
Hao SUNState Key Lab of Electrical Insulation and Power Equipment · School of Electrical Engineering, Xi’an Jiaotong University
Hao SUN
Associate Professor
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91
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Introduction
Publications
Publications (91)
The cold-cathode plasma discharge switch is a switching device capable of conducting and interrupting currents. It has the potential to replace fully controllable power semiconductor devices in the field of direct current power transmission. The switch primarily consists of four electrodes: anode, control grid, source grid, and cathode. By applying...
Tianxiao Liu Hao SUN Gang Li- [...]
Yi Wu
C4F7N/N2 and C4F7N/CO2 gas mixtures are considered potential alternative gases to SF6, and it is of particular significance to investigate the plasma decay process in these mixtures for evaluating their circuit breaker breaking performance. To comprehend the decay process of electron density(ne) in arc plasma within C4F7N/N2 and C4F7N/CO2 gas mixtu...
Direct current (DC) circuit breakers are essential for maintaining the stability of the electric energy transmission and safeguarding the power equipment from the damage caused by the fault currents in DC power systems. The characteristics of the switching arc can be utilized in DC forced current zero techniques. This paper investigates the influen...
With the development of the direct current (DC) power grid, the research of the forced current zero techniques in DC circuit breakers is of vital importance. Through applying an external alternating transverse magnetic field to an air arc confined by insulating walls, the arc can oscillate in a specific pattern, which is defined as ‘magnetically co...
The SF6/N2 gas mixture mitigates the challenges associated with the use and liquefaction problems of pure SF6. It has great significance to analyze the decay characteristics of the plasma in it. Laser-induced plasma (LIP) and gas arc represent two distinct types of plasma, differing significantly in energy density and duration. This study utilized...
SF6 is a strong greenhouse gas with high liquefaction temperature, which limits its application in gas insulation equipment to a large extent. Therefore, the search for a replaceable gas has become a hot topic in electrical field. Although scholars have carried out a lot of research work on SF6 replacement gas, they have not yet found a gas that ca...
In modern power system, SF6 circuit breaker undertakes the important tasks of short circuit protection, switching control, and power distribution, which is an important factor to maintain the safe and stable operation of the system. The ablation caused by arc will shorten the electrical life and breaking performance of the contact system. Therefore...
With the development and promotion of arc theory and computer technology, arc simulation technology has become an important reference for product development and performance evaluation. Based on the theory of magnetohydrodynamics, an actual molded case circuit breaker model was simulated and studied. Considering the complex multi-physical field cou...
The gliding arc plasma is an effective way to convert CO2 into value-added products. In this paper, the promotion of CO2 conversion by the airflow field control and electromagnetic field control of gliding arc is studied. Firstly, the self-electromagnetic field control of gliding arc is studied through the change of current level or electrode spaci...
Investigating the post-arc dielectric strength recovery characteristics is essential for dc hybrid interruption, because a successful interruption in a hybrid dc switch is determined by the competition between the power system recovery voltage and post-arc dielectric strength recovery voltage. Based on a review of previous studies, related research...
Hao SUN Hu Long Yi Wu- [...]
Mingzhe Rong
SF6 gas is widely used on many occasions especially in the power equipment, but it has been restricted since Kyoto Protocol as the strongest greenhouse gas. To reduce the SF6 emission, several methods are now used such the recycling & purification and the SF6 degradation. Considering the huge market of SF6 and the recent demand in the field of powe...
Faced with increasingly severe environmental and energy issues, the development and utilization of solid waste have become a trend. In this study, a thermogravimetric-Fourier infrared spectrometer-mass spectrometer (TG-FTIR-MS) was used to carry out the co-pyrolysis experiment of coal slime and cellulose. The samples with mass mixing ratios of 0:10...
The effects of biomass on coal gangue combustion characteristics, combustion products and combustion reaction model are studied in this paper. Based on the thermogravimetric experimental data, a multi-component combustion reaction model for coal gangue and biomass was established. The CG combustion reaction mechanism can be well explained by the tw...
