Properties Of Corona Discharge Research Articles

Optimization Objective Function Corona Discharge Acoustic Using Fuzzy c-Means (FcM )

In many electrical networks in Indonesia, insulation failure due to high voltage phenomena like Corona Discharge (CD) still happens. This is a result of our inability to perform early Corona Discharge (CD) identification. This study’s objective is to optimalize the sound properties of Corona Discharge (CD) as a first step throught the early identification of insulation failure in the form of clustering 20 kV cubicle. Based on observations on the needle-rod electrode 3 cm apart, the smallest breakdown was obtained at 34.3 kV. So that the classification of CD sound by 3 clusters starting 20 kV cubicle voltage until before the failure occurs on 33 kV. The temperature in the cubical is between 27.5℃ - 35.3℃ and humidity ranges from 70% - 95%. It was stated in the study that the FcM method was the most widely used and successful method. In this case, FcM can obtain more flexible results that classify data into clusters easily. This research will be carried out using the Fuzzy c-Means (FcM) method. Feature extraction with linear predictive coding (LPC) method, then optimization by using the Fuzzy c-Means (FcM) method which is expected to be used as an initial step for early detection of insulation failure.

The Effect of Environmental Temperature on Negative Corona Discharge Under the Action of Photoionization

The properties of corona discharge in practical applications are strongly influenced by the variation of environmental parameters. A 2-D axisymmetric hydrodynamic drift-diffusion model coupled with Poisson's equation and three Helmholtz differential equations is established to investigate the effect of environmental temperature on negative corona discharge under the action of photoionization. This numerical model is performed by a traditional needle-to-plane configuration in dry air at atmospheric pressure. The characteristics of Trichel pulses, negative ion density, electric field, and electron density are discussed in this paper. It is found that the magnitude of Trichel pulses, first pulse duration, and pulse frequency increase with increasing the ambient temperature. Moreover, the effect of photoionization under these conditions is also investigated by simulations intensively.

Properties of corona discharge plasma near metal surface

Properties of corona discharge near metallic surface were researched. Electrical oscillations in discharge plasma of 1 kHz - 100 MHz rate were registered. Spectrum of electrical oscillations in this range was obtained. Possible plasma waves for observed electronic oscillations explanation are discussed.

Monte Carlo simulation of positive corona discharge in SF6

Gas-insulated systems are now a major component of power transmission and distribution systems all over the world. There has been considerable interest in non-thermal discharges over the past decade due to the increased number of industrial applications. Diverse applications demand a solid physical and chemical understanding of the operational principals of such discharges. This paper focuses on the most important and widely used variety of non-thermal discharges, the corona discharge. Positive corona in SF6 is studied for a point to plane electrode gap using Monte Carlo simulation technique. The initiation and development of successive avalanches are traced as function of time. The simulation provides a detailed structure of avalanches from which essential properties of corona discharge with regard to total field distribution, propagation of successive avalanches and ion distribution can be discerned.

Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

Electric discharge excimer lasers are sustained in multi-atmosphere attaching gas mixtures that are typically preionized to enable a reproducible, uniform glow, which maximizes optical quality and gain. This preionization is often accomplished using UV light produced by a corona discharge within the plasma cavity. To quantify the relationship between corona discharge properties and those of the laser discharge, the triggering of electron avalanche by preionizing UV light in an electric discharge-pumped ArF* excimer laser was numerically investigated using a two-dimensional model. The preionizing UV fluxes were generated by a corona-bar discharge driven by the same voltage pulse as the main discharge sustained in a multi-atmospheric Ne/Ar/Xe/F2 gas mixture. The resulting peak photo-electron density in the inter-electrode spacing is around 108 cm−3, and its distribution is biased toward the UV source. The preionization density increases with increasing dielectric constant and capacitance of the corona bar. The symmetry and uniformity of the discharge are, however, improved significantly once the main avalanche develops. In addition to bulk electron impact ionization, the ionization generated by sheath accelerated secondary electrons was found to be important in sustaining the discharge current at experimentally observed values. At peak current, the magnitude of the ionization by sheath accelerated electrons is comparable to that from bulk electron impact in the vicinity of the cathode.

