Lightning strokes, which total 200 kA or 300 kV, cause hazards on the equipment or location, so lightning protection is vital for operation.
Why don't we commence with the initial note in regards to what is lightning and why lightning protection is so important. The basic phenomenon behind lightning is always that charