Corona stabilization and electrical breakdown of gases in no uniform fields

Other Title(s)

استقراريه الهالة و الانهيار الكهربائي للغازات في المجالات غير المنتظمة

Dissertant

Muhammad, Hasan Jasim

Thesis advisor

Hassani, Abd al-Rida Salman

Comitee Members

Salih, Haydar A.
al-Birmani, Muhammad Jafar Fadil
Amin, Hamid Mahmud
al-Wattar, Abbas Jasim Hammadi
al-Hamdani, Kazim Abd al-Wahid Adam

University

University of Baghdad

Faculty

College of Science

Department

Department of Physics

University Country

Iraq

Degree

Ph.D.

Degree Date

2013

English Abstract

High –pressure dc corona discharge experiments have been carried out in a 16cm long Pyrex chamber with an inner diameter 16.8cm , and 19cm outer diameter .

Corona onset and breakdown voltages were reached.

The design considerations of the setup allow to use different types of electrode geometries.

Various gases such as air ,Freon(R22) ,SF6, and SF6/Freon mixtures, were separately used for low temperature corona generation.

The experiments have been carried out under ambient Laboratory conditions of temperature, and humidity .

The present experiments were performed under applied voltages of up to (110kV), and operational gas pressure between (1bar and 3bar).

These pressure values allow to operate the chamber with a sparking parameter (Pd) ranging from (1bar.mm to 15bar.mm).

Moreover, corona stabilization mechanism and subsequent regions were investigated in the above gases under their corresponding voltage values ,for six electrode geometries (brush-plane , saw-tooth –plane, multipin-plane, pin- to-pin, needle–plane, and point(diameter 0.5,1,2,2.5,3,and 5mm)-to-plane ).

Stressed by a highly nonuniform electric fields were fitted into the test chamber and corona stabilization and breakdown parameters were recorded and fully analyzed for an electrode spacing between (1mm and 5mm) Corona current pulses have been recorded over the course of these experiments with current values ranging from (2μA to 325 μA).

The VI optimum corona current values were recorded in brush to plane electrode geometry by having a current exceeding (325μA).

Corona pulses of current exceeding (325μA) corresponding to an applied voltage of (105 kV) for SF6 were recorded.

On the other hand, corona pulses of current of up to (105μA ) corresponding to an applied voltage of (73kV) for Freon were delivered.

For SF6/Freon mixtures the corona current exceeded (250 μA) with an applied voltage of (88 kV ).

It has been found that the corona stabilization process in SF6 is governed by a number of parameters including gas pressure (2 - 2.5bar), electrode tip curvatures (2 - 3 mm ), and electrode spacing (2 -4mm).

Such effect leads to a profound behavior of the (V-P) and (V-d) characteristic curves of the gas.

Corona stabilization disappears in diameter of (5mm) for point to plane electrode under the above conditions.

Under certain experimental conditions involving particular values of sparking parameters, results demonstrated a well-defined region on the right hand side of Paschen's curve governed by the streamer process.

Main Subjects

Physics

No. of Pages

133

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-607714