Low Voltage Pulse Research Articles

Enhanced non-viral gene delivery via calcium phosphate/DNA co-precipitates with low-voltage pulse electroporation in NK-92 cells for immunocellular therapy.

Achieving high cell transfection efficiency is essential for various cell types in numerous disease applications. However, the efficient introduction of genes into natural killer (NK) cells remains a challenge. In this study, we proposed a design strategy for delivering exogenous genes into the NK cell line, NK-92, using a modified non-viral gene transfection method. Calcium phosphate/DNA nanoparticles (pDNA-CaP NPs) were prepared using co-precipitation methods and combined with low-voltage pulse electroporation to facilitate NK-92 transfection. The results demonstrated that the developed pDNA-CaP NPs exhibited a uniform diameter of approximately 393.9 nm, a DNA entrapment efficiency of 65.8%, and a loading capacity of 15.9%. Furthermore, at three days post-transfection, both the transfection efficiency and cell viability of NK-92 were significantly improved compared to standalone plasmid DNA (pDNA) electroporation or solely relying on the endocytosis pathway of pDNA-CaP NPs. This study provides valuable insights into a novel approach that combines calcium phosphate nanoparticles with low-voltage electroporation for gene delivery into NK-92 cells, offering potential advancements in cell therapy.

Effect of Pulse Width and Intensity on Cell Death in Reversible Electroporation of Cancerous Cells

Electroporation (EP) is the process of increasing the permeability of a biological cell or tissue by applying a short-term and sufficient external electric field. The utilization of proper pulse settings is required for EP-based treatments to be successful. Our aim in this study is to examine the effect of different electrical pulse widths and strength on EP efficiency. Human osteosarcoma cells (U20S) were used in the study. Eight-square-pulses with a frequency of 1Hz at 10µs, 1ms, 5ms, 10ms, and 20ms widths with low electric fields (20-500V/cm) were applied to U20S cells. 10-15 minutes after the applications, the cells were incubated in 96-well plates with 10 thousand cells in each well for 24 hours. Efficiency of pulses of different intensity and width was evaluated by MTT analysis method. The percent inhibition of U20S cancer cells elevated as the pulse width increased in almost all electric field values. The highest cell inhibition (%) occurred in pulses with an electric field of 500 V/cm and a width of 20ms (inhibition ratio: 76.25%). No inhibition was observed in the cells at 10µs, 1ms, 5ms, 10ms width pulses with 20 V/cm electric field and 10µs, 1ms width pulses with 50V/cm electric field. In conclusion, our findings show that the electric field intensity and pulse width used in electroporation play an important role in U20S cancer cell death. According to our results, it may be more appropriate to use high-voltage short-width pulses or low-voltage long-width pulses in reversible EP studies.

Refractive Laser Beam Measuring Diffusion Coefficient of Concentrated Battery Electrolytes

A thorough understanding of electrolyte transport properties is crucial in the development of alternative battery technology. As a key parameter, the diffusion coefficient offers important insights into the behavior of electrolytes, especially for fast charge of high-energy batteries. Existing methods of measurement are often limited by redox species or offer questionable accuracy due to side reactions and/or disruption of the diffusion profile. A highly sensitive optical method was developed using a refractive laser beam through triangular diffusion column to measure the diffusion coefficient of concentrated battery electrolytes. The method based on Snell’s law can be applied to all liquid phase electrolytes since the refractive index is concentration dependent for all liquid electrolytes. This universal method relies on the deflection of a refractive laser beam passing through an electrolyte of a minor concentration gradient in a triangular diffusion column (Figure 1). A polarized HeNe laser was arranged to pass the beam through a right-angled triangular quartz precision cell, slightly rotated to the normal. The exact position of the refracted beam was located by a silicon photodiode-based position detector. Deflection calibration curves made simple conversion of beam position to concentration, and during the diffusion of two layered solutions, data points were collected every minute to produce a concentration profile descriptive of the 48-hour diffusion. Diffusion coefficients were calculated using a model based on OSM theory, accounting for multi-component concentrated systems in a restricted diffusion column.1 The measured diffusion coefficients are between 4.12x10-10 m2/s for 0.15 mol/kg ZnSO4 and 0.681x10-10 m2/s for 2.5 mol/kg ZnSO4 at 22.4 °C. The profile of concentration-dependent diffusion coefficients follows a non-linear inverse relationship described by the function D=4.943(1+m)-1.564 (Figure 2).Several other physicochemical properties of the same electrolytes were studied to correlate to the concentration-dependent diffusion coefficients, including refractive index, viscosity, conductivity, and microstructure analysis based on vibrational spectroscopy (Infrared and Raman). High concentration electrolytes with more ion pairs show increased viscosity which ultimately leads to smaller diffusion coefficients. A QCM-I instrument standard flow cell were used to determine the viscosity of ZnSO4 electrolyte and the concentration-dependent viscosity was fitted to the function η=1.06-0.476m+2.13m2-1.01m3+0.204m4. Interionic interactions also led to reduced conductivity at concentrations beyond 1.5mol/kg, despite the increased charge density of concentrated solutions. FT-IR spectrums allowed analyzation of increased charge density, which increased intensity of the O-H stretching peak in concentrated electrolytes, despite the decrease in the ratio of water. Competition between charge density and viscosity continues to challenge the efficiency of concentrated electrolytes.Lastly, we demonstrate the prototype in situ triangular cell to characterize the electrolyte in working batteries. The cell responds to short, low-voltage pulses with beam deflection and relaxation, and offers an opportunity as a novel in situ spectroscopic tool to characterize the battery electrolyte. Acknowledgments This work is supported by a grant from NSF (CBET-2243098).

