Explore Lightning Protection Using LFA-M with Free Download of Seminar Report and PPT in PDF and DOC Format. Also Explore the Seminar Topics Paper on Lightning Protection Using LFA-M with Abstract or Synopsis, Documentation on Advantages and Disadvantages, Base Paper Presentation Slides for IEEE Final Year Electronics and . Apr 24,  · The efficiency of LFA lightning protection against direct lightning strokes can be expressed as the ratio of the number Lighting protection using LFA-M. 1. contents: contents introduction what is a lightning stroke? types of lightning strokes. what is lfa-m? how lightning affects overhead transmission?
{/INSERT}

Author: Akijind Kazrazil
Country: Kosovo
Language: English (Spanish)
Genre: Photos
Published (Last): 11 November 2013
Pages: 69
PDF File Size: 15.82 Mb
ePub File Size: 15.46 Mb
ISBN: 556-1-81220-248-2
Downloads: 6717
Price: Free* [*Free Regsitration Required]
Uploader: Taukora

The probability of PAF sharply decreases with a decrease in E. This process is used to prevent automated posts. The suggested LFA accomplishes this principle. Therefore, in order to protect the line against the direct lightning stroke. It is seen from Lightning protection using lfa-m. A line with LFA arresters and INS insulators is shown to have a good lightning protection performance for direct lightning strokes.

The flashover length, L is greater for lines with wooden structures rather than steel or concrete structures, because a wooden crossarm increases the flashover path. How does LFA-M protect the overhead lines?

Thus, the number of outages caused by direct lightning strokes can be lowered with the use of Lightning protection using lfa-m arresters by an order of magnitude lightning protection using lfa-m more even for high values of grounding resistance.

Thus, the voltage on the cross arm increases at a much slower rate than it does on the lightning protection using lfa-m struck conductor before the flashover of the top phase LFA. Phase-to-phase faults on a pole can give rise to fault current in order of a few kiloampers.

Posted by Sagar at 4: 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.

Due to a special inner structure the LFA impulse flashover voltage is lower than that of the insulator and when subjected to lightning overvoltage the LFA will flashover before the insulator.

The direct stroke can be of two types 1. Pole-top arresters were used to protect distribution line from induced voltage flashovers. It is designated as LFA-M. From the line, current path may be over the insulators down to the pole to the ground.

TOP Related Posts  CD4089 DATASHEET PDF

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.

Use ” ” for compulsory search eg: It is seen from Fig.

lightning protection using lfa-m The conditions for the efficient protection of a medium voltage e. The average span length Ispan of a 10kV line is usually about 70m. From the short analysis presented above, it is clear that it is possible to improve the protection against lightning by increasing the length of lightning flashover path.

When the lightning protection using lfa-m between the cloud and line exceed the breakdown orotection of air, the usimg discharge occurs between the cloud and the line.

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. Some results of published experimental studies on the critical gradient are shown in fig3.

It is designated as LFA-M.

Seminar for you: Lighting protection using LFA-M

It is stressed suing fairly steep over protcetion impulses associated with direct lightning strokes on a conductor. Furthermore, the arresters and insulators are checked for flashover based on their voltage-time characteristics. Phase to phase lightning flashover is also highly probable to occur resulting to a power arc accompanied by heavy short circuit currents, lightning protection using lfa-m causes immediate line tripping.

Thus, the voltage on the cross arm increases at a much slower rate than it does on the lightning struck conductor before the flashover of the top phase LFA. The over voltage set up due to the stroke may be large enough to flashover this path directly to the ground.

Its special resistors assure application of the total arrester-stressing voltage simultaneously to all the modules. The main problem of using pole-top arresters is their high cost. The voltage rate of rise Ul is proportional to lightning protection using lfa-m of the lightning current.

Similarly, the semiconducting core of the lower piece of the same resistance applies the low potential lightning protection using lfa-m to the surface of the upper piece, also at its center. Automatic street light lightnibg gsm and AT89s52 microcontroller.

Then mail to us immediately to get the full report. It can be clearly seen that as the grounding resistance increases, the critical lightning current steepness I l l ligytning decreases.

The general pattern is as follows.

TOP Related Posts  100 ESCOVADAS ANTES DE DORMIR EBOOK

A single LFA lightning protection using lfa-m support or pole is found to be lightning protection using lfa-m to protect an over head line against induced over voltages. 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 induced over voltages can be counteracted by installing a single arrester on an overhead line support pole. Due to different propagation rates of flashover channels for lightning impulses of positive and negative polarity, the first module to flashover is module 1 with a flashover length of l1. Due to protectiln propagation rates of flashover libhtning for lightning impulses of positive and negative polarity, the first module to flashover is module 1 with a flashover length of l1.

For the protection of lines against direct lightning strokes, the arresters are connected between the poles and all of the lightning protection using lfa-m conductors in parallel with the lightnjng. When cloud discharges to earth, -ve charge rushes along both directions in form of travelling wave.

This is the main difference from conventional arresters which deal with the problem of extinguishing the power arc. At instants t4, lightning protection using lfa-m, and t6 the first, third, and second modules of arrester LFA resistance of the arrester. The above calculation does not take into account the effect of near-by poise: The over voltage set up protedtion to the stroke may be large enough to flashover this path directly to lightning protection using lfa-m ground.

At this point, the calculation is stopped and the output is printed, including the steepness of the lightning current I11 at which the 16 insulator flashed over.

To prevent transition of an impulse flash over to a PAF, the total flashover path L must be long.

The cable pieces are arranged so as to form three flashover modules 1,2,3 lightning protection using lfa-m shown in figure1. Next, lightning protection using lfa-m insulators and arresters voltage-time characteristics VTCs are entered in an analytical form. On the other hand, the potential of the adjacent phases also increases due lfs-m electromagnetic coupling between conductors but at much slower rate protsction that applied to the top phase insulator consequently, an outer phase arrester operates under much easier coordination conditions than a top phase arrester.