Arc Model Research Articles

Petrogenesis and tectonic significance of the middle Neoproterozoic highly fractionated A-type granite in the South Qinling block

AbstractThe South Qinling block, a segment of the Yangtze craton involved in the Qinling–Dabie orogen, is critical for understanding the tectonic evolution of eastern China. However, the tectonic setting of the South Qinling block and the northern margin of the Yangtze block during middle Neoproterozoic time has long been the subject of debate, with two distinctly different models (continental rift or volcanic arc) proposed. Here, a comprehensive study of zircon U–Pb geochronology and geochemistry has been carried out on the Chengwan granitic pluton from the Suizao terrane in the South Qinling block. The granites are monzogranite and syenogranite in lithology, and are mainly composed of potash feldspar, quartz, plagioclase and biotite. This suite has long been regarded as a Palaeozoic magmatic pluton, but zircon U–Pb ages of 809 ± 9 Ma and 816 ± 4 Ma are obtained in this study. The granites are metaluminous to strongly peraluminous with high alkali contents, and exhibit highly fractionated features, including high SiO2, low Zr/Hf ratios, rare earth element tetrad effects and enrichment of K and Rb. They show Hf–Nd isotopic decoupling, which may be genetically related to their petrogenetic process. Based on the geochemical features and the positive εHf(t) values of the zircons, it is indicated that the granites may have been derived from partial melting of juvenile tonalitic rocks by biotite breakdown under fluid-absent conditions. The Chengwan granite geochemically belongs to the A2-subtype granites, suggesting that it might have formed in a post-orogenic tectonic setting. The highly fractionated A-type granite in this study may represent extensional collapse shortly after the collisional events in the South Qinling block, and thus indicate a tectonic regime switch, from compression to extension, as early as middle Neoproterozoic time. Integrating our new data with documented magmatic, metamorphic and sedimentary events during middle Neoproterozoic time in the region may support a continental rift model, and argues against arc models.

Three-dimensional non-equilibrium modeling of a DC multi-cathode arc plasma torch

In this paper, a three-dimensional non-equilibrium steady arc model is used to investigate the temperature, velocity and electromagnetic field in multi-cathode arc torch, and the formation mechanism of a large-area, uniform and diffused arc plasma is analyzed. The numerical simulation results show that a large volume plasma region can be formed in the central region of the generator during discharge. During this process, the maximum electron temperature appears near the cathode and in the central convergence region, while the maximum heavy particle temperature only appears in the central convergence region. This phenomenon is consistent with the experimental arc images. Near the cathode tip, the arc column is in a contraction state. In the area slightly away from the cathode, the six arc columns begin to join together. In the plasma generator, there is a large-scale current distribution in all directions of X, Y and Z, forming a stable arc plasma with a wide range of diffusion. The calculated electron temperature distribution is in good agreement with the measured electron temperature. The results suggest that the large-area diffused arc plasma in the multi-cathode arc torch is the combined effect of current distribution, convection heat transfer and heat conduction.

Parameter estimation of DC black-Box arc models using genetic algorithms

This paper presents a method for estimating the black-box arc parameters using genetic algorithm. The proposed method is applied to represent a DC short-circuit in a railway system protected by a High-Speed Circuit Breaker (HSCB). The simulated cases were compared with experimental data, and the results show very good agreement between model predictions and experiments. This method could potentially be used by HSCB’s manufacturers to extract and provide arc model parameters to end users based on their test results.

A statistical-based criterion for incipient fault detection in underground power cables established on voltage waveform characteristics

The incipient faults which mainly occur due to the electric arc occurrence in the power cables with insulation defects are hardly detectable by the conventional protective relays, and over time can develop into a permanent fault in the system. Employing Kalman filter, this paper puts forward a method to detect the incipient faults and to discriminate them from other similar incidents in the power system. The proposed method is established on the comparison between the waveform of the measured voltage and fundamental component of the measured voltage, estimated by Kalman filter algorithm in the sending end of the cable during the fault. Employing the difference between the measured and estimated waveforms, the incipient fault detection and discrimination are carried out within two stages. In the first stage, event detection is relegalized by comparing the standard deviation of the obtained error with a certain threshold. The second stage is conducted to find the incipient fault based on the non-attenuating characteristic and quasi-periodic nature of the incipient fault. The feasibility of the proposed method is verified through computer simulation using four different electric arc models and also the acquired experimental data from real incipient faults.

