Lightning strokes, which add up to 200 kA or 300 kV, cause hazards towards the equipment or location, so lightning protection is important for operation.
Allow us to focus on the first note in regards to what is lightning and why lightning protection can be so important. Principle phenomenon behind lightning is the fact that charges accumulated from your cloud along with the earth are equal and opposite. This forms a non-uniform potential gradient surface in mid-air. If the gradient is bigger than the potential from the surface, the breakdown occurs and a "streamer" flows in the cloud on the earth.
A direct stroke takes place when the lightning hits the power systems directly that this immense potential can cause destruction of the equipment or perhaps the facility. In comparison, an indirect stroke occurs from the lightning discharges from the proximity of the power line or from electrostatic discharge around the conductor due to the charged clouds.
The main power system elements requiring lightning protection are power feeds, home security systems, telephone lines, data and control systems and RF cables.
Ways of Lightning Protection. The rolling sphere strategy is utilized for identifying the actual keeping the lightning and surge protection devices near the equipment under operation.
Protection of the power line against direct strokes is via a ground wire or protector tube. The former produces electrostatic screening, that's affected by the capacitances from the cloud to line and also the line to ground. The second forms an arc relating to the electrodes, causing gas deionisation.
Rooftop/Frame Protection. It is interesting to make note of the building and rooftop frame or cladding is preferably metal than insulation type.
Installing a finial near the top of the electricity tower needs to have the very least distance of merely one.5 m above the highest antenna or lights. This type of rooftop or building frame is made of reinforced steel for protection purpose.
Wooden towers without downconductors might cause a hearth hazard, while they route the incoming charges to ground. In principal, for non-metallic roofs, proper downconductors must be installed at the appropriate location and height.
Device Protection. Antenna lightning protection is given through spark gap, the gas discharge tube and quad-wavelength shorted stub. The first method uses ball points to ensure in case a strike occurs, high potential forms between them and the ground. The second method causes gas deionisation through arc formation between your electrodes. The final method uses a coax transmission line over the transmission line so that system bandwidth is narrow.
A lightning arrester is really a device offering lightning protection by regulating spark gaps. These devices classification may cover anything from rod gap, horn gap and valve type to metal oxide lightning arresters.
Earthing and Bonding Solutions. Now learn about how earthing and bonding solutions for lightning protection ought to be afforded. Design for earth rods, terminals or clamps must be in ways to route the incoming transients to earth to minimise step and touch potentials. The geometric measurements chosen should conform to the IEEE and NFPA standards. Any earthing system must have proper bonding, as ground potential rise can not be compensated. Again, the amount of interconnects and spacing should be designed per the lightning standards.
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