The development and utilization of solid waste is an effective way to solve the severe environmental and energy crisis. In this study, Thermogravimetry - Fourier transform infrared spectrometry (TG-FTIR) was used to carry out the co-combustion experiment of coal slime and rice husk under different mixing ratios. With the increase of the mass percen...
Carbon dioxide (CO2) and its mixtures are potential alternative gases for arc extinguishing in switchgear. During the arc decaying phase, the non-chemically equilibrium (non-CE) effect leads to the departure from the local thermal equilibrium (LTE) model in predicting the arc behavior. This work is focused on the dynamic behavior of CO2 arc during...
Faced with the problems of the environment and resources, the co-combustion of sewage sludge has gradually become a trend. In this paper, the combination of thermogravimetric and Fourier transform infrared spectroscopy (TG-FTIR) was used to study the co-combustion of sewage sludge (SS) and coffee industry residues (CIR). SS and CIR were mixed accor...
Magnetically confined cold-cathode plasmas in monatomic gases like helium can be used in a variety of devices and applications. In this paper, the radial distribution of electron temperature and electron density in cold-cathode helium plasmas constrained by an annular magnetic field were studied by optical emission spectroscopy. Helium plasma was g...
In this study, Thermogravimetric-Mass spectrometry-Fourier transform infrared spectrometry (TG-MS-FTIR) were used to study the co-pyrolysis behavior and gaseous products of coal slime (CS) and cattle manure (CM). By establishing different artificial neural network (ANN) prediction models, it was found that MLP13 model is the best prediction model....
The effects of lignin (LIG) on coal gangue (CG) pyrolysis characteristics, gas emissions, and multi-lump parallel reaction modeling are studied in this paper. The combined thermogravimetry and Fourier infrared spectrometer were used to obtain the weight loss and gas product functional group data of the co-pyrolysis of coal gangue and lignin. Gaussi...
In this study, thermogravimetry and Fourier transform infrared spectroscopy (TG-FTIR) were used to analyze the co-pyrolysis characteristics of coal slime (CS) and coffee industry residue (CIR) at different heating rates. The CS and CIR were mixed according to five mass ratios of 1:0, 7:3, 5:5, 3:7 and 0:1. Through the detection of gas emission and...
In this study, co-pyrolysis experiments were carried out by blending coal slime (CS) and traditional Chinese medicine residue (CMR) in different proportions under nitrogen atmosphere using thermogravimetry-Fourier infrared spectroscopy-mass spectrometry (TG-FTIR-MS). Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) were used to calculate t...
This study investigated the co-pyrolysis characteristics and kinetics of sewage sludge (SS) and wet waste (WW) using thermogravimetric-Fourier transform infrared spectrometry-gas chromatography/mass spectrometry (TG-FTIR-GC/MS) and artificial neural network (ANN). The proportion of WW is 0, 10, 30, 50, 70, and 100%, respectively. These mixtures wer...
In this work, we studied the influence of electrode materials and airflow area on CO2 conversion in gliding arc plasma. Herein, the correlation between breakdown events, including back-breakdown and re-ignition, and conversion rate was discussed. The experimental results show that the motion characteristics of the gliding arc when using different e...
Co-pyrolysis technology of urban solid waste and biomass has broad application prospects in alleviating energy crisis and environmental pollution. In this study, thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) was used to study the co-pyrolysis characteristics of coal gangue (CG) and coffee industry residue (CIR). CG and CIR wer...
Microparticles are an inevitable component of vacuum arcs. This paper focused on the dynamics of microparticle and erosion behavior in high-current vacuum arcs. The arc was sustained with AC 110 Hz between two butt CuCr alloy contacts with a diameter of 10 mm. An in situ microparticle diagnostic system suitable for vacuum arcs was developed. Three...
The pyrolysis experiment of biomass added to coal gangue was studied by thermogravimetric-Fourier transform infrared spectroscopy-mass spectrometry (TG-FTIR-MS) method. The multi-component reaction model was used to simulate the pyrolysis reaction of coal gangue and biomass. The most suitable model was obtained, and the pyrolysis mechanism was anal...
