Arc Extinction Research Articles

DFT study of Cun (n = 1–3) cluster-modified WSe2 monolayers for the detection of SF6 decomposition gases (H2S, SO2, SOF2 and SO2F2)

The role of SF6 in gas-insulated equipment is crucial for insulation and arc extinction. When subjected to electrical faults, thermal faults, and mechanical failures in insulation devices, SF6 can decompose into H2S, SO2, SOF2, and SO2F2. This study conducted first-principles simulations to analyze the effect of Cun (n = 1–3) cluster-modified monolayer WSe2 on sensing H2S, SO2, SOF2, and SO2F2 gases during SF6 decomposition. The optimal doping positions of Cun-WSe2 clusters at n = 1, 2, and 3 were determined, showcasing their superiority over pure WSe2 in terms of band gap, frontier orbitals, and density of states. Subsequently, a detailed investigation was carried out on the adsorption effects of the four gases at the optimal doping positions, including parameters such as adsorption distance, adsorption energy, charge transfer, differential charge density, and density of states. It was found that when the number of copper atoms in the cluster increased to 3, the banding energy sharply rose to -2.395 eV. Simulation results demonstrated the adsorption behavior of H2S on Cun (n = 1–3)-WSe2 demonstrates remarkable affinity, with an increasing adsorption energy as the number of Cu atoms rises. Notably, Cun (n = 1–3)-WSe2 exhibits favorable desorption times for SO2. At 378 K, the desorption time for SO2@Cu3-WSe2 is 14.7 s. At 498 K, desorption times for SO2@Cu1-WSe2 and SO2@Cu2-WSe2 are 7.59 s and 2.85 s, respectively. When the number of copper atoms is 2, the cluster-modified system desorbs SOF2 at room temperature in only 0.89 s. Moreover, Cun (n = 1–3)-WSe2 displays strong adsorption towards SO2F2, characterized by prolonged desorption times, rendering it a promising adsorbent for SO2F2 removal. This study aims to highlight the adsorption effects of different numbers of Cu atomic clusters in the Cun-WSe2 system on SF6 decomposition gas, further advancing research for developing high-performance SF6 decomposition gas sensors.

Research on arc evolution law of arc extin‐ction device under high‐speed large current

AbstractThe lifespan of the guide rail is a bottleneck restricting the operational life of electromagnetic railguns. A well‐designed arc extinguishing device can reduce the arcing erosion caused by residual currents within the guide rail. The CuW alloy is widely used in the high‐pressure arc extinction field due to its excellent electrical and thermal conductivity, high strength, and hardness. Based on the theory of equilibrium state arc plasma, a finite element model of the air arc‐CuW electrode coupling in the arc extinction device was established to study millisecond‐level arc initiation, evolution, extinguishing characteristics, and distribution patterns under extreme and harsh operational conditions with a current input of 110 kA. The highest temperature in the arc column region was found to exceed 50,000 K. The study elucidated the influence of arc extinction device parameters on arc evolution, breakdown time, and breakdown voltage. Consequently, it established that the R70 spherical electrode exhibits optimal arc extinguishing characteristics. The aim of this research is to provide theoretical support for optimizing the arc suppression device. Additionally, experiments on high‐speed and high‐current arc extinction device discharges were conducted to validate the finite element analysis results regarding arc diffusion patterns and electrode erosion.

Improved assembly DC circuit breaker based on resonant current injection.

DC circuit breakers (DCCBs) with high breaking capacity and low cost are necessary for quick fault clearance in DC networks. The assembly DC circuit breakers (ADCCBs) have a main breaking section (MBS) and a sub-breaking sections (SBS) for each line, which greatly reduce the cost. But in conventional operation, it bears high voltage for a long time when there is a main switch grounding process in any line fault action. To address this problem, a multiport assembly circuit breaker based on current injection (CI-MPACB) is proposed, which is able to generate a resonant current with increasing amplitude by controlling the duty cycle of Integrated Gate-Commutated Thyristors (IGCTs). Then the resonant current is injected into the SBS to generate current zero crossing and arc extinction. A complex frequency domain circuit analysis is performed on the MBS to describe the action logic as well as the commutation characteristics. In addition, the parameters of each component of the MBS are subject to multiple constraints and reasonable design to ensure the fault current could be cut off quickly and reliably. The cost of existing design is greatly reduced due to the design idea of resonant current injection device parameter selection. Finally, a PSCAD/EMTDC simulation confirms the opening viability of CI-MPACB and the accuracy of the parameter design. The test results show that the designed CI-MPACB can cut off DC fault lines.

Double closed loop PI control with full compensation arc elimination based on zero sequence voltage of neutral point

Aiming at the problem of zero sequence voltage generated by unbalance parameters of line to ground, which affects arc suppression effect of grounding fault of controllable voltage source. By analyzing the influence of ground unbalance parameters on the arc suppression effect of controllable voltage source under different grounding modes, the mechanism of full compensation arc suppression based on zero sequence voltage of neutral point is revealed, and on this basis, a fully compensated arc suppression model of controllable voltage source controlled by double closed loop PI is established, and the deviation control is carried out by using the neutral voltage of distribution network and the voltage of fault phase supply. The residual voltage ring adopts the ground fault phase residual voltage for closed loop control. The simulation results show that the dual-closed-loop PI control algorithm can continuously stabilize the output waveform of the controllable voltage source. When the transition resistance is 0.1 ~ 10 kΩ, the residual voltage stabilization time of the independent controllable voltage source grounding method is 43 ms ~ 2.4 s, and the parallel arc suppression coil grounding method is 43 ms ~ 4.7 s. The proposed dual closed-loop PI control method for neutral point voltage deviation and fault residual voltage can stabilize the residual voltage of the grounded fault phase to below 10 V, forcing reliable arc extinction at the grounded fault point, exhibiting good stability. Low-voltage simulation tests have also proved the feasibility of the algorithm.

Properties and microstructure characterisation of high-strength, high-conductivity and high-resistance to arc ablation Cu-0.6Te-0.3Cr-0.15Zr-0.008P alloy

In this paper, the intermetallic compound ZrTe2 phase is formed within a copper matrix by data-driven elemental screening. This low melting point ZrTe2 phase is uniformly and diffusely distributed within the copper matrix, which avoids the need for an energy-intensive process while providing superior resistance to arc ablation. On this basis, a novel Cu-0.6Te-0.3Cr-0.15Zr-0.008P alloy is designed and prepared, and the alloy achieves an electrical conductivity of 95.7 %IACS, a tensile strength of 302 MPa, and an elongation of 39.53% after the thermomechanical treatment. The ablation current of the novel alloy under large voltage is 31.2% lower than that of the Cu-0.6Te alloy, and the cross-sectional area of the ablation traces is reduced by 85%, which effectively illustrates the substantial improvement of the novel alloy's ability to resist arc ablation. There are ZrTe2 phases of 0.5–2 μm as well as pure Cr phases of about 5–20 nm in the alloy. The ZrTe2 phases absorbs heat through melting decomposition to achieve arc extinction, and the Cr phases pinning dislocations to promote strength enhancement. In addition, the synergistic addition of Cr and Zr plays a role in the grain refinement of the alloy, and the average size of the grains decreases from 4.2 μm to 3.1 μm, a decrease of 26%, under the same process. This novel CuTe alloy with high strength, high conductivity and high resistance to arc abrasion is easy to produce and low energy consumption, and is expected to be widely used in the new generation of high-voltage fast-charging electrical connector materials for new energy vehicles.

Theoretical and experimental studies on the self‐healing properties of metallised capacitor films under multiple stresses

AbstractMetallised film capacitors, for the most important merits is the excellent self‐healing property, have significant electrical insulation advantage. The essential factors affecting the self‐healing properties of metallised polypropylene film capacitors (MPPFCs) are first analysed, and a self‐healing performance characterisation test platform for metallised polypropylene capacitor films was built. Both the voltage/current waveforms and discharge patterns of the self‐healing process under multiple stresses including temperature, voltage and inter‐layer pressure were recorded and discussed. The correlation between self‐healing performance characterisation and the carbon that appeared on the surface of the dielectric layer during the arc extinction time is clarified. Finally, by virtue of an equivalent dynamic circuit model, the influence of square resistance and the equivalent capacitance of the power grid on self‐healing has been theoretically studied.

