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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The over voltage set up due to the stroke may be large enough to flashover this path directly to the ground. Nice seminar on Lightning Protection. The direct lightning performance of the modular arresters was carried out using the equivalent circuits of fig 4.
It offers great number of technical and economical advantages. At this point, the calculation is stopped and the output is printed, usign the uing of the lightning current I 1 1 at which the insulator flashed over.
Are you interested in this topic. The direct stroke can be of two types. The cable pieces are arranged so as to form three flashover modules 1,2,3 as shown in figure1. The result is that charge on cloud R suddenly become free and it then proteection rapidly to earth, ignoring tall object.
Each cable piece has a semi conductive core of resistance R.
A new simple, effective and inexpensive method for lightning protection of medium voltage overhead distribution line is using long flashover arresters LFA. From the line, current path may be over at the ground. For a lightning pfa-m on a phase conductor, the lighting current propagates both ways from the stroke point overcoming the surge impedance Z s of the line.
The cloud will induce a charge of opposite sign on the tall object. Where k is the outage reduction factor of lightning outages caused by direct lightning strokes.
How does LFA-M protect the overhead lines? The efficiency of LFA lightning protection against direct lightning strokes can be expressed as the ratio of the number of lightning outages n 0 for unprotected line to n 0 for lines protected by LFA arresters. 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.
Semiconductive core of upper piece, whose resistance is R ,applies the high potential U to the surface of the lra-m piece at its middle. After the LFA A fully flashed over, the lightning current travels through the pole and its footing. The lightning protection failed. Protextion, 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.
Tests have been shown that, as the line conductor is stressed by lightning over voltage impulse, flash over channel develop at different rates. It lfa-n great number of technical and economical advantages. The direct stroke can be of two types 1. The induced over voltages can be counteracted by installing a single arrester on an overhead line support pole.
When cloud discharges to earth, -ve charge rushes along both directions in form of travelling wave.
Seminar for you: Lighting 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. Then it can withstand very high over voltages. Due to different propagation rates of flashover channels for lightning impulses of positive and negative polarity, the first module to flashover is module 1 protectino a flashover.
Both results put an.
LIGHTNING PROTECTION USING LFA-M
When the potential between the cloud and protecyion exceed the breakdown value of air, the lightning discharge occurs between the cloud and the line. Probability of power arc flow PAF depends on many parameters: The cable pieces are arranged so as to form three flashover modules 1,2,3 as shown in figure1. A new simple, effective and inexpensive method for lightning protection of medium voltage overhead distribution line is using long flashover arresters LFA.
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LIGHTENING PROTECTION USING LFA-M
Aim is to reduce the number of air terminals required by a traditional Franklin-type system. The induced over voltages can be counteracted by installing a single arrester on an overhead line support pole. Thus the total voltage is applied to protectoin flashover module at the same moment, and all the three flashover modules 1, 2 and 3 are assured conditions for simultaneous initiation of creeping discharges which,with respective modules flashed over, develop a single long flashover channel.
Vitthal Patnecha 13 January There are three clouds P,Q and R having positive, negative and positive charge respectively. Thus, t tr is larger than t cr.
LIGHTENING PROTECTION USING LFA-M – ppt video online download
LFA-Ls help avoid both conductor burnouts and overhead power lines outages caused by lightning induced over voltages. If the number of flashover modules increases by increasing the cable livhtning this LFA-M can be used for lightning protection of very high voltage lines.
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.
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 l 1. Lightbing of lightning II. Charge on the cloud Q is bound by cloud R. 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.
Long flashover arrestors are those devices which capture the high voltage sparks resulting out of lightening. Equation A4 of the Appendix is used to find the rate of propagation of discharge channels in modules 1 and 3 of arrester LFA A and the distance covered by these channels over time D t.
Newer Post Older Post Home. Lightning is a huge spark and that take place when clouds are charged to at a high potential with respect to earth object e. The above calculation does not take into account the effect of near-by poise: The important protecfion of this modular long flashover arrester LFA-M is that it can be applied for protction protection liightning overhead distribution line against both induced overvoltages and direct lightning strokes.