Parameter identification of DC arc models using chaotic quantum cuckoo search

DC arc fault is difficult to be detected, which brings great challenge to the safety of DC distribution system. The investigation of arc fault detection based on simulation method is able to reduce the cost and contributes to the research in the system where it is not suitable to carry out experiments. Accurate arc model is the foundation of simulation research. To address the gaps existing in arc models and corresponding parameter identification methods, two novel arc models and a new optimization algorithm are presented in this paper. First of all, hook static model was proposed to describe the nonlinearity near the transition point in static curve of arc. Then, segmented noise model was developed to flexibly fit the diversiform shape of arc noise’s frequency spectrum (FS). Finally, in order to improve the accuracy of parameter identification of arc models, this paper introduced chaos mechanism into quantum cuckoo search (CQCS): using chaotic map to initialize the population and generate the random parameter p; using lifespan based chaotic local search to further update the position of best solution. Based on the data obtained from established experimental platform, the effectiveness of the proposed models and optimization algorithm is verified. Meanwhile, compared with the existing methodologies, the proposed models and optimization algorithm are of better performance.

ArcNet: Series AC Arc Fault Detection Based on Raw Current and Convolutional Neural Network

AC series arc is dangerous and can cause serious electric fire hazards and property damage. This article proposed a convolutional neural network -based arc detection model named ArcNet. The database of this research is collected from eight different types of loads according to IEC62606 standard. The two most common types of arcs, including arcs from a loose connection of cables and those caused by the failure of the insulation, are generated in testing and included in the database. Using the database of raw current, experimental results indicate ArcNet can achieve a maximum of 99.47% arc detection accuracy at 10 kHz sampling rate. The model is also implemented in Raspberry Pi 3B for classification accuracy. A tradeoff study between the arc detection accuracy and model runtime has been conducted. The proposed ArcNet obtained an average runtime of 31 ms/sample of 1 cycle at 10 kHz sampling rate, which proves the feasibility of practical hardware deployment for real-time processing.

Impedance Arc Model Considering High-Frequency Characteristics of Fault Arc Current

Impedance Arc Model Considering High-Frequency Characteristics of Fault Arc Current

Study on Arc Extinguishing Performance of DC C4F7N/CO2 Mixed Gas

The arc characteristic analysis of C4F7N/CO2, CO2 and SF6 gases with volume fraction of 10%C4F7N-90% under DC condition is studied. Firstly, based on the internal physical process of arc, a two-dimensional axisymmetric arc model of C4F7N/CO2, CO2 and SF6 gas was established and calculated. The arc temperature distribution and dynamic characteristics of three gas media are compared and analyzed the results show that the temperature distribution of C4F7N/CO2 mixed gas is more similar to that of SF6 gas arc, and its radial cooling speed is faster, indicating that compared with CO2 gas, C4F7N/CO2 mixed gas has better arc-quenching characteristics, which can be used in the study of SF6 substitute gas.

Generalized Mayr Model for Arcs in MV Switches With Splitter Plates

The effect of splitter plates (SP) on current interruption at medium voltage (MV) level is theoretically investigated in the framework of Mayr&#x0027;s arc model, which is generalized to take into account the electrode fall voltage, <i>V</i>₀, of the SP. The model is analytically solved in the current zero (CZ) region where the current (before CZ) and the voltage (after CZ) can be linearized with respect to time. The current turns out to be successfully interrupted if the total electrode fall voltage, <i>NV</i>₀, for <i>N</i>&#x00A0;&#x2212;&#x00A0;1 SP plus contact electrodes, is larger than twice the transient recovery voltage, <inline-formula><tex-math notation="LaTeX">${\boldsymbol{U}} \approx {\dot{\boldsymbol{U}t}}$</tex-math></inline-formula>, at the characteristic arc decay time, <i>t &#x003D; &#x03C4;</i>, after CZ: <inline-formula><tex-math notation="LaTeX">${\boldsymbol{N}}{{\boldsymbol{V}}_0} &gt; 2{\dot{\boldsymbol{U}\tau }}$</tex-math></inline-formula>. For <inline-formula><tex-math notation="LaTeX">${\boldsymbol{N}}{{\boldsymbol{V}}_0} &lt; 2{\dot{\boldsymbol{U}\tau }}$</tex-math></inline-formula>, an additional thermal condition must be satisfied, where also the current rate, <inline-formula><tex-math notation="LaTeX">${\dot{\boldsymbol{I}}} = {\boldsymbol{\ dI}}/{\boldsymbol{dt}}$</tex-math></inline-formula> before CZ, and the arc cooling power, <i>K</i>, are involved. The intuitive results lead to a simple understanding of the electrical effect of SP on current interruption at MV and serve as an initial design rule for the number of SP in different gases.

