovative high-throughput electrospraying-based methodology for the encapsulation of bioactives and, therefore, the resultant DHA-enriched fish oil containing microcapsules can be industrially applied for the formulation of fortified foods. An innovative process, termed electrospraying assisted by pressurized gas (EAPG), is herein originally presented as a novel encapsulation methodology. This technology is based on the combination of high voltage and pneumatic spray, allowing the formation of microcapsules at room temperature conditions. Thus, EAPG shows a great deal of potential to encapsulate nutraceuticals and other bioactives that are sensitive to thermal degradation and/or oxidation. The resultant bioactive-containing capsules can be, thereafter, applied to develop novel fortified food products.