High-voltage Impulse Research Articles

Evaluation of standard impulse voltage/current measuring systems in Japan

AbstractA national‐standard‐class impulse voltage measuring system in Japan was developed in the consignment research of the Ministry of Economy, Trade and Industry (METI) and New Energy and Industrial Technology Development Organization (NEDO) from 1998 to 2006. The standard measuring system for the impulse voltage measurements is managed by the Japan High Voltage Impulse Testing Laboratories Liaison (JHILL) established under the Japan Electric Machine Industry Association (JEMA). The standard impulse voltage measuring system calibrates other measuring systems and assesses their uncertainties, and, therefore, its uncertainty needs to be evaluated independently. The principal components of the system are a voltage divider, a digital recorder, and a low‐voltage calibrator which generates impulse voltages of known peak voltages and waveforms. Moreover, a reference measuring system for impulse current in Japan was also developed in 2009 supported by JEMA. Its international compatibility was confirmed through an international comparison test. Through domestic comparison tests, traceability among transducers of impulse current in Japan was established. In this paper, the constitution of these measuring systems, their performance, and related latest activities, such as comparison tests, are described. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Impulse breakdown of water with different conductivities

The complexity of the impulse breakdown of liquid water is reflected by the dependency of pre-breakdown processes on the polarity, rise-time and wave-shape of the applied impulses as well as on physical properties, such as the electrical conductivity of water itself. Further understanding of the mechanisms of formation and propagation of impulse discharges in water and water solutions is therefore required to enable the development of pulsed power and plasma technologies. This paper presents a study of the dielectric behaviour of water stressed with positive and negative high voltage impulses in a point-plane electrode topology. Water with different conductivities including distilled water and tap water was investigated. The volt-time breakdown characteristic of water is discussed and the total pre-breakdown time has been obtained for both positive and negative polarity impulses for 2 mm, 5 mm and 10 mm inter-electrode distances. The Laue statistical analysis has been used in order to calculate the statistical and formative time lags. Using the formative time data the nominal breakdown velocity in water for positive and negative impulses has been obtained. It has been shown that the anode discharges propagate with supersonic velocities, up to ~20×105 cm/s, and the cathode discharges are sub-sonic with a maximal velocity of ~c1x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> cm/s. Discharge velocities are slightly higher in distilled water as compared with tap water. Potential breakdown mechanisms which can explain the observed polarity effects in the transient prebreakdown processes in liquid water stressed with high voltage impulses are discussed.

Inductive Pulsed Power Supply Consisting of Superconducting Pulsed Power Transformers With Marx Generator Methodology

We have been developing an inductive pulsed power supply (PS) consisting of several superconducting pulsed power transformers with Marx generator methodology. Each of these pulsed power transformers consists of a copper secondary winding and a high-temperature superconducting primary winding. In order to obtain a high-voltage impulse, the Marx generator should be charged via the parallel connection of capacitors and discharged via a series connection. In contrast, this superconducting pulsed PS is excited in series connection of superconducting primary windings and discharged in the parallel connection to obtain a large pulsed electric current. Our preliminary experiment result showed that the process of one transformer module was correct. In this paper, the characteristics and simulation results of the superconducting inductive pulsed PS are described.

Lightning protection of wind turbine blades

The causes of lightning damages of wind turbine blades were clarified through lightning observation and experiments using a high-voltage impulse generator. Upward leaders and large energy of winter lightning, which is frequent along the coast of the sea of Japan, play an important role upon lightning damages of wind turbine blades. Lightning discharges may penetrate into the cavity of a blade without lightning receptors, resulting in serious damages, such as an destruction and falling of a blade. Although lightning receptors are totally useful for lightning protection of wind turbine blades, they are not perfect.

A rapid 2-MV impulse generator

A high-voltage nanosecond impulse generator was developed and tested in order to create electromagnetic impulses (EMIs) in a given area. Tests revealed the characteristics of the generator’s output impulse: the rise (at a level 0.1–0.9) is about 3.2 ns, the length is 27 ns at half-deflation, and the magnitude is 2 MV. The generator is used to test large-size equipment for tolerance to industrial EMIs.