Spatially resolved LAAS diagnostics of a free-burning ar arc: Analysis of line broadening

Spatially resolved laser atomic absorption spectroscopy (LAAS) diagnostics are applied to a free-burning DC arc in argon at atmospheric pressure. The novel LAAS apparatus is capable of mode-hop free wavelength tuning over the larger range than in conventional systems (up to 300 GHz in the present work). It allows for the measurements of both the absorption coefficient and the spectral line profile continuously from the hot arc center to the non-equilibrium arc wings. The results of such measurements are presented in this work with the emphasize on the combined analysis of laser absorption, which gives densities of excited atoms, and line broadening, which delivers information on either electron density (in case of Stark broadening) or neutral atom density (in case of van der Waals broadening). Contributions by different broadening mechanisms (Stark, Doppler, van der Waals, Resonance) are separated and analyzed. Experimentally retrieved density and temperature profiles of electrons and neutral atoms are compared with the predictions of a self-consisted nonequilibrium arc model. Stark widths of Ar I lines 750.38, 751.46, and 763.51 nm are obtained in the temperature range of 11000–18000 K with the aim to extend the rather scarce data for those lines. The measured widths are compared with existing values from literature and theoretical predictions.

The Mayr-Pentegov Model of Electric Arc Involving the Use of the Exponential Function and Enabling the Approximation of Static Characteristics

The article presents the justified use of functions containing the exponential component for the approximation of the static current-voltage characteristics of electric arc. The Author proposed a new function approximating the above-named characteristics which were next used in the mathematical Mayr-Pentegov model, expressed in two, i.e. differential and integral, forms. The two forms constituted the basis enabling the development of macromodels using controlled voltage and current sources. The article also presents families of dynamic current-voltage characteristics obtained through the simulation of processes in a circuit containing macromodels of arc powered by the source of current characterised by sinusoidal and trapezoidal waveforms and various frequency. The article demonstrates the usability of the proposed variants of the Mayr-Pentegov model.

Tuning proportional-derivative controller for a three-phase electric arc furnace

In this paper is presented a control system that is based on the proportionalderivative controller for modeling and simulation of the electric arc furnace focusing on the controller’s loop. The proposed controller is used to modify the position of the electrodes of the electric arc furnace in order to minimize the effect of the disturbances that can appear in the process during its functioning. With the proposed controller can be obtain the maximum power that can be used during functioning of the electric arc furnace. Also, the proposed control system can be used to obtain a specific active power for the electric arc that appears in the functioning of the electric arc furnace. In this paper are presented the steps used to tune the proportional and derivative gains of the controller. Used mathematical model of the electric arc is based on the voltage-current characteristic of the electric arc that simulates the functioning of the electric arc from the electric arc furnace. The model is integrated in the control system implementation. The simulations are implemented using Simulink toolbox from Matlab software. Taking into consideration obtained results during simulation are selected the best values for the gains of the proportional-derivative controller in order to obtain performance optimization of the electric arc furnace. For the selected gains of the proportional-derivative controller is presented the response of the system that is tested in a closed loop.

Research on the effect of air flow extinguishing arc in double jet non-equilibrium field

A dual-jet arc-extinguishing method is proposed in order to improve the performance of jet-extinguishing gaps for extinguishing large currents and reducing the lightning trip-out rate of power lines. Meanwhile, we studied the arc-extinguishing effect of the dual-jet non-equilibrium field gas flow. Based on this, a Double Jet Arc Extinguishing Gap (DJAEG) is developed. First of all, the jet field arc extinction modeling analysis is carried out by coupling the typical MAYR arc model with the jet field. Then, the COMSOL MUTIPHSICS simulation software is used to simulate the arc extinction of the DJAEG in the balanced flow field and the non-balanced flow field. Finally, the DJAEG extinguishment arc test is carried out through the construction of the power frequency continuous flow interruption test. The simulation results show that the velocity of the high-speed jet emitted by the DJAEG can reach 3000 m/s, and the arc can be extinguished within 4 ms. These results also verified that the dual jet non-equilibrium flow field has the characteristics of long jet sustaining time. The test results show that the DJAEG successfully extinguished the arc within 4 ms, and there was no reignition. This means that the dual-jet non-equilibrium field has an obvious arc extinction effect.