Enhancement of plasma assisted ignition by multi-voltage pulse discharges: A theoretical study

Currently, compression ignition engine technology is becoming less competitive compared to spark ignition engine technology due to emission standards. Lean combustion strategies are preferable for spark ignition engines, but they require enhanced ignition strategies compared to current stoichiometric spark ignition engines. In this paper, we lay physical foundations for such enhanced ignition strategies that can support lean combustion strategies in spark ignition engines. In this theoretical study, we conduct a preliminary foray into the possibility of controlling the species composition of a cold-plasma kernel as a precursor for an ignition process. We consider a multi-pulse electric source system coupled to a DBD (Dielectric Barrier Discharge) electrode immersed in a dry air medium. The coupled system is designed such that the medium in the electrodes’ gap is subjected to a pulse structure which is composed of a peak voltage followed by a secondary low-voltage pulse. Use is made of a comprehensive mathematical model that includes the electric field, potential and current, with the relevant conservation equations for 24 species and 168 kinetic reactions, while considering different energy modes (rotational, vibrational, electronic excitation, dissociation, and ionization) within the electrodes’ gap. The model was validated against independent published results, and was used to understand the mechanism of energy conversion to species that play a central role in terms of the ultimate ignition dynamics. Various pulse repetition frequencies and different pulse constructions were considered. Special attention was given to the amount of deposited energy, and to the energy channeled to known ignition supportive modes and species. The present results show that the energy deposition can be divided into two main stages which are characterized by high and low voltage levels, respectively. We propose that for more successful ignition, the amount of energy deposition during the second (low voltage) stage should be higher than that during the first (high voltage) stage. During the second stage, the deposition of energy into specific modes can be fine-tuned by setting appropriate voltage levels. Based on these findings, we demonstrate how control of the sequence of voltage pulses can further increase enhancement of ignition and combustion promoting processes.

The Enhancement of Tumor Ablation Effect by the Combination of High-Frequency and Low-Voltage Bipolar Electroporation Pulses.

Recently, combining short high-voltage IRE monopolar pulses with long low-voltage IRE monopolar pulses was shown to enlarge the ablation region. This finding indicates that combining HFBPs with low-voltage bipolar pulses (LVBPs), which are called composited bipolar pulses (CBPs), may enhance the ablation effect. This study designed a pulse generator by modifying a full-bridge inverter. The cell suspension and 3D tumor mimic experiments (U251 cells) were performed to examine the enhancement of the ablation effect. The generator outputs HFBPs with 0-±2.5 kV and LVBPs with 0-±0.3 kV in one period. The pulse parameters are adjustable by programming on a human-computer interface. The cell suspension experiments showed that CBPs could enhance cytotoxicity, as compared to HFBPs with no cell-killing effect. Even at lower electric energy, the cell viability by CBPs was significantly lower than that of the HFBPs protocol. The ablation experiments on the 3D tumor mimic showed that the CBPs could create a larger connected ablation area. In contrast, the HFBPs protocol with a similar dose generated a nonconnected ablation area. Results indicate that the CBPs protocol can enhance the ablation effect of HFBPs protocol. This proposed generator that uses the CBPs principle may be a useful tool for tumor ablation.

