Analysis of partial discharge activity at different temperatures through an heuristic algorithm (original) (raw)
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Iet Science Measurement & Technology, 2007
Numerical results are presented for the development of the post-streamer discharge stage in atmospheric pressure air. The model used comprises Poisson, charged-particle continuity and Navier-Stokes equations developed in two-dimensional cylindrical axisymmetric co-ordinates. Applied direct current voltage of 20% above the breakdown threshold is applied in a 1 mm gap between two parallel plate electrodes. Starting from a single electron as the initial condition, the transitory regime from the streamer to the glow discharge is analysed, and the glow discharge is shown to consist of the cathode fall, negative glow, positive column and anode regions. The positive column is shown to propagate in the form of a return wave towards the anode. The very fast redistribution of the electric field just after the streamer hits the cathode is presented. Furthermore, the current density at the cathode fall and anode regions is shown to increase and extend radially outwards, justifying the inclusion of a two-dimensional axisymmetric model to study the radial effects in the discharge. Neutral gas heating starts to occur with the initiation of the post-streamer discharge stage, and the neutral gas temperature increases at the cathode by approximately 180 K.
Characterization of the streamer regime in dielectric barrier discharges
Journal of Applied Physics, 2008
The streamer regime of a dielectric barrier discharge device is studied by performing a detailed statistical analysis of current-voltage measurements in air. A wide bandwidth Rogowski coil, designed to work down to the nanoseconds time scale, is used to record the discharge current. The temporal structure of the latter is identified and characterized by its probability density distribution as a function of the applied voltage. The results suggest the existence of two discharge regimes, separated by a well defined voltage threshold, reflecting the different behaviors of the microdischarges. The autocorrelations of the discharge signal are evaluated as a function of the applied voltage, indicating the presence of strong correlations at short-time scales ͑up to the order of 10 2 ns͒ and residual correlations at longer times. The latter are shown to be due to the nonstationarity of the discharge process.
Journal of Physics D-Applied Physics, 2011
In this work, a model representing partial discharge (PD) behaviour of a spherical cavity within a homogeneous dielectric material has been developed to study the influence of cavity surface charge distribution on the electric field distribution in both the cavity and the material itself. The charge accumulation on the cavity surface after a PD event and charge movement along the cavity wall under the influence of electric field magnitude and direction has been found to affect the electric field distribution in the whole cavity and in the material. This in turn affects the likelihood of any subsequent PD activity in the cavity and the whole sequence of PD events. The model parameters influencing cavity surface charge distribution can be readily identified; they are the cavity surface conductivity, the inception field and the extinction field. Comparison of measurement and simulation results has been undertaken to validate the model. © 2011 IOP Publishing Ltd. http://iopscience.iop.org/0022-3727/44/24/245202
Materials Today: Proceedings, 2019
An electrical model of Dielectric Barrier Discharge (DBD) is proposed to model the homogeneous and filamentary discharge. In the first part, for the homogeneous discharge, an equivalent circuit based on the electrical behaviour of DBD is studied. The discharge current and the gap voltage signals are given as a result of model simulation. The analysis of charge transfer has been carried out by means of Lissajous figures, and the dynamic of the discharge is depicted by the discharge characteristic. In the second part, for the filamentary discharge, the randomness of streamers breakdowns and the high frequency of the current pulses have been modelled based on a statistical study of breakdowns distribution. The results of the simulation for the two modes of discharge will be compared to the experimental outcomes.
Electrical model of an atmospheric pressure Townsend-like discharge (APTD)
The European Physical Journal Applied Physics, 2004
The aim of this paper is the modeling of a dielectric barrier discharge at atmospheric pressure, in the Townsend regime. This model is based on an equivalent electrical circuit. It takes into account the main physical phenomena of the discharge. This model allows to have a general view of the process and to study the influence of the power supply on the discharge. It is also an interesting tool for the power supply design and the process optimization.
Construction and test of a moving boundary model for negative streamer discharges
Starting from the minimal model for the electrically interacting densities of electrons and ions in negative streamer discharges, we derive a moving boundary approximation for the ionization fronts. Solutions of the moving boundary model have already been discussed, but the derivation of the model was postponed to the present paper. The key ingredient of the model is the boundary condition on the moving front. It is found to be of kinetic undercooling type, and the relation to other moving boundary models is discussed. Furthermore, the model is compared to two-dimensional simulations of the underlying density model. The results suggest that our moving boundary approximation adequately represents the essential dynamics of negative streamer fronts.
Transition from a Townsend discharge to a normal discharge via two-dimensional modeling
Physical Review E, 1994
The transition from a Townsend discharge to a normal discharge is investigated using a twodimensional numerical model and an approximate analysis. The numerical model is based on a fluid description of electron and ion transport coupled with Poisson s equation, with the ionization source depending on the local field strength or provided by a Monte Carlo simulation of the fast electrons. The model is applied to an argon discharge, for a product of pressure and gap length in the 1-10 Torrcm range. The proposed analytical model provides insight into the major physical phenomena observed experimentally in the subnormal glow region: the lateral constriction of the Townsend discharge with an increase of the current, the negative differential resistance of the discharge with a hysteresis loop in the current-voltage characteristics, and the appearance of current oscillations and their dependence on parameters of the external circuit. The field distortion is responsible for the constriction of the Townsend discharge provided that either the sign of the second derivative of the ionization coefficient a with respect to the electric field strength E is positive or the secondary emission coefficient y is an increasing function of E. A simple analytical description of nonlocal ionization is also suggested. Subnormal oscillations are treated as a two-dimensional phenomenon.
Modeling of a short (without positive column) glow discharge with active boundaries
Bulletin of the American Physical Society, 2013
Submitted for the DPP13 Meeting of The American Physical Society Modeling of a short (without positive column) glow discharge with active boundaries 1 ANATOLY KUDRYAVTSEV, KON-STANTIN BARZILOVICH, EUGENE BOGDANOV, St.Petersburg State University, VLADIMIR KOLOBOV, CFD Research Corporation, Huntsville, USA-As boundaries are very important in formation of nonlocal plasma properties, in this study a short dc discharge with cold cathode and application of different voltages to the conducting discharge wall has been simulated. The discharge model is based on a fluid description of ions and neutral species using drift-diffusion approximation for the particle flux. The description of electrons is based on a "hybrid" approach with subdivision for trapped and free (fast) electrons. Slow electron transport coefficients as well as electron induced reaction rates are determined from the solutions of the electron Boltzmann equation. The self-consistent electric field is calculated using the Poisson equation. 2D simulations for helium plasma at 1 Torr pressure confirm that the short glow discharge consists of cathode and anode sheaths of space charges, a cathode plasma negative glow, and a Faraday dark space. The plasma region characterized by low electron temperature and weak reversed electric field. It is demonstrated in the model that applied voltage can trap within the device volume energetic electrons arising from atomic and molecular processes in the plasma. It allows measurement of the fast part of the EDF by application of measuring wall electrode.