Vacuum contactor operation with parallel connection of independent consumers

This work presents a model of a transformer substation with parallel connection of independent consumers via vacuum switches. Several options of an electric arc model are considered upon switching off a vacuum switch such as: KEMA model and “black box” model. Modern computer models of vacuum switches were analyzed. Since the model data were not suitable for the conditions of the experiment, a simulation computer model was developed that reflects the specifics of the operation of the substation and of the transition process upon disconnection of one or several vacuum switches. The results of the developed methodology of analyzing transition processes were verified. To check the results of computer simulation, an experimental model was constructed, it consisted of: an electric load (inductive nature), a power supply, two vacuum switches, and a measuring circuit. The circuit is switched on and off using a pneumatic system controlled by a microcontroller. The primary purpose of the work is to check mutual influence of vacuum switches upon parallel disconnection, since there may be a restrike caused by effects of switching overvoltage between neighboring switches upon irregular disconnection. The effects of a transition process in one switch on the total current of the entire system were identified. A stand for a projected trial was demonstrated as well.

A Case Study on Using Online Integrated Arts Psychotherapy Program for Stress Reduction in Adolescents: Based on ARC Model

A Case Study on Using Online Integrated Arts Psychotherapy Program for Stress Reduction in Adolescents: Based on ARC Model

An integrated approach to understanding RF vacuum arcs

Although used in the design and costing of large projects such as linear colliders and fusion tokamaks, the theory of vacuum arcs and gradient limits is not well understood. Almost 120 years after the isolation of vacuum arcs, the exact mechanisms of the arcs and the damage they produce are still being debated. We describe our simple and general model of the vacuum arc that can incorporate all active mechanisms and aims to explain all relevant data. Our four stage model, is based on experiments done at 805 MHz with a variety of cavity geometries, magnetic fields, and experimental techniques as well as data from Atom Probe Tomography and failure analysis of microelectronics. The model considers the trigger, plasma formation, plasma evolution and surface damage phases of the RF arc. This paper also examines how known mechanisms can explain the observed sharp field dependence, fast breakdown times and observed surface damage. We update the model and discuss new features while also pointing out where new data would be useful in extending the model to a wider range of frequencies.

Cascaded HVDC gaseous circuit breaker performance using black box arc model

The development of renewable sources of electrical energy represents the main goal of the most countries. This energy has to be transmitted for a long distance for the utilization in populated areas. The need of high-voltage direct current circuit breakers represents the key of the development of high-voltage direct current transmission systems. High and extra high-voltage six sulfur hexafluoride circuit breakers need more than one interrupter to be stable during arc extinguishes, so it can be used in high-voltage systems as cascaded interrupters. In this article, the multi-break high-voltage direct current HVDC gaseous circuit breaker characteristic is investigated by employing Mayr and Cassie arc models. The influences of the models parameters on the arc interruption time are studied using MATLAB/Simulink program. It is concluded that the simulated results by employing black box arc models achieve a success in multi-break HVDC gaseous circuit breakers simulation. Employing BBAMs black box arc models has proved more flexibility to study the effect of different controlled and uncontrolled parameters on the multi-break high-voltage direct current gaseous circuit breaker HVDCGCB arcing time. That has proved more flexibility to study the effect of different controlled and uncontrolled parameters on the arcing time. The main contributions of this article in points can be summarized as employing black box arc models achieves a success in multi-break HVDC gaseous circuit breakers simulation, investigation of the influence of commutation parameters on the cascaded HVDC gaseous circuit breaker interrupter performance, the controlled and uncontrolled parameters affecting the arcing time of HVDCGCB has been studied, the impact of the fault resistance value on arcing time and the damping resistance influence on the transient recovery voltage are investigated, and additionally, the initial transient interruption and the Metal Oxide Varistor voltages are analyzed. From the investigated forty cases done to check the Mayr’s model validity in the HVDC CD simulation, it is found that the values of P and τ which give acceptable outputs are at τ = 10−6 s, and P in range of 107 W to 1011 W. The output of the case τ = 10−6 s, P = 1010 W, which is introduced in the paper has proved that when τ reached to 10−7 s the MOV current rises and drops and thereafter rises and gradually decreases. This may leads to CB failure Com parameters influence on the interrupter performance are investigated and proved good simulation of the gaseous circuit breaker interrupter.