A comprehensive circuit and modulation design of mixed frequency conversion cascaded power electronic transformer

The power electronic transformer (PET) is one of the promising equipment of the energy Internet. In a distributed network, cascaded (cascaded full-bridge, CFB)-type PETs can withstand high-voltage stress and contain a low-voltage DC (LVDC) port, which provides access for distributed generation (DG). However, the hardware cost of the traditional CFB-type topologies remains high, and structure compactness can still be improved. The recently presented mixed-frequency conversion cascade PET (MFCC-PET) is one of the promising solutions. In this study, a comprehensive circuit design of MFCC-PET, a low-voltage distortion nearest-level pulse width modulation (NL-PWM), and a sub-module (SM) voltage balancing strategy for the proposed modulation method under mixed-frequency conversion are presented. A 100 V/2,000 W MFCC-PET prototype is built based on the above analysis and successfully placed into operation.

Liquid plasma discharge with low pulse voltage for efficient and ultra rapid removal of tetracycline hydrochloride and evaluation of its degradation pathway

Cathode liquid plasma discharge (LPD) is an efficient and ultra rapid method to degrade organic pollutants, mainly because it can produce a large number of strong oxidizing radical species during the process of plasma discharge. In this paper, the LPD process was firstly used to degrade the tetracycline hydrochloride (TCH) in water. The effects of the cathodic materials, pulse voltages, and anode-cathode distances on the degradation efficiency of the TCH were investigated, and the antibacterial activity and cytotoxicity of the degradation products were also evaluated. The results show that the degradation efficiency of the TCH can reach 98.13 % within only 1 min by the LPD process for initial concentration of 100 mg/L, and the TOC removal rate is maintained at over 81 % in 5 min. The Ti electrode performs the lowest ionic dissolution concentration and the solution near the cathode produces a plasma region for the degradation of the TCH, which contains a number of strong oxidizing radical species (such as ∙OH). The primary intermediate products (m/z = 445, 279, 149, and 123) and secondary intermediate products (m/z = 90.5, 81, and 59) are captured, and a possible degradation pathway of the TCH is also proposed. The cytotoxicity results show that the LPD degraded solutions are non-toxic effect on the NIH3T3 cells. The LPD process is a promising method to efficiently eliminate the TCH in wastewater. This work also provides a new experimental basis and reference for the ultra rapid degradation of organic pollutants in wastewater without using catalysts.

Electrolysis products, reactive oxygen species and ATP loss contribute to cell death following irreversible electroporation with microsecond-long pulsed electric fields

Membrane permeabilization and thermal injury are the major cause of cell death during irreversible electroporation (IRE) performed using high electric field strength (EFS) and small number of pulses. In this study, we explored cell death under conditions of reduced EFS and prolonged pulse application, identifying the contributions of electrolysis, reactive oxygen species (ROS) and ATP loss. We performed ablations with conventional high-voltage low pulse (HV-LP) and low-voltage high pulse (LV-HP) conditions in a 3D tumor mimic, finding equivalent ablation volumes when using 2000 V/cm 90 pulses or 1000 V/cm 900 pulses respectively. These results were confirmed by performing ablations in swine liver. In LV-HP treatment, ablation volume was found to increase proportionally with pulse numbers, without the substantial temperature increase seen with HV-LP parameters. Peri-electrode pH changes, ATP loss and ROS production were seen in both conditions, but LV-HP treatments were more sensitive to blocking of these forms of cell injury. Increases in current drawn during HV-LP was not observed during LV-HP condition where the total ablation volume correlated to the charge delivered into the tissue which was greater than HV-LP treatment. LV-HP treatment provides a new paradigm in using pulsed electric fields for tissue ablation with clinically relevant volumes.