Numerical simulation of positive corona discharge in air

Electrical discharges play a key role in technologies, the corona discharge commonly occurs in many engineering devices and processes. Diverse applications demand a solid physical and chemical understanding of the operational principals of such discharges. All of this reflects on the great importance of the evaluation of the corona performance characteristics. Numerical simulation of the corona discharge is necessary for predicting the performance of a device. The present work is devoted to the numerical determination of the properties of corona discharge in a DC positive point-to-plane gap in air. The inception and propagation of the avalanche is simulated by Monte Carlo method. This method provides the spatial-temporal local field and charge density variations as well as the avalanche front velocity.

MONTE CARLO SIMULATION OF POSITIVE CORONA DISCHARGE IN NITROGEN

The corona discharge commonly occurs in many engineering devices and processes. Their application is still largely based on empirical knowledge; accordingly it is very important to predict the physical properties of corona discharge by the appropriate numerical method. To control corona discharge properly by understanding of corona discharge properties at different discharge stages, time-varying characteristics of discharge which are resulted from electron collision with the gas molecules should be investigated. A numerical study of a corona discharge in nitrogen in a point to plane geometry is presented. It is obtained by Monte Carlo method and concerns space-time evolution of electron and ion densities as well as electric field distributions along the discharge axis.

Optical studies of the plasma-liquid transition layer in pulsed corona discharges in strong water electrolytes

The properties of corona discharge in strong water electrolytes are studied experimentally. An analysis of the measured time-integrated spectrum of the corona plasma emission shows the presence of a thin vapor layer between the plasma and liquid. The time dependences of the layer thickness are derived from the discharge shadowgraphs. The role of the transition layer in the energy conversion process in a corona discharge in strong electrolytes is determined.

Density profiles of corona discharge plasmas

Corona discharge properties in the reactor chamber are investigated, assuming that a specified voltage profile V( t) is fed through the inner conductor. The analytical description is based on the electron moment equation. Defining the plasma breakdown parameter u = V R c p , plasma is generated for a high voltage pulse satisfying u > u c, where u c is the critical breakdown parameter defined by the geometrical configuration. Here, u is in units of a million volts per m per atm, and R c is the outer conductor radius. It is found that the plasma density profile generated inside the reactor chamber depends very sensitively on the system parameters. A small change of a physical parameter can easily lead to a density change of one order of magnitude.

An analytical theory of corona discharge plasmas

In this paper we describe an analytical investigation of corona discharge systems. Electrical charge and the energy transfer mechanism are investigated based on the circuit analysis. Efficient delivery of electrical energy from the external circuit to the reactor chamber is a major issue in design studies. The optimum condition obtained in this paper ensures 100% energy transfer. Second-order coupled differential equations are numerically solved. All the analytical results agree remarkably well with numerical data. The reactor capacitor plays a pivotal role in circuit performance. The voltage profile is dominated by the reactor capacitor. Corona discharge properties in the reactor chamber are also investigated, assuming that a specified voltage profile V(t) is fed through the inner conductor. The analytical description is based on the electron moment equation. Defining the plasma breakdown parameter u=V/Rcp, plasma is generated for a high-voltage pulse satisfying u>uc, where uc is the critical breakdown parameter defined by geometrical configuration. Here, u is in units of a million volts per m per atm, and Rc is the outer conductor radius. It is found that the plasma density profile generated inside the reactor chamber depends very sensitively on the system parameters. A small change of a physical parameter can easily lead to a density change in one order of magnitude.

A study of the electrostatic behavior of carpets containing conductive yarns

This paper describes experiments to characterize the role of triboelectric charging in developing static charge as people walk on carpets and further experiments to quantify the role of corona ionization to minimize static charge accumulation. The Modified Inclined Plane test, a test currently gaining acceptance in the electronics industry, was used to measure triboelectric charging effects. Results indicate that this test was not a good predictor of static charge accumulation as measured by the body voltage on a person after a standard walk test. A test was developed to measure the effectiveness of corona discharge ionization caused by conductive filaments in carpet for limiting static charge accumulation. Results of this test have shown that, for carpets with good static charge dissipation properties, charge reduction via corona occurs on a time scale of about 0.1 s and that conductive latex greatly enhances the corona effect. Another test was developed to investigate the corona discharge properties of the conductive yarns themselves, without being incorporated into the carpet. Results of this test have shown that the corona voltage to initiate corona discharge depends largely on conductive fiber geometry and, that the conductivity vs. applied across the series combination of conductive yarn and air gap deviates significantly from Ohm's law behavior.