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Why umbrella? is it
because the high voltage transmission lines are protected against the bad
weather by huge umbrellas?
No, of course! |
In
fact this site deals with the way the short circuits are detected on the high
voltage overhead lines. What more simple? You have in your house, as
everybody, a circuit breaker which trips thanks to overcurrent detectors
if, when you are tinkering on your electric installation, you make
wires touch together, ore if a wire in your washing machine touch the tin, or
if you install too many electric apparatuses. We have only to do the same on
the high voltage lines. After all, it is always electricity! |
Not so simple! Firstly the voltages and
currents of the described lines are much higher than in your house: up to 400
000 V and 4 000 A, versus 220 V and 30 A (or a little more if you have an
electric heating) in your home. So it is no more possible to make the
detectors work with such data, but you must use reducers giving of them an
image as accurate as possible, but with a reduced scale.
Then, as there is in your house only one
wire which comes in and another which comes out, on the high voltage lines
there are three wires, or three bundles of wires, run by different voltages.
More, when in your home the energy comes always from the outside, it may flow
here indifferently in one sense ore in another, depending on the mood of the
great sorcerers which manage the network. Finally the people who operate the
circuit breakers cannot see what happends on the line, and must however avoid
accidents |
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All
this leeds to develop some equipment, rather complicated to design, to
manufacture, to install and to set. It must even be created, to set a number
of them, a program named Umbrella.
This is the translation of a french sigle, but I like it as I like to walk
under an umbrella
when it rains. You not? So each time you see the word Umbrella written, or
you see a drawing or a picture with an umbrella, click on it
and you will change your opinion. |
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And this sigle
means "Programme d'Aide
au Réglage des Appareils de Protections
de Ligne Utilisant l'Impédance Electrique" (program to help the setting of the line
protective relays using electrical impedance) |
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This is a program
reckoning the setting of equipment situated on each end of the electric
energy transmission lines,
...
otherwise, of the high voltage overhead lines which
embellish the landscape of our beautifull country;
these
devices make trip the circuit breakers placed on each end of these lines,
when a short circuit due to lightning or else, disturb them. |
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Is this quite clear for
you ? Probably not, and that is why I put on this website a book
explaining how the disturbances of all kind likely to appear on the french
network are cleared Why the
french network? Simply because it is the one I know the best. But each time I
could, I noticed how other networks are protected. |
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(the transmission network is the whole
of overhead lines, underground cables and power transformers having in charge
the transmission of electrical energy from the power plants to the
20 000 V networks. These assets work at voltages from 63 000 V to 400 000 V on the french
network, and even 730 000 V on other countries, |
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If all this does not
interess you, so good bye and
thank you for your visit. |
If you are interested,
here are the documents you will find : Ì Book" protection and
monitoring of the transmission network"
(this document contains
among others the presentation of the program umbrella in appendix 8, and its
guidebook in appendix 9) Ì Program Umbrella If you want more
explanations, contact me at: * mailto:michel.lami@numericable.fr
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If you do not find the further documentation, send me
a mail to the address michel.lami@numericable.fr., with your own post address.
I shall send you a CD with the whole documentation.
I created this website in a total unpaid way.
If you want to gratify me, you can make a gift to
the association
SOS méditerranée
Thank you for them!