I am Ram , Ph.D. Student


Dear sir/madam,

I am trying to find out the correlation between the time delays in
conduction mechanism and the degree of earth resistance.

I am using PSPICE simulation package for the simulation work , any
suggestions to give help welcome



Research Title:

INVESTIGATION OF THE TRANSIENT BEHAVIOUR OF EARTHING SYSTEMS SUBJECTED TO
HIGH IMPULSE CURRENTS


One of the research objectives is to observe the correlation between the
time delays in conduction mechanism and the degree of earth resistance for
different soil resistivity, impulse polarity and earth electrode
configuration



Time delays can be defined as the time taken to reach the current peak.
Generally, the time delay can also be influenced by non-uniform water
settling process, drying and heating in soil and of course due to the
statistical nature of air breakdown. However, these influences are
neglected in determining the correlation between the time delays and earth
resistance reduction.
In the previous studies, the time delays in soil due to ionisation and
heating have been plotted against current/voltage magnitudes. It was found
that the time delays were decreasing with higher currents/voltages.
However, the tune delays were also taught to be due to a statistical
nature of air breakdown.

If you have any question welcome

I am looking forward to hear from you soon

Thanks in advance

Ram

[speculative input]

It seems that channels of higher conductivity in a low conductivity
matrix would lead to longer times to peak I in that there would be
fewer parallel current paths, and consequently, higher effective
inductance in the path.

Brian Whatcott Altus OK

On 29 Jul 2004 01:47:09 -0700,
) wrote:

I am Ram , Ph.D. Student


Dear sir/madam,

I am trying to find out the correlation between the time delays in
conduction mechanism and the degree of earth resistance.

I am using PSPICE simulation package for the simulation work , any
suggestions to give help welcome



Research Title:

INVESTIGATION OF THE TRANSIENT BEHAVIOUR OF EARTHING SYSTEMS SUBJECTED TO
HIGH IMPULSE CURRENTS


One of the research objectives is to observe the correlation between the
time delays in conduction mechanism and the degree of earth resistance for
different soil resistivity, impulse polarity and earth electrode
configuration



Time delays can be defined as the time taken to reach the current peak.
Generally, the time delay can also be influenced by non-uniform water
settling process, drying and heating in soil and of course due to the
statistical nature of air breakdown. However, these influences are
neglected in determining the correlation between the time delays and earth
resistance reduction.
In the previous studies, the time delays in soil due to ionisation and
heating have been plotted against current/voltage magnitudes. It was found
that the time delays were decreasing with higher currents/voltages.
However, the tune delays were also taught to be due to a statistical
nature of air breakdown.

If you have any question welcome

I am looking forward to hear from you soon

Thanks in advance

Ram

Time-related transients in systems of conductors are more accurately
analysed by considering the conductors to be transmission lines. Propagation
velocity and characteristic impedance are essential features to be
approximated. Reflections are also important factors.

Applies equally to lightning conductors.

Now carry on with your thesis.
----
Reg Edwards.

"Reg Edwards" wrote in message
...
Time-related transients in systems of conductors are more accurately
analysed by considering the conductors to be transmission lines.
Propagation
velocity and characteristic impedance are essential features to be
approximated. Reflections are also important factors.

Applies equally to lightning conductors.

Now carry on with your thesis.
----
Reg Edwards.

Reg, I think he might be referring to the transfer-times from a conductor to
different components of soil. Not the transmission line theory inside a
conductor. The reaction speed of ground systems are under a lot of study to
help determine the best control of ground potential rise (GPR) where
isolation by fiber optic or HV isolation transformers alone is insufficient
protection.

Water/wet soil along the soil surface during a strike attachment makes it
hard to control GPR when it connects multiple earthing points almost
instantaneously. The dry-ground sections of each earthing rod end up making
less contribution to the designed voltage division, and increased current
from grounding systems up into the interior of buildings is one result.
It's an interesting problem creates and conflicts between design approaches
for lightning protection. What works for direct attachment will not work for
the near-field, in other words.

Best regards

Jack Painter
Virginia Beach VA

Time delays seems to infer the involvement of some capacitance into the mix
between 2 points of earth ground.

the time delays infer a breakdown in insulation when the voltage builds
sufficiently up to the insulation breakdown point.

So find the breakdown voltage of the insulation and the capacitance and the
applied voltage and the resistance, and you may be able to predict a time
delay.

- I may be wrong - but that's my 2-cents
Hal



wrote in message
om...
I am Ram , Ph.D. Student


Dear sir/madam,

I am trying to find out the correlation between the time delays in
conduction mechanism and the degree of earth resistance.

I am using PSPICE simulation package for the simulation work , any
suggestions to give help welcome



Research Title:

INVESTIGATION OF THE TRANSIENT BEHAVIOUR OF EARTHING SYSTEMS SUBJECTED TO
HIGH IMPULSE CURRENTS


One of the research objectives is to observe the correlation between the
time delays in conduction mechanism and the degree of earth resistance for
different soil resistivity, impulse polarity and earth electrode
configuration



Time delays can be defined as the time taken to reach the current peak.
Generally, the time delay can also be influenced by non-uniform water
settling process, drying and heating in soil and of course due to the
statistical nature of air breakdown. However, these influences are
neglected in determining the correlation between the time delays and earth
resistance reduction.
In the previous studies, the time delays in soil due to ionisation and
heating have been plotted against current/voltage magnitudes. It was found
that the time delays were decreasing with higher currents/voltages.
However, the tune delays were also taught to be due to a statistical
nature of air breakdown.

If you have any question welcome

I am looking forward to hear from you soon

Thanks in advance

Ram


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