The on-load tap changer plays a very important role in the power grid. In high-voltage power transmission, a transformer loaded with an on-load tap-changer can adjust the voltage, improve the power quality, and adjust the load flow. However, there are few studies on the arcing characteristics of the oil medium involved in its switching process and...
In this paper, we focused on the influence of gas pressure on the dynamic characteristics of laser-induced plasma (LIP) in air. The energy-dependent transmittances of a 1064 nm laser to LIPs generated at the pressure of 0.2–5 atm were measured. Laser Rayleigh scattering and Thomson scattering methods were applied to investigate the evolution of las...
Based on the in situ diagnostic system and the digital image post-processing technique, quantifications of the anodic erosion components and heat transfer efficiency for tungsten and the W80Ag20 material in arcs of argon, helium, and nitrogen were achieved. The leading vaporization of silver has been found to result in evidently lower anodic heat t...
Thomson scattering was applied to measure the electron density and temperature in laser-induced SF 6 plasmas at various pressures (0.2 to 2 atm). The plasma was induced by the Nd: YAG laser (1064 nm, 200 mJ, 7 ns) focused into a chamber filled with SF 6. A second harmonic Nd: YAG laser (532 nm, 50 mJ, 6 ns) was used to probe the distributions of el...
Finding substitutes for sulfur hexafluoride (SF6), a gas with extremely high global warming potential, has been a persistent effort for years in the field of high voltage power equipment, which focuses on the evaluation of the electrical strength and boiling temperature for the practical purpose. Following up the previous proposed linear regression...
Arc plasmas have been extensively studied, experimentally and by means of modeling, due to their wide range of applications. In this article, a calibration-free Boltzmann plot method was applied to measure the species composition and pressure in the arc plasmas based on the assumption of local thermodynamic equilibrium and only single ionization of...
This research concentrates on the erosion mechanism of the W70Cu30 anode in DC gaseous arcs. An in-situ diagnostic system including the measurement of the anode surface temperature and the fast-imaging of the erosion process was developed. The influence of gas media, which were He, N2, H2 and Ar, and current, varying from 50A to 400A, was investiga...
Hao SUN Yifei Wu Yi Wu- [...]
Yanwei Nan
The calculation of critical electrical field, based on the balancing between the ionization and attachment of the electrons, has been widely used to obtain the dielectric breakdown strength of hot gas after arc burning. However, due to the negligence of electron drift, diffusion and photon ionization process and geometry of electrodes, this method...
Laser Thomson scattering and Rayleigh scattering methods were applied to investigate the dynamics of laser-induced plasmas in atmospheric air. Laser-induced plasma was generated by a 1064 nm, 200 mJ Nd: YAG laser. Another nanosecond Nd: YAG laser (532 nm, 50 mJ) was used as the probe laser. The temporally and spatially resolved electron number dens...
An experimental method for the air plasma composition based on two-color Mach–Zehnder interferometry was established. By applying two laser beams with different wavelengths, the distributions of the temperature and nonequilibrium parameter were obtained. In the arc center, the energy exchange between the electrons and heavy particles is sufficient...
The arc behaviors of different gas media, including air, N2 and O2, during the current-zero period in the circuit breaker were investigated based on a non-chemically equilibrium (non-CE) model. The arc behaviors during the decay phase by the non-CE model were compared with those by the local thermally equilibrium (LTE) model. In the LTE model, sinc...
Carbon dioxide ( CO 2 ) is a promising alternative to sulfur hexafluoride for high-voltage circuit breaker applications. It is important to have a detailed understanding of CO 2 arc properties. In this paper, radial temperature distribution of the free burning direct current arc in pure CO 2 was investigated. Optical emission spectrometry was appli...
The thermophysical properties, including composition, thermodynamic properties, transport coefficients and net emission coefficients, of thermal plasmas formed from pure iso-C4 perfluoronitrile C4F7N and C4F7N-CO2 mixtures are calculated for temperatures from 300 to 30 000 K and pressures from 0.1 to 20 atm. These gases have received much attention...
The influence of arc current and pressure on the non-chemical equilibrium (non-CE) air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the co...