Modelling of Electric Arcs for Industrial Applications, a Review

Electric arcs are a necessary heat source in many industrial processes that take place in Submerged Arc Furnaces (SAFs). Arcs exhibit non-linear electrical characteristics and behave in a complex manner. Therefore, an improved understanding of their behaviour enables better control of furnace operation. Modelling of industrial arcs is a multiphysics process that involves simultaneously solving several coupled physical phenomena, such as electromagnetics, fluid dynamics and heat transfer, including a radiative heat transfer from the plasma arc. Coupling fluid dynamics and electromagnetics is known as Magnetohydrodynamics (MHD). There are also simpler approaches to arc modelling, either based on simplified physical principles or empirical behaviour. A number of MHD models for electric arcs have been presented in the literature, but most of them involve simplifications such as axial-symmetry to reduce the simulation time, pertain to currents much lower than for industrial arcs, focus on DC arcs rather than arcs carrying AC current or do not have the plasma properties of the actual gas in the furnace. In a recently started project, the ambition is to create a full-scale 3D MHD model for an industrial AC arc at the conditions to be found in Si-metal furnaces. As much can be learned from previous arc modelling, this paper will review different arc modelling approaches and develop a classification framework to categorize the modelling methods, both the more intricate MHD models as well as the simpler modelling approaches. Among the available simplified models, one will be selected and coupled with a submerged arc furnace electrical circuit model. The complete circuit model parameters such as resistances and inductances are updated using a 3D submerged arc furnace that has been developed in ANSYS Maxwell using an eddy current solver.

An Enhanced Cassie–Mayr-Based Approach for DC Series Arc Modeling in PV Systems

DC series arc faults are known as a great threat in photovoltaic (PV) systems that may lead to fire and electric shock hazards. This article concentrates on driving effective models based on Cassie and Mayr equations for dc series arc using actual recorded data. Despite Cassie and Mayr equations that use invariant parameters during arc modeling, the proposed models employ the combinations of both Cassie and Mayr equations in which the time-variant nature of arc’s coefficients is taken into account. While the original Cassie and Mayr equations have two influential parameters for arc modeling, the first model presents a developed Cassie–Mayr equation with three parameters. Also, to further improvement in the model’s accuracy, the second model presents a developed Cassie–Mayr equation with five parameters. While the first and second models provide more prevision comparing with the original Mayr and Cassie–Mayr modeling, a third model is presented that treats with parameters of the original model as time-series parameters. To obtain the arc’s coefficients, a new formulation for coefficient estimation based on Levenberg–Marquardt (LM) algorithm is presented. Evaluating the proposed models with the actual recorded data, the results show the proposed models have more accuracy in comparison with the original Mayr and Cassie–Mayr.

Experimental Research and Numerical Simulation of Single Soil‐Arc‐Grounding‐Fault in Distribution Networks

Among the distribution network faults, single‐phase grounding faults have the greatest probability. The faults are often accompanied by arcs in the grounding point soil. This type of fault current has a small amplitude and seldom can obtain field record data. A soil arc grounding fault is tested on a realistic‐distribution‐network‐experimental‐platform (RDNEP), and it is concluded that the soil‐arc‐grounding‐fault (SAGF) has three main characteristics: hysteresis, nonlinearity, and asymmetry. By comparing with the characteristics of common arc models, it is pointed out that common arc models cannot accurately fit the characteristics of SAGF. This paper proposes and establishes a double exponential function arc model. Through the comparison of simulation waveforms with experimental data, it is verified that the numerical simulation method proposed in this paper can simulate the development process of SAGF more accurately. Furthermore, the equivalence of RDNEP is verified on the real distribution network system (RDNS). On this basis, analyzed the arc characteristic changes of different SAGF development cycles. Finally, by studying the applicability of the proposed model in simulating ground faults in grass and gravel roads, it is verified that the model proposed in this paper has a strong generalization capability. The research has laid a theoretical foundation for a detection algorithm that is based on the characteristics of SAGF.