17 Dec Explore Lightning Protection Using LFA-M with Free Download of Seminar Report and PPT in PDF and DOC Format. Also Explore the Seminar. Presentation on theme: “LIGHTENING PROTECTION USING LFA-M”— System ”-A system of lightning protection conductors lightning rods -installed on the. 13 Jan The important feature of this modular long flashover arrester (LFA-M) is that it can be applied for lightning protection of overhead distribution.

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A new simple, effective and inexpensive method for lightning protection of medium voltage overhead distribution line is using long flashover arresters LFA. Therefore, this new lightning protection system is thought to feature simple design, low cost, and high reliability. This voltage, however, is not as high as that for the lightning struck-conductor. Automatically changes to Flash or non-Flash embed. How does LFA-M protect the overhead lines?: Protection against Lightning Overvoltages Overvoltages due to lightning strokes can be avoided or minimized in practice by d shielding the overhead lines.

lightnjng The probability of PAF sharply decreases with a decrease in E. We think you have liked this presentation. For example world, us etc III.

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 above calculation does not take into account the effect of near-by poise: Similarly, the semiconducting core of the lower piece of the same resistance applies the low potential 0 to the surface of the upper piece, also at its center. Where n 0 is the number of lightning outages on an LFA protected line caused by direct lightning strokes on the phase conductors and P I lcr is probability of a lightning current with steepness greater or equal to I lcr The efficiency of LFA lightning protection against direct lightning strokes can be expressed as uaing ratio of the number of lightning outages n 0 for unprotected ,ightning to n 0 for lines protected by LFA arresters.

It was assumed to be equal to zero. Are you interested in this topic.

Then it can withstand very high over voltages. Opposite charges attract, like repel Charged objects can cause electrons to rearrange their positions on a neutral object. The rate of channel propagation on arrester modules is determined, and the. With one or both outer phase arresters activated, a two or three phase lightning flashover is initiated. Are not stressed by operational voltage and do not require maintenance.


An LFA-M arrester consists of two cables like pieces. In stroke B the lightning discharge occurs on the overhead line as the result of stroke A between the clouds. As seen in fig 3. From the line, current path may be over the insulators down lfa-n the pole to the ground. It is designated as LFA-M.


Induced over voltages can be counteracted by installing a single arrestor on an overhead line support. Thus, the voltage on the cross arm increases at a much slower rate than it does on the lightning struck conductor before the flashover lfw-m the proteection phase LFA.

The result is that charge on cloud R suddenly become free and it then discharges rapidly to earth, ignoring tall object. The calculation is carried out for a linear increase of the lightning current, that is.

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.

Aim is to reduce the number of air terminals required by a traditional Franklin-type system. The presentation is successfully added In Your Ligutning. This negative charge however will be only on that portion on the line right under liggtning cloud and the portion of the line away from it will be positively charged. Provides a low-impedance path for the lightning current to lighnting the heating effect. Due to electromagnetic coupling between phases, the potential of the healthy outer phases also increases and it can be assessed from lfa-k conductor coupling factor.

WordPress Embed Customize Embed. The flashover length, L is greater for lines with wooden structures rather than steel or concrete structures, because wooden Cross-arm increases the flashover path. The equivalent EMF e is calculated as follows. It is stressed by fairly steep over voltage impulses associated with direct lightning strokes on a conductor. A new long flashover arrester model has been developed. Auth with social network: The LFA’s length may be several times greater than that of an insulator string, etc.

Seminar for you: Lighting protection using LFA-M

A flowchart of the calculations is shown in fig6. It is designated as LFA-M. If a positively charged cloud is above the line and induces a negative charge on the line by electrostatic induction.

Charge on the cloud Q is bound by cloud R. The cloud will induce a charge of opposite sign on the tall object.