High-Voltage Ultra Wideband Coaxial Load With Distributed Ceramic-Carbon-Rod Resistor

An ultra wideband coaxial termination load is developed using a distributed ceramic-carbon-rod resistor for high-voltage fast transient impulse measurements. The difficulty in the development of a high-voltage ultra wideband termination device is a compromise in the size of the internal resistive element for optimizing performance between high-voltage insulation and wideband frequency operation. A smaller resistor shows better high-frequency performance but worse high-voltage insulation characteristics. In this letter, we propose a logarithmically tapered coaxial load device having wideband and high-voltage properties simultaneously. For high-voltage operation exceeding tens of kilovolts, a ceramic-carbon-rod resistor with distributed parameters is used as the termination element. For wideband frequency operation, we constructed a linearly decreasing coaxial characteristic impedance along the solid rod resistor for compensating impedance mismatch and maintaining consistent synthetic impedance in the entire load device. The implemented coaxial load shows a return loss under -18 dB from dc to 10 GHz, peak impedance variation under 8% with converged value of 54 Ω, and insulation performance up to 20 kV with a rise time of 100 ps.

Study on a Magnetic Switch for Pulsed Power Conditioning System

In order to protect the key elements (e.g., Xe flashlamps) from being damaged by the trigger impulse in pulsed power conditioning system (PPCS), a magnetic switch is used for isolating the high-voltage nanosecond impulse. The magnetic switch in PPCS is working along with the initial magnetization curve. The working principle and performance of the magnetic switch in PPCS is presented. Fe-based nanocrystalline is adopted as the material of magnetic core. According to the specific application, the dynamic characteristics of Fe-based nanocrystalline under nanosecond impulses were obtained experimentally. As the magnetization rate increases, the average relative permeability decreases due to magnetic viscosity and eddy current. The measured parameters of unsaturated inductance, saturated inductance, and saturation time are in agreement with the calculation ones. Finally, the experimental results of the magnetic switch in PPCS are presented.

A dual-modality system for imaging anatomy and vasculature in live mouse embryos

An imaging system that combined high-frequency ultrasound (HFU) with photoacoustics (PA) for in vivo visualization of anatomical and vascular maps in transgenic mouse embryos is presented. The system consisted of a five-element, 40-MHz, poly-vinylidenefluoride-co-trifluoroethylene (PVDF-TrFE) annular array with a hole in the center to facilitate coaxial delivery of light produced by a 532-nm pulsed laser. A phosphate buffer-filled petri-dish with a central hole was placed on the abdomen of an anesthetized mouse and a laparotomy was performed to expose an intact uterus. The probe was raster scanned to achieve 3-D imaging. The central element of the array was excited with a high-voltage impulse synchronized with the light pulse. The resulting ultrasound echo and PA signal from each scan location were digitized from all five array channels and synthetically focused in post-processing. The embryonic vasculature depicted by the PA image was co-registered with anatomical features represented in the HFU image. T...

インパルス高電圧標準測定システム用校正器の開発

インパルス高電圧標準測定システム用校正器の開発

Natural laminar-turbulent transition delay by dielectric barrier discharge

The use dielectric barrier discharge for the delay of laminar turbulent transition excited by natural flow disturbances in a quiet wind-tunnel was investigated experimentally. Optimal electrodes location and the operational regime of high-voltage impulse generator provided maximal downstream shift of transition location were found. It was demonstrated that the 10% increase of the laminar part of boundary layer can be obtained using barrier discharge with the cross-flow electrodes. This gives up to 20% friction drag reduction.

