LIGHTNING PROTECTION USING LFA-M PDF

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WELCOME LIGHTNING PROTECTION USING LFA-M Submitted By:Somi.P. Chacko Class: S7-EEE Roll no: MCET CONTENTS. Presentation on theme: “LIGHTENING PROTECTION USING LFA-M”— System ”-A system of lightning protection conductors lightning rods -installed on the. effective and inexpensive method for lightning protection of medium voltage overhead distribution line is using long flashover arresters (LFA).

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For the protection of lines against direct lightning strokes, the arresters are connected between the poles and all of the phase conductors in parallel with the insulators.

There are three clouds P,Q and R having positive, negative and positive charge respectively. The effect of the power frequency voltage of a kV line on discharge process protevtion the arrester surface is negligible.

LIGHTNING PROTECTION USING LFA-M

Thus, the number of outages caused by direct lightning strokes can be lowered with the use of LFA arresters by an order of magnitude or more even for high values of grounding resistance. From the line, current path may be over at the ground. Electricity The movement of charge from progection place to another Requires energy to move the charge Also requires conductors. When the potential between the cloud and line exceed the breakdown value of air, the lightning discharge occurs between the cloud and the line.

How lightning is formed. Semiconductive core of upper piece, whose resistance is R ,applies the high potential U to the surface of the lower piece at its middle. Topics For Seminar Back to the top.

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LIGHTENING PROTECTION USING LFA-M

Extend the working life of high voltage circuit breakers. When the potential between the cloud and line exceed the breakdown value of air, the lightning discharge occurs between the cloud and the line. The important feature of this modular long flashover arrester LFA-M is that it can be applied for lightning protection of overhead distribution line against both induced overvoltages and direct lightning strokes.

When the modules increases the total arrester stressing is distributed these modules also. It follows from the previously described sequence of events that direct lightning stroke causes flashover of all the insulators on the affected pole.

The equivalent EMF e is calculated lfam follows. The lfz-m pieces are arranged so as to form three flashover modules 1,2,3 as shown in figure1. Furthermore, the arresters and insulators are checked for flashover based on their voltage-time characteristics. A single LFA per support or pole is found to be sufficient to protect an over head line against induced over voltages.

It offers great number of technical and economical advantages. You do not have the permission to view this presentation. It is shown that the steepness and not the magnitude of lightning current I l l I l is the important factor in the performance if a LFA protected line thus 1 can be written in the following form.

LIGHTNING PROTECTION USING LFA-M

The over voltage set up due to the stroke may be large enough to flashover this path directly to the ground. OK Rate of libhtning of electrical charge is called current P2 4. The usihg stroke can be of two types. The induced overvoltages can be counteracted by installing a single arrester on an overhead line support pole.

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The result is that charge on cloud R suddenly become free and it then discharges rapidly to earth, ignoring tall object.

Lihtning stroke result from eletrostatically induced charges on the conductors due to the presence of charged cloud. Both results put an. Therefore, the nearest pole is not to be taken into account in the coordination analysis of the LFA A. At instants t 4t 5and t 6 the first, third, and second modules of arrester LFA B flash over, respectively, changing the resistance of the arrester.

First, a lightning impulse causes a spark over of the spark gaps Next, the semiconducting core of the upper cable piece, whose resistancecarries the high potential to the surface of the lower piece at its middle.

The important feature of this modular long flashover arrester LFA-M is that it can be applied for lightning protection of overhead distribution line against both induced over voltage and direct lightning strokes. The presentation is successfully added In Your Favorites.

The voltage causes the insulator to flashover. The general pattern is as follows. The rate of channel propagation on arrester modules is determined, and the. If a positively charged cloud is above the line and induces a negative charge on the line by electrostatic induction.

Devices which pgotection the high voltage sparks resulting out of lightening. Go to Application Have a question?