Methodology for Circuit Breaker Contact Diagnosis through Dynamic Resistance Measurements and Fuzzy-Logic-Based Analysis

This paper presents a methodology capable of measuring, processing, and extracting contact resistance parameters that enable the identification of the contact degradation level inside arc extinction chambers in medium- and high-voltage circuit breakers (CB). To determine the contact degradation level, an algorithm was developed to extract the characteristic parameters from the results of dynamic resistance measurement (DRM). To analyze the dataset parameters, this work employs the combination of different statistical tools, such as boxplots and fuzzy logic, enabling the evaluation to be conducted without the subjectivity inherent in human decision. Therefore, a more objective and reliable diagnosis could be achieved. The DRM tests were performed on two types of minimum-oil CB (MOCB), 800 A/15 kV/12.5 kA (CB-A) and 2000 A/72.5 kV/31.5 kA (CB-B and CB-C). For CB-A and CB-B, three contacts were utilized for each CB, with significant contact degradation. For CB-C, a single contact was employed without significant degradation. The DRM curves of the CB-C contact were used as the reference for evaluation of the CB-B contacts. For this purpose, a new DRM system was developed. The proposed methodology can be defined as a complement for other diagnostic techniques, serving as a non-subjective asset management tool, supporting decisions regarding equipment interventions.

Enhanced anti-welding and arc erosion performance of Ag-8 wt%SnO2 contact material with different addition of graphene nanoplatelets

To improve the welding resistance of Ag-8 wt%SnO2 contact material at large current, the graphene nanoplatelets (GNPs) was selected as the additive, and Ag-8 wt%SnO2 contact materials with different GNPs addition were prepared by powder metallurgy route. The electrical contact tests were performed under 36 V/16 A and 36 V/25 A, the welding, material transfer behavior and their mechanism were investigated combined with the analysis of arc duration, arc power and eroded morphology. The results show that 0.2 wt% GNPs addition decreases the welding frequency and welding force significantly, this can be attributed to the arc extinction effect and the weaken effect of the welding area. However, the excessive GNPs addition in turn aggravates the welding, the reason is that excessive GNPs addition weakens the bond between eroded layers, resulting in the decrease of arc stability and the generation of the small protrusion which cause the concentration of the contact stress and the electric field, which further results in the serious welding. Furthermore, 0.2 wt% GNPs addition decreases the mass loss rate, increasing the combination performance of Ag-8 wt%SnO2 contact material.

Extended Pantograph–Catenary Arc Modeling and an Analysis of the Vehicular-Grounding Electromagnetic Transients of Electric Multiple Units

As the operating speed of electric multiple units (EMUs) in high-speed railways increases, pantograph–catenary (PC) detachment arcing occurs frequently. The resulting vehicular-grounding electromagnetic transients are related to the dynamic characteristics of the arc length. During large detachment, the processes of arc extinction and arc reignition may occur, resulting in more severe train body (TB) over-voltages and adverse effects on some vehicular electronic devices. As an extension of the previous works, this paper aims to establish a suitable PC arc model to examine the TB transient voltages. To begin with, the arc length dynamic characteristics are reasonably analyzed to deduce the relationship between the detachment distance and the arc length via the chain arc model. Then, the dynamic characteristics of the arc length are introduced, and an arc modeling scheme is proposed to elaborate the vehicle-grid electric power model for EMUs encountering various arcing scenarios. Based on this, the transient over-voltages are analyzed, accounting for both the arc extinction and arc reignition, as well as the mutual influences of multiple detachments in a short time. The influential factors, including arc length characteristics, phase angle, excitation inductance, and grounding parameters, are also involved in the performed analyses.