The importance of the metal reinforcement of low voltage cables in the process of identifying defects

Regarding the identification of defect in the electrical energy cables, in exploatation, usual or high-performance methods are used, based in particular on the phenomenon of reflection and refraction of the impulse transmitted in the cable, phenomenon generated by the impedance change at the defect location. In order to identify the defect, an important role is played by the existence of a current path on the cable route between the ends of the electrical cable and the place where the defect occurred. In the case of low voltage cables, there are situations where, following the sleeve process the continuity of the mechanical protection armature of the steel strip or the copper screen has not been restored. To measure the distance to the defect location, location equipment uses low and high voltage pulses which moves to the defect site with a certain speed and which is repeated after a selected time interval. These impulses are transmitted to the location of the defect at one end of the cable, through the circuit generated by the short circuit between the faulted conductor and the metal armature, which is usually found at ground potential. At the same time, there is situations where the defect is difficult to identify precisely because of the continuity of the reinforcement or screen and their connection to ground potential. This paper describes the stages of fault identification in a low-voltage power cable and presents a case study that highlights the importance of the metal reinforcement in the case of the high-voltage impulse method. Ways to detect defects using the arc reflected method (ARM) using the shock wave generator as well as the inductive method are also briefly presented.

Pulse shape discrimination and spectral performance of an inverted coaxial point contact HPGe detector with sub-pF capacitance

The inverted coaxial point contact high purity germanium (ICPC HPGe) detector exhibits the advantages of large volume, low depletion voltage, small capacitance, and excellent pulse shape discrimination (PSD) capability. An ICPC detector prototype with 0.9 pF capacitance was successfully fabricated and tested in this study using two different front-end electronics. The detector weighted approximately 1.5 kg and the depletion voltage was only 1800 V. The optimized operating voltage was found to be 2500 V and the leakage current was 7 pA. The detector was first connected to a homemade JFET based front-end with a pulsed reset design to minimize parallel noise. An energy resolution of 1.72 keV (full width at half maximum) was achieved at 1332 keV, demonstrating the good charge collection efficiency of the detector. An RC feedback front-end circuit was employed to test the PSD properties using a 228Th source. The PSD capability is similar to that of typical broad energy or point contact HPGe detectors, but is notably improved when the charge trapping is corrected using the drift time.

Fluorine-modified CNT@epoxy electrothermal coating for long-term anti-icing at low pulse voltage

Long-term anti-icing technology is one of the important measures to solve the industrial development in low temperature environment, and is still one of the important challenges at present although it has been vigorously developed. Here, we design a fluorine-modified CNT@epoxy electrothermal coating by cooperating passive anti-icing of superhydrophobic surfaces with active deicing of electrothermal property. The coating exhibits excellent superhydrophobicity, low resistivity, robust durability, higher electrothermal response rate, freezing resistance, and rapid electrothermal thawing ability. Excitedly, our coating can delay the freezing time to 8 h by 15 V pulse voltage with frequency of 10 s/100 s under − 20 °C, which confirms the effectiveness by synergizing active de-icing and passive anti-icing at low pulse voltage. This work promises new solutions for surface applications related to long-term anti-icing, expecting to serve in cryogenic system and equipment, power transmission system, high-altitude vehicle, and so on.

Designing porous photonic crystals for MIR spectral region—a deeper insight into the anodic alumina layer thickness versus charge density relation

The mid-infrared region (MIR) is crucial for many applications in security and industry, in chemical and biomolecular sensing, since it contains strong characteristic vibrational transitions of many important molecules and gases (e.g. CO2, CH4, CO). Despite its great potential, the optical systems operating in this spectral domain are still under development. The situation is caused mainly by the lack of inexpensive and adequate optical materials which show no absorption in the MIR. In this work, we present an easy and affordable way to develop 1D photonic crystals (PCs) based on porous anodic alumina for MIR region. The porous PCs were produced by the pulse anodization of aluminum using charge-controlled mode. The first order photonic stopbands (λ 1) were located within ca. 3.5–6.5 μm. Annealing of the material at 1100 °C for an hour has allowed to recover the wavelength range from around 5.8 to 7.5 μm owing to the decomposition of the absorption centers (oxalate anions) present in the anodic oxide framework while maintaining the PC structural stability. The spectral position and the shape of the resonances were regulated by the charge passing under high (U H) and low (U L) voltage pulses, porosity of the corresponding d H and d L segments, and dura tion of the process (t tot). The thickness of the d H and d L layers was proportional to the charge passing under respective pulses, with the proportionality coefficient increasing with the applied voltage. Despite the constant charge (2500 mC cm−2) applied during the anodization, the thickness of anodic alumina (d) increased with applied voltage (10–60 V) and anodizing temperature (5 °C–30 °C). This behavior was ascribed to the different kinetics of the anodic alumina formation prompted by the variable electrochemical conditions. The photonic material can be used in portable nondispersive gas sensors as an enhancement layer operating up to around 9 μm.

