Abstract
What is the effect of Corona in the power system?
What is the Corona formation theory?
What are the factors and conditions affecting corona?
What is Corona energy loss?
What are the Ways to reduce the effect of corona?
What are the advantages and disadvantages of the effect of
corona?
All of these
questions will be answered during this research with the content of each of
them as possible.
Introduction and Research Objectives
In
this research, I will review a widely spread phenomenon, which is the coronal
phenomenon, and we will know that it produces the result of ionization of the
air surrounding the energy system, and it has several indications of it, such
as the presence of purple light around the conductor and the occurrence of a
hissing sound
It
has a group of factors that affect it, such as the atmosphere, the conductor
size, the distance between the conductors, humidity, and line voltage. All of
these are factors that we will review in detail in the research
Also,
we will know methods to reduce this phenomenon, such as increasing the distance
between conductors, increasing the area of the conductor section, or by using
bundled conductors
We
will know what are the advantages and disadvantages
Although
its faults are many, it has some advantages, such as the increased diameter
reduces the electrostatic pressure between the conductors and the ozone
industry.
What is the
effect of Corona in power system?
When alternating voltage difference is applied across two
conductors whose spacing is large compared to their diameters, there is no
visible change in the condition of the air atmosphere surrounding the wires if
the applied voltage is low.
However,
when the applied voltage exceeds a certain value, called the critical Vandal
voltage, the conductors are surrounded by a faded purple flare called a corona.
Coronal
phenomena are accompanied by hissing, ozone production, energy loss, and radio
interference.
The higher
the voltage, the greater the size of the luminous shell, and the greater the
sound, power loss, and radio noise. If the applied voltage is increased to the
breakdown value, then flashing between the conductors will occur due to the
breakdown of the air insulation.
[1]
The effect of corona or corona discharge
on transmission lines and power system
can be defined as follows:
The phenomenon
of purple glow, hissing noise, and ozone production in the upper transmission
line is known as the corona.
v Corona
formation theory
Some ionization
is always present in the air due to cosmic rays, ultraviolet radiation and
radioactivity. Therefore, under normal circumstances, the air surrounding the
conductors contains some ionizing particles (i.e. free electrons and + ions)
and neutral particles.
When applying
p.d. Between conductors, a possible gradient in the air is assigned which will
have a maximum value on the conductor surfaces. Under the influence of a
possible gradient, existing free electrons gain faster speeds. The higher the
applied voltage, the greater the potential gradient and the faster the free
electrons.
When the
potential gradient on the surface of the conductor reaches about 30 kV per cm
(maximum value), the speed that free electrons obtain is sufficient to multiply
a neutral molecule with enough force to remove one or more electrons from it.
This produces
another ion and one or more free electrons, which are accelerated to collide
with other neutral molecules, thus producing other ions. Thus, the ionization
process is cumulative. The result of this ionization is that a corona or spark
is formed between the conductors
تعليقات
إرسال تعليق