Study of a Magnetic Switch for the SG-III Energy Module

The SG-III energy module, which supplies pumping energy for Xenon (Xe) flashlamps, is one of the most important modules in large laser facilities. A two-electrode spark gap switch is used as the main discharge switch and is triggered by a Marx generator. The peak value of the output impulse generated by the Marx generator is about 180 kV, and its rise time is about 10 ns. In order to prevent the key elements (e.g., Xe flashlamps) from being damaged by the trigger impulse, a magnetic switch is used to isolate the high-voltage impulse. The design, working principle and performance of a magnetic switch based on Fe-based nanocrystals are presented in this paper. Compared with the magnetic switch employed in magnetic pulse compressors (MPCs), the magnetic switch in SGIII works under a single nanosecond impulse. It corresponds to the initial magnetization curve of the B-H curve. The parameters of the Fe-based nanocrystals are obtained by experiments. The unsaturated inductance, saturated inductance and saturation time are the key parameters of the magnetic switch in SG-III and are considered in the design. Finally, the experimental results for the magnetic switch in SG-III are presented.

Generating extra long arcs using exploding wires

Long electrical arcs that are created using high voltage impulses in air gaps require average electric fields (AEFs) in the order of 100 to 1000 kV/m. In this paper, a method is presented where arcs can be created using AEFs of just 4.5 kV/m. The results from experiments up to 60 m long are used to form a mathematical model that predicts the occurrence of arc formation. The parameters of the energy supply, namely the voltage and capacitance, are found to determine the length of the arc that can be obtained. This model can be used by other research groups to reliably create long arcs; it is shown that many high voltage laboratories already have equipment capable of producing arcs several hundred meters long by using this method.

고전압 임펄스를 적용한 막분리 공정에서의 생물막 오염 제어에 관한 연구

Although membrane technologies are widely applied to the water and wastewater treatment processes, strategy for the control of membrane biofouling is strongly required. In this study, a possibility of control of membrane biofouling using HVI(High Voltage Impulse) was verified based on the inactivation of microorganisms by the HVI. The HVI system was consisted of power supply, voltage amplifier, impulse generator and disinfection chamber and the model microorganism was E. coli. When 15[kV/cm] of electric fields was applied to the E. coli solution, inactivation of the microorganism was found. A possibility of the control of membrane biofouling using HVI was verified with experiments of membrane filtration with and without exposure of the HVI to biomass solution. Another membrane filtration experiments with the contaminated membranes by E. coli solution were carried out and indicate that the HVI could be used as an alternative method for membrane biofouling control. A series of simulation of the electric fields between electrodes and microorganisms was carried out for the visualization of the disinfection that showed where the electric fields are formed.

Evaluating on Effect of HVAC Series with Impulse Excitation Voltage on Porcelain Insulator by Using Rotating Wheel Dip Test

This paper presents the effect of over-voltage damage on contamination surface of porcelain insulator due to impulse high voltage connects in series with high voltage alternating current (HVAC) which studied by using rotating wheel dip test. This method is artificially accelerated ageing at short period and mostly resemble real application of insulator. To evaluate this effect, the frequency of leakage current (LC) waveform has been analyzed by fast Fourier transform. The results of the experiment showed that effect of HVAC series with impulse excitation voltage created a LC like as transient state which it is highest amplitude peak values of LC flow on the specimen surface. The partial discharge on specimen surface suddenly occurs after excite by both excitation voltage at few number of cycles and increasing depends on number of cycles.

One-Time-Implantable Spinal Cord Stimulation System Prototype

A prototype of a one-time-implantable spinal cord stimulation (SCS) system using wireless power and data-transmission techniques is presented in this paper. The power of the implant is induced by wireless coil coupling, and duplex amplitude-shift keying-load-shift keying wireless communication is used so that digital packets can be transmitted by the same inductive link. The proposed novel ASK demodulator attains high demodulation performance and small area without using any resistors and capacitors. The proposed SCS system utilizes many power saving schemes to reduce power dissipation (e.g., dual supply voltages on-chip, high-voltage impulse generation using small current, etc.). Meanwhile, the excess energy induced by the coils is stored in a rechargeable battery to extend the implant's operation time so that the number of battery replacement surgeries will be reduced significantly. The system-on-chip (SOC) is physically implemented on silicon and integrated in the implant as the system controller. The fabricated SOC area is 1410 × 1710 μm(2). Compared with existing commercial products, the proposed SCS system attains better flexibility and longer operation time.

