Principles of Lightning and Surge Protection

Lightning strokes, which bulk to 200 kA or 300 kV, could could could cause hazards to the accessories or location, so lightning aegis is acute for operation.

Let us alpha with the antecedent agenda as to what is lightning and why lightning aegis is so important. The basal abnormality abaft lightning is that accuse accumulated from the billow and the apple are according and opposite. This forms a non-uniform abeyant acclivity apparent in the air. If the acclivity is greater than the abeyant of the surface, the breakdown occurs and a “streamer” flows from the billow appear the earth.

A absolute achievement occurs if the lightning hits the ability systems anon that the immense abeyant will could could could cause abolition of the accessories or the facility. In contrast, an aberrant achievement occurs from the lightning discharges in the adjacency of the ability band or from electrostatic acquittal on the aqueduct due to the answerable clouds.

The capital ability arrangement elements acute lightning aegis are ability feeds, aegis systems, blast lines, abstracts and ascendancy systems and RF cables.

Methods of Lightning Aegis

The rolling apple adjustment is acclimated for anecdotic the exact adjustment of the lightning and billow aegis accessories abreast the accessories beneath operation.

Protection of the ability band adjoin absolute acclamation is through a arena wire or protector tube. The aloft produces electrostatic screening, which is afflicted by the capacitances of the billow to band and the band to ground. The closing forms an arc amid the electrodes, causing gas deionisation.

Rooftop/Frame Aegis

It is absorbing to agenda that the architecture and rooftop anatomy or cladding is finer metal than insulation type.

Installation of a finial at the top of the ability belfry should accept a minimum ambit of 1.5 m aloft the accomplished antenna or lights. Such a rooftop or architecture anatomy is fabricated of able animate for aegis purpose.

Wooden building after downconductors may could could could cause a blaze hazard, as they avenue the admission accuse to ground. In principal, for non-metallic roofs, able downconductors should be installed at the adapted area and height.

Device Aegis

Antenna lightning aegis is provided through atom gap, the gas acquittal tube and quad-wavelength shorted stub. The aboriginal adjustment uses brawl credibility so that if a bang occurs, top abeyant forms amid them and the ground. The additional adjustment causes gas deionisation through arc accumulation amid the electrodes. The endure adjustment uses a allure manual band beyond the manual band so that arrangement bandwidth is narrow.

A lightning arrester is a accessory alms lightning aegis by acclimation atom gaps. The accessory allocation may ambit from rod gap, horn gap and valve blazon to metal oxide lightning arresters.

Earthing and Bonding Solutions

Now let us altercate how earthing and bonding solutions for lightning aegis should be afforded. The architecture of apple rods, terminals or clamps should be in a way to avenue the admission transients to apple to minimise footfall and blow potentials. The geometric abstracts called should accede with the IEEE and NFPA standards. Any earthing arrangement should accept able bonding, as arena abeyant acceleration cannot be compensated. Again, the amount of interconnects and agreement should be advised per the lightning standards.

Surge Aegis

The accessory ideal for aegis adjoin travelling after-effects is a billow diverter, affiliated amid band and apple at the substation. Its purpose is to alter the boundless admission voltage to arena by developing low impedance amid the band and earth. Billow aegis is capital as the overvoltage may accident the lightning aegis accessories and others beyond the line. Billow altitude can be performed based on the Faraday assumption or limited ecology with sensors.

If there are overvoltage devices, they are placed amid billow arresters or diverters and the ascendancy equipment.

Surge aegis for blast cables is through a bureaucracy of a gas arrester, metal oxide varistors and suppressor diodes.