Analysis of partial discharge activity at different temperatures through an heuristic algorithm (original) (raw)
A Comparative Study of Time-Evolution Characteristics of Single and Double Cavity Partial Discharges
Energies, 2024
Partial discharge (PD) in cavities can lead to a breakdown in solid insulation and, therefore, indicate the onset of aging in electrical equipment. It is necessary to investigate the activity of singleand double-cavity PD under aging conditions, which is the focus of this study. The results obtained can be useful in monitoring the condition of insulation systems. The factors (pressure, effective work function, and charge decay time constant) that influence PD behaviour under different test conditions were permutated in a PD model. The simulation results agree with measurements obtained for the same applied voltage. The model can generate PD pulse distribution shapes similar to the measured PD of single and double cavities. Both turtle-like and rabbit-ear-like phase-resolved PD (PRPD) patterns were observed during the aging process of the samples in both double and single cavities. This study concludes that the identification of the PD pattern achieved in this work for closely coupled cavities is a step towards characterizing multiple defects phenomena through PD evolution patterns.
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.
On the accuracy and reliability of different fluid models of the direct current glow discharge
Physics of Plasmas, 2012
We developed and tested 2D "extended fluid model" of a dc glow discharge using COMSOL MULTIPHYSICS software and implemented two different approaches. First, assembling the model from COMSOL's general form pde's and, second, using COMSOL's built-in Plasma Module. The discharge models are based on the fluid description of ions and excited neutral species and use driftdiffusion approximation for the particle fluxes. The electron transport as well as the rates of electron-induced plasma-chemical reactions are calculated using the Boltzmann equation for the EEDF and corresponding collision cross-sections. The self-consistent electric field is calculated from the Poisson equation. Basic discharge plasma properties such as current-voltage characteristics and electron and ion spatial density distributions as well as electron temperature and electric field profiles were studied. While the solutions obtained by two different COMSOL models are essentially identical, the discrepancy between COMSOL and CFD-ACEþ model solutions is about several percents and caused by the difference in the models due to undocumented details in the software packages. We also studied spatial distributions of particle fluxes in discharge plasma and identified the existence of vortex component of the discharge current. V
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.