A trigger source for linear transformer driver

A repetitive low jitter trigger source applied in triggering the multi-gap gas switch of the linear transformer driver (LTD) stage, is designed and developed in this paper.The pulse source based on fast Marx topology can repetitively output a low jitter high voltage pulse into a 50 Ω resistance load with peak value of 150 kV, rising time of 7 ns, width of 260 ns and rep-rate 0.1 Hz. Proper design of stray capacitance to peak the output pulse and employing the UV light to pre-ionize each consequent stage gap to reduce the switch delay time and jitter have been proposed. All those have been demonstrated feasible and reliable. A software program control unit has been developed for operation and control of fast Marx generator. The software gives full remote control by a computer via optical fiber communication. The experimental results show that the trigger source can continuously and reliably generate a 150 kV/260 ns pulse into a resistive load every 10 s with 1-σ jitter less than 2.7 ns. The trigger source is compact and portable and agrees well with the trigger demands of LTD for new fusion energy.

Gene Electrotransfer into Mammalian Cells Using Commercial Cell Culture Inserts with Porous Substrate.

Gene electrotransfer is one of the main non-viral methods for intracellular delivery of plasmid DNA, wherein pulsed electric fields are used to transiently permeabilize the cell membrane, allowing enhanced transmembrane transport. By localizing the electric field over small portions of the cell membrane using nanostructured substrates, it is possible to increase considerably the gene electrotransfer efficiency while preserving cell viability. In this study, we expand the frontier of localized electroporation by designing an electrotransfer approach based on commercially available cell culture inserts with polyethylene-terephthalate (PET) porous substrate. We first use multiscale numerical modeling to determine the pulse parameters, substrate pore size, and other factors that are expected to result in successful gene electrotransfer. Based on the numerical results, we design a simple device combining an insert with substrate containing pores with 0.4 µm or 1.0 µm diameter, a multiwell plate, and a pair of wire electrodes. We test the device in three mammalian cell lines and obtain transfection efficiencies similar to those achieved with conventional bulk electroporation, but at better cell viability and with low-voltage pulses that do not require the use of expensive electroporators. Our combined theoretical and experimental analysis calls for further systematic studies that will investigate the influence of substrate pore size and porosity on gene electrotransfer efficiency and cell viability.

Single-Step Genome Editing of Small Ruminant Embryos by Electroporation.

We investigated the possibility of single-step genome editing in small ruminants by CRISPR-Cas9 zygote electroporation. We targeted SOCS2 and PDX1 in sheep embryos and OTX2 in goat embryos, utilizing a dual sgRNA approach. Gene editing efficiency was compared between microinjection and three different electroporation settings performed at four different times of embryo development. Electroporation of sheep zygotes 6 h after fertilization with settings that included short high-voltage (poring) and long low-voltage (transfer) pulses was efficient at producing SOCS2 knock-out blastocysts. The mutation rate after CRISPR/Cas9 electroporation was 95.6% ± 8%, including 95.4% ± 9% biallelic mutations; which compared favorably to 82.3% ± 8% and 25% ± 10%, respectively, when using microinjection. We also successfully disrupted the PDX1 gene in sheep and the OTX2 gene in goat embryos. The biallelic mutation rate was 81 ± 5% for PDX1 and 85% ± 6% for OTX2. In conclusion, using single-step CRISPR-Cas9 zygote electroporation, we successfully introduced biallelic deletions in the genome of small ruminant embryos.

A Solid-State Pulse Adder for High-Voltage Short Pulses and Low-Voltage Long Pulses

The synergistic effect of high-voltage short pulses and low-voltage long pulse on cell electroporation can expand the tissue ablation area and enhance the irreversible electroporation effect. To meet the requirements of electroporation for pulse waveform, this article proposes a pulse generator which can output high-voltage short pulses and low-voltage long pulses cooperatively. The generator only uses one resonant power supply and uses magnetic rings with separate windings to control different charging voltages. The structure is relatively simple, and the output waveform can meet the experimental requirements. Finally, a prototype is built, in which the main circuit includes 14 switch tubes and 14 spring mud capacitors. The whole system can generate high-voltage short pulses with amplitude of 0–3 kV, a pulsewidth of 1– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 ~\mu \text{s}$ </tex-math></inline-formula> , and low-voltage long pulses with amplitude of 0–1 kV, a pulsewidth of 30– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150 ~\mu \text{s}$ </tex-math></inline-formula> . The delay between high voltage pulses and low voltage pulses is adjustable. At the same time through the control of driving timing, a seven-level step wave with amplitude of 2 kV can be generated.