The splashing erosion of electrodes in a DC atmospheric-pressure air arc has been investigated
by visualization of the electrode surface and the sputtered droplets, and tracking of the droplet
trajectories, using image processing techniques. A particle tracking velocimetry algorithm
has been introduced to measure the sputtering velocity distributio...
SF6-Cu mixture is frequently formed in high-voltage circuit breakers due to the electrode erosion and metal vapor diffusion. During the interruption process, the multiphase effect and deviation from local thermal equilibrium (non-LTE assumption) can both affect the thermo-physical of the arc plasma and further influence the performance of circuit b...
C5-PFK (C5-perfluoroketone, C5F10O) is under wide consideration as an environmentally-friendly alternative gas to SF6 in high-voltage applications, because of its superior insulation performance. The aim of this work is to study theoretically the arc extinguishing performance and electric strength of C5-PFK.
The arc extinguishing performance of C5-...
Dielectric properties of air plasma in a model circuit break were investigated. A chemically non-equilibrium (non-CE) model was used to simulate the arc dynamic behavior inside the nozzle during current zero period. Distribution of the critical breakdown electric field Ecr of hot air was derived from the electron energy distribution function by sol...
After current zero, which is the moment when the vacuum circuit breaker interrupts a vacuum arc, sheath development is the first process in the dielectric recovery process. An axial magnetic field (AMF) is widely used in the vacuum circuit breaker when the high-current vacuum arc is interrupted. Therefore, it is very important to study the influenc...
Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air-organic vapor mixtures were calculated based on the Gibbs free energy minimization. F...
Hantian Zhang Hao SUN F. Yang- [...]
T. Li
CO2 is a potential alternative for SF6 in the high voltage circuit breaker. In this paper, the critical re-duced electric field strength (E/N)cr of CO2, CO2-O2, CO2-N2, CO2-CH4 and CO2-H2 at different mixing ratios, pressures and temperatures (300~4000 K) have been calculated. The species composition of CO2 gas mixtures was calculated based on the...
The study of simulation aiming at the current-zero periods of plasma is significant for guiding the research and design of the circuit breaker, improving its switching capacity and understanding the development process of the current-zero periods of plasma. Since the development process of the current-zero periods of plasma is coupled with the coll...
The influence of the gas flow rate on the N2 arc behavior was investigated based on a previously established nonchemical equilibrium (non-CE) model. This numerical non-CE model was adopted in the N2 nozzle arc in a model circuit breaker. The arc behaviors of both the arc burning and arc decay phases were obtained at different gas flow rates in both...
As the first part of this series of papers, a new calculation method for composition and thermodynamic properties of 2-temperature plasma considering condensed species under local chemical equilibrium (LCE) and local phase equilibrium assumption is presented. The 2-T mass action law and chemical potential are used to determine the composition of mu...
The high-speed electromagnetic (EM) rail launcher has a wide range of applications. An inductive shunt device is usually paralleled with the rails of the launcher as an approach to limit the muzzle arc by transferring the extremely high armature current. The shunt parameters will significantly influence the rail current, armature velocity, and devi...
In this paper, the dielectric properties of CO2, CO2/air, CO2/O2, CO2/N2, CO2/CF4, CO2/CH4, CO2/He, CO2/H2, CO2/NH3 and CO2/CO were investigated based on the Boltzmann equation analysis, in which the reduced critical electric field strength (E/N)cr of the gases was derived from the calculated electron energy distribution function (EEDF) by solving...
A non-chemically equilibrium (non-CE) model was established to investigate the N2 arc plasma in the decaying phase during the arc interruption, and was validated by comparison with the experimental results based on laser Thomson scattering. Unlike the conventional model assuming the local thermodynamic equilibrium (LTE), in this non-CE model, the m...
Nitrogen gas has been investigated as one of the candidate substitutes for SF6 in a high-voltage circuit breaker (HVCB) and also in a low-voltage interrupter. In this paper, a chemically non-equilibrium model was established to investigate N2 arc plasmas in the decaying phase during current interruption in a model circuit breaker. Unlike the conven...