Sulphur hexafluoride in modern medium-voltage switchgear: Advantages, hazards, and environmental impact

Sulphur hexafluoride is synthesised as a persistent and non-toxic gas with an exceptional dielectric strength. In contemporary medium-voltage switchgear within power distribution systems, SF6 gas is used for the insulation and the extinction of electric arc. The application of SF6 has advantages in terms of gas physicochemical characteristics and performance; the dimensions, the cost-effectiveness, the reliability of the switchgear equipment and the duration, as well as the cost of maintenance were significantly reduced. SF6 is a known greenhouse gas, which tends to accumulate in the lungs, inducing oxygen depletion and respiratory complications. The by-products of SF6 formed during the electric arc can be harmful and toxic. The equipment containing SF6 is being replaced in the EU and worldwide. Using ALOHA? software the scenarios of leakage for SF6 and by-products were modelled in urban areas, where the switchgear is frequently placed. In areas where the circulation of wind is lower (urban areas), in hazardous situations, it is not possible to depend on high dispersion levels or minimisation of concentration and threat. The models have shown that SF6 poses an environmental problem and its by-products cause a serious health hazard in the case of leakage in urban areas, rendering red threat zones from 10 to 60 m in radius.

Analysis and mitigation techniques of overvoltages due to insulator transient arcs clearing on a 500 kV OHTL

In high-voltage OHTL, Overvoltages and arc currents due to insulator transient arcs clearing severely affect the stability of power systems.In this paper, a 500 kV Egyptian OHTL was simulated using ATP-EMTP software package. The insulators transient arcs clearing of the system were tested under different impedances of tower footing, locations of insulator arc tower, angles at which the arc initiate. Additionally, the effects of the corona phenomenon were taken into account to achieve realistic study. Furthermore, these factors thoroughly were analyzed to determine worst-case scenarios. Also the paper evaluated the performance of the overvoltage mitigation methods based on the installation of neutral shunt reactors, MOSA (Metal Oxide Surge Arresters), or combinations of both.The results demonstrated that the combination of MOSA and neutral shunt reactors was the most effective mitigation technique, reducing overvoltages by approximately 57.4 %, arc currents by 80 %, and arc extinction time by 27.3 %Notably, the most severe overvoltages and peak arc currents occurred at an angle of θ = 180° and footing impedance 30Ω. Additionally, the corona phenomenon played a role in reducing the severity of overvoltages, arc currents, and arc extinction time by approximately 56 %, 56 %, and 1.8 %, respectively. Finally, These findings provide valuable recommendations for mitigating overvoltages, arc currents, and arc extinction time during insulator arc clearing events.

A novel strategy to improve melting efficiency and arc stability in underwater FCAW via contact tip air chamber

The conventional method of underwater flux-cored arc welding (UWW-FCAW) is characterized by water around the welding torch's electric parts, the tubular wire, the molten pool and the workpiece. In the present work, underwater FCAW was performed by keeping the contact tip dry, inside a specially developed torch, and as in conventional underwater welding. The welds were carried out in a flat position at simulated depths of 0.3 m, 10 m and 30 m using a hyperbaric chamber. Welding electrical signals of voltage and current and contact tip temperature were acquired and processed to determine process behavior. As a result, the welding current was reduced when the contact tip was kept dry inside the torch because of the higher temperature achieved by resistance heating when it was insulated from the water. The ambient surrounding the contact tip interfered with the coefficient of heat transfer and, consequently, with its temperature. Welds performed with the dry contact tip also presented slight variations in bead shape parameters in different water depths. Higher arc stability was achieved by welding with the contact tip inside the air chamber, as minor variations of electric signals and fewer arc extinction events were observed compared to conventional underwater welds. The combination of improved arc stability with higher electrode temperature may also have contributed to minor porosity and smaller variation of the reinforcement along the weld bead.

저압직류계통에서 유도성 부하의 차단아크 특성

This paper studies the characteristics of series arcs during the breaking operation of electric contacts of DC switches or socket outlet and plugs on inductive loads. Through experiments of DC series arc on inductive loads, arc extinction distance and arc transient voltage are analyzed and compared with pure resistive loads. This paper presents the arc-safe operation area according to the opening speed of electrode contacts and the time constants of various inductive loads in low-voltage DC(LVDC) systems.