Short circuit fault identification and diagnosis analysis of rotor winding for variable speed pumped storage unit

Rotor winding short circuit is a frequent fault type of generator unit. Compared with the traditional fixed-speed unit using DC excitation, the three-phase AC excitation structure of the variable speed pumped storage unit is more complicated, and the fault diagnosis of the rotor winding short circuit is more difficult. Therefore, this paper proposes an offline diagnosis method for variable speed pumped storage units based on the principle of Repetitive Surge Oscillograph (RSO). Firstly, the application scheme of the repeated pulse method in the variable speed pumped storage unit is designed. By injecting low-voltage pulses into three phases simultaneously and detecting the response curve to determine whether the unit has a short-circuit fault. Then, based on the response characteristics of different rotor winding short-circuit fault types, an identification scheme of rotor winding short-circuit fault types and faulty phases is proposed. Subsequently, the variational mode decomposition (VMD)-teager energy operator (TEO) method is used to estimate the injected pulse and characteristic curve’s initial sudden change position and then the fault position is determined by the time difference and the measured wave velocity. The simulation results show that the fault identification and fault location method proposed in this paper can be effectively applied to various rotor winding short-circuit faults of variable speed pumped storage units.

Nanoionics-based neuromorphic function of a Pt/Ti0.96Co0.04O2-δ /Pt multilayer device operating at low pulse voltage

We investigated the nanoionics-based neuromorphic function of Pt/Ti0.96Co0.04O2−δ /Pt multilayers with a cross-point structure prepared by RF magnetron sputtering. This multilayer exhibits electro-ion mixed conduction and a nonlinear current–voltage characteristic based on the Schottky barrier between Pt and Ti0.96Co0.04O2−δ layers. When the low electrical pulse of 0.8 V was applied with a short interval time of 14 s, current modulation corresponding to the long-term memorization (LTM) was observed, though the current response at the long interval time of 80 s was the short-term memorization (STM). The O 1 s photoemission spectrum showed the OH− peak that contributes to the electron-ion mixed conduction. The current responses with both LTM and STM are considered to be due to the local proton migration at near the Schottky barrier.

Investigating CO2 streamer inception in repetitive pulsed discharges

In this study, we investigate the responsible species and processes involved in repetitive pulsed streamer inception in CO2. We applied a 10 kV high-voltage (HV) pulse with a repetition frequency of 10 Hz and pulse width of 1 ms to a pin electrode which is placed 160 mm apart from the grounded plane electrode. We measured the inception times by a photo-multiplier tube (delay between the rising edge of the HV pulse and the rising edge of the photo-multiplier waveform) for 600 high voltage cycles. We observed one peak in the histogram of inception times with a median of 1.2 μs. To identify the source of this peak, we applied a negative or positive low-voltage (LV) pulse before the main HV pulse to manipulate the leftover space charges. Three different phenomena are observed: (1) drift, (2) neutralization, and (3) ionization in the LV pulse. At low LV amplitude and pulse width, the peak starts to drift toward the faster and slower inception times under a positive and negative LV pulse, respectively. However, under the same LV pulse configuration for positive and negative LV pulse, the observed shift in inception times is not the same. We present a hypothesis to explain this asymmetry based on the difference of the detachment processes between air and CO2.

Research on inter-turn short circuit fault location of SF6 circuit breaker energy storage motor coil based on traveling wave reflection method

—The traveling wave reflection method is proposed to locate the inter-turn short circuit fault of the circuit breaker energy storage motor coil. The capacitance and inductance matrices of the energy storage motor coil are calculated by finite element simulation, and the wave impedance model of the coil is established based on ATP-EMTP. The low-voltage square wave pulse signal is injected at the winding head to detect the characteristic curve of reflected wave when inter-turn short circuit fault occurs. The variation law of generalized fractal dimension of reflection wave characteristic curve with short circuit position is analyzed. The short-circuit position is evaluated based on BP neural network, and the evaluation accuracy is 100 %, indicating that this method is feasible.