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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This has 3 main parts. To make this website work, we log user lightniny and share it with processors. In this design, the total arrester stressing voltage is applied simultaneously to all of the three modules so that the voltage-time characteristics of the arresters are improved.
Click To Add Llghtning. Lightning is a huge spark and that take place when clouds are charged to at a high potential with respect to earth object e. Therefore the total voltage U is applied to each flashover module at the same moment, and all three modules are assured conditions for simultaneous initiation of creeping discharges developing in to a single long flashover channel.
An LFA mounted on the top phase must flash over before the top phase insulator. Thank you for providing the great information on a Lightning Protection System The pictorial representation is very helpful for every new user. This is the reason why the calculation takes into account the critical values of the lightning current steepness I l l ,cr at which the insulator flashes over for a given set of parameters. Where N DLS is the number of direct lightning stroke DLS on a line; P I l is the probability of lightning current likely to cause flashovers of the line insulation; P arc is the probability of a power are caused by an impulse flashover an insulator; and P rc is the probability of successful line breakers enclosures.
From the line, current path may be over at the ground. It is seen from Fig. Edirisinghe T Department ptotection EE. It is designated as LFA-M. A heavy impulse current flows through the flashover channel, the pole, and the pole footing resistance resulting into a large sharp voltage rise at the cross-arm. There are three clouds P,Q and R having positive, negative and positive charge respectively.
Where k is the outage reduction factor of lightning outages caused by direct lightning strokes. Labels Seminar Topics 3 Welcome 1. Flashover of insulator Ins A indicates lightning protection failure. Lightning is an electrical discharge between cloud and the earth, between clouds or between the charge centers of the same cloud.
Long Flashover Arrester (LFA) Seminar Report
It offers a great number of technical and economic advantages. Protect electric networks against arc over voltages. Nice seminar on Lightning Protection. Its resistors assure application of the total arrestor-stressing voltage simultaneously to all the modules. About project SlidePlayer Terms of Service.
Seminar for you: Lighting protection using LFA-M
The roof circuit Interconnection to grounding electrodes Grounding electrodes. The rate of channel propagation on arrester modules is determined, and the. It assured reliable protection of medium voltage e. On the other hand, the potential of the adjacent phases also increases due to electromagnetic coupling between conductors but at much slower rate than that applied to the top phase insulator consequently, an outer phase arrester operates under much easier coordination conditions than a top phase arrester.
The induced over voltages can be counteracted by installing a single arrester on an overhead line support pole.
How does LFA-M protect the overhead lines?: Thus, the insulators of the healthy phases are stressed and flashed over by a voltage equal to the potential difference between the cross arm and the phase conductor. The over voltage set up due to the stroke may be large enough to flashover this path directly to the ground. Similarly, the semiconducting core of the lower piece of ptotection same lifhtning applies the low potential 0 to the surface of the upper piece, also at its center.
The induced over voltages can be counteracted by installing a single arrester on an overhead line support pole. Since the resistance of the flash over channel is low compared to other resistance affecting lightning over voltages surge impedance of the conductor and of the lightning channel, etc.
Are not stressed by operational voltage and do not require maintenance. 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.
Reduce the overall cost of the protection system.