Measurement Uncertainties of Impulse Parameters Due to Nonideal Step Responses of High-Voltage Dividers

Using the new definitions and analysis specified in the 2010 version of the IEC standards to calculate impulse parameters, this paper investigates the measurement errors and uncertainties of high-voltage impulse dividers due to their nonideal step response using the convolution method. Measured step responses of three different dividers and a range of practical impulse waveforms were used in the calculations. The obtained results indicate, for the first time, that the uncertainty contribution of a nonideal step response can be estimated with sufficient accuracy for the purpose of measuring practical impulse waveforms.

Portable High Voltage Impulse Generator

This paper presents a portable high voltage impulse generator which was designed and built with insulation up to 20 kV. This design was based on previous work in which simulation software for standard waves was developed. Commercial components and low-cost components were used in this work; however, these particular elements are not generally used for high voltage applications. The impulse generators used in industry and laboratories are usually expensive; they are built to with stand extra high voltage and they are big, making them impossible to transport. The proposed generator is portable, thereby allowing tests to be made on devices that cannot be moved from their location. The results obtained with the proposed impulse generator were satisfactory in terms of time and wave forms compared to other commercial impulse generators and the standard impulse wave simulator.

Anomalous diffusion of water molecules in disperse mineral media

Gas adsorption relaxometry was used to study the effect of high-voltage nanosecond impulses on the structural condition of surfaces and the adsorption properties of sulfide minerals. It was established that the diffusion of water molecules into the samples was anomalous. An increase in time of impact of nanosecond impulses was accompanied by decrease in the time of adsorption equilibration.

High voltage impulse electric fields: Disinfection kinetics and its effect on membrane bio-fouling

A high voltage impulse (HVI) technique was applied for the control of membrane bio-fouling caused due to the filtration of microorganisms. Escherichia coli was used as a model microorganism for membrane filtration. The death rate of the cells increased with increasing electric fields (E) strength from 5 to 20 kV/cm. In particular, the cell numbers decreased from 3.7 × 10 5 to 2.5 × 10 3 CFU/ml (99.3% reduction) when subjected to an HVI of 20 kV/cm for 60 min. The model equation for HVI disinfection; E 1.94 · t = 1.3 × 10 4, was obtained by plotting the contact time (t) vs. E for 2-log removal (99% reduction) of microorganisms. E. coli Suspensions, both with and without HVI induction, were filtered through an ultrafiltration membrane to verify if the HVI enhanced the filtration performance. The flux of the suspension subjected to HVI was constantly maintained throughout the entire filtration period; whereas, that of the control (without HVI induction) abruptly decreased after the onset of membrane filtration. The main reason for the improved flux was the reduced cake resistance (R c) as a result of the increased cell particle sizes after HVI induction. E coli cells became coagulated after being subjected to HVI and; thus, the particle size increased. The HVI system could be used as an alternative method for the control of membrane bio-fouling.

Design and Performance of a Resistive-Divider System for Measuring Fast HV Impulse

A measuring system based on a resistive divider using a copper sulfate (CuSO4 solution) has been developed to measure high-voltage impulses with rise times of several tens of nanoseconds. The response and temperature characteristics of the resistive divider have been studied. The divider has excellent response characteristics (<; 1-ns theoretical rise time) and good immunity from interference from a Marx generator and spark-gap switch. Stray parameters of the resistive divider are theoretically calculated, and their influences on the square-wave response are studied by Alternative Transients Program/ ElectroMagnetic Transient in DC System simulations. The measuring system is shielded using coaxial construction techniques. The experimental results show that it is capable of maintaining the output impulse of the Marx generator with rise time of 13 ns and amplitude of 170 kV.