Detection of secondary arc extinction and auto-reclosing in compensated AC transmission lines based on machine learning

Detecting and recognizing the secondary arc extinction is considered as a backbone of the single pole auto reclosing schemes. This paper proposes a multi-channel convolutional network to detect the secondary arc extinction during a long AC power transmission line arc fault. In contrast to the conventional methods, the proposed Machin learning-based method can automatically learn the features from the raw data given as input. Multivariate time series data of phase voltage, current and neutral reactor signals were used as the input to the proposed model. The features are extracted in the convolution layer instead of using hand-crafted feature extraction like most of the existing research. The softmax classifier is used to detect fault and secondary arc extinction. Matlab Simulink is used to simulate the test system and collect the dataset to evaluate the proposed neural network model. To verify the generalizability of the proposed architecture datasets were collected at various locations and different phase lines. The proposed algorithm was able to detect the secondary arc extinction with 98.26% accuracy and able to give signal for auto-recloser logic with the maximum window length of three cycles. The result shows that the proposed neural network architecture is accurate and robust to detect the secondary arc extinction further can be used as a signal for a single pole adaptive auto recloser scheme.

Adaptive single-phase auto-reclosing scheme based on the moving average filter-quadrature signal generator for transmission lines with shunt reactors

An adaptive single-phase auto-reclosing method based on the moving average filter (MAF)-quadrature signal generator (QSG) is developed to determine secondary arc extinction time for high-voltage transmission lines with shunt reactors. Firstly, the difference between permanent and transient faults is derived and analyzed by the equivalent circuit model. Then, MAF-QSG is utilized to extract these features from the fault voltage. During the second arc period, for transient fault, the fundamental component and subharmonic component with around 50 Hz are reserved by MAF-QSG; however, in the case of permanent fault, only the fundamental component is retained. Finally, the identification index and its threshold are designed above the extraction fault features. The performance of the proposed method is evaluated by simulation and field data studies, accounting for different transmission line compensation levels, transition resistances, and fault location conditions.

Mathematical Model of Pantograph Arc Based on Probability Distribution of Arc Parameters

Pantograph arc has become a potential hazard for the safe running of electric locomotive. It is essential to build an accurate mathematical model of pantograph arc for arc simulation. Pantograph arc experiments were carried out. And the probability distribution characteristics of arc parameters such as arc ignition moment, arc extinction moment and arc duration were analyzed. A mathematical model of pantograph arc was established. Firstly, Habedank model was selected as an initial mathematical model. The model parameters were optimized by using particle swarm optimization algorithm. Secondly, the initial mathematical model was preliminarily improved by using time-varying model parameters. Thirdly, taking into account the randomness of arc phenomenon, the model was further improved by adding a pulse function, and then the final mathematical model of pantograph arc was obtained. The pulse generation time and pulse width of the pulse function vary along with uniform distribution function and truncated normal distribution function, respectively. Finally, a simulation module of pantograph arc was designed with MATLAB software, and the effectiveness of the mathematical model was proved. The proposed model can describe the electrical characteristics of pantograph arc more accurately, and it can be used to further analyze the evolution of pantograph arc.

Experimental investigation on “glow flow” phenomenon during current-zero period between transverse magnetic contacts

The inter-electrode state of the transverse magnetic field contact during the current-zero period is determined by the evolution of the arcing process. It has an important effect on whether the vacuum switch can be successfully broken. In this paper, a series of contacts were subjected to arcing and fixed gap distance experiments. The results show that a special inter-electrode phenomenon (glow flow) appears during the current-zero period when the current exceeds the threshold for the transition from diffused to constricted state of the vacuum arc. The mechanism behind the formation of this phenomenon was elucidated through an analysis of multiple sets of experimental results. It is found that the inter-electrode phenomenon arises from the disruption of the equilibrium process between the pressure from the arc column plasma and the anode vapor flux on the near-anode side at the current-zero. The copper vapor falls and is ionized by collisions with heat-emitting electrons. The experimental results and theoretical analysis also show that this phenomenon has a time interval with the reignition phenomenon. When this phenomenon is intense to a certain degree, the reignition will occur with high probability. The observation and theoretical analysis results of this paper are relatively consistent with the research results of other scholars, which can help to improve the vacuum arc characteristics and interrupting mechanism. This can provide a basis for improving the arc extinction performance of the vacuum switch.

Research on the energy consumption mechanism and characteristics of the gallium indium tin liquid metal arcing process

For high-voltage direct current (HVDC) power grid transmission with higher voltages, the energy-consuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in the case of a fault and short circuit. The requirements for huge volume and weight are difficult to meet with energy-consuming equipment based on ZnO. In this paper, a new energy consumption method is proposed based on gallium indium tin (GaInSn) liquid metal in the arcing process, and a test platform with adjustable short-circuit current is built. The mechanism triggering GaInSn liquid metal arcing energy consumption is studied. It is found that short-circuit current and channel aperture are the key parameters affecting the energy consumption of liquid metal arcing. The characteristics of GaInSn liquid metal energy consumption are investigated, and four stages of liquid metal energy consumption are found: oscillatory shrinkage, arc breakdown, arc burning phase change and arc extinction. The influence of short-circuit current and channel aperture on the energy consumption characteristics of GaInSn liquid metal is investigated. To further explore the physical mechanism of the above phenomena, a magneto-hydrodynamic model of energy consumption in the GaInSn liquid metal arcing process is established. The influence of short-circuit current and channel aperture on the temperature distribution of the liquid metal arc is analyzed. The mechanism of the effect of short-circuit current and channel aperture on peak arc temperature and the temperature diffusion rate is clarified. The research results provide theoretical support for this new liquid metal energy consumption mode DC circuit breaker.

Effect of in-situ phase transition of (MgCoNiCuZn)O high-entropy oxides on microstructure and performance of Ag-based electrical contact materials

Reducing arc corrosion on the surface of electrical contact is beneficial for the stability of electrical systems. For improving the anti-arc erosion performance of composites, a reinforcement with good arc extinction and thermal stability is still a need. In this work, by annealing the as-prepared single-phase (MgCoNiCuZn)O high-entropy oxides (SHEO) reinforced Ag composites at 700 °C, the reinforcement was in-situ transformed in multi-phase (MgCoNiCuZn)O high-entropy oxides (MHEO) consisting of ZnCo2O4, CuO, and non-equiatomic (MgCoNiCuZn)O high-entropy oxides (NHEO). In this process, a semi-coherent interface is formed between CuO (firstly precipitated) and NHEO, and a coherent interface is formed between ZnCo2O4 (secondary precipitated) and NHEO. During arcing, the endothermic phase transformation from MHEO to SHEO reduced arc energy. A comparative study of the composites was carried out with 12 wt% reinforcement. Ag-MHEO possessed exceeded hardness than that of Ag-SnO2 and electrical conductivity similar to Ag-SnO2. Under the DC load of 24 V/8A, Ag-MHEO exhibited 60% less mass loss and 26% less burning arc energy than Ag-SnO2In2O3 during 10,000 times contacts. Compare with Ag-SHEO and Ag-SnO2In2O3, the arc corrosion on Ag-MHEO surface was the weakest after the mentioned contact. This study paves a feasible way to improve anti-arc erosion performance by in-situ reversible endothermic phase transformation.

A Method for Judging the Arc-Extinction Time of Resonant Grounding System Based on Frequence Difference

In the resonant grounding system, the accurate judgment of arc-extinction time has guiding significance for the line selection of grounding fault, the evaluation of the arc suppression effect, and the extraction and utilization of transient information after arc extinction. Aiming at the single-phase grounding fault of resonant grounding system, this paper analyzes the frequence change characteristics before and after arc extinction. It is found that the frequence of zero-sequence electrical quantity before arc extinction is power frequence, and it changes after arc extinction. It is used to construct single-frequence methods and dual-frequence methods for judging arc-extinction time. As a tool for dynamic frequence measurement, SOGI-FLL is utilized to realize the engineering application of the method for judging arc-extinction time. The method’s accuracy is proved by Matlab/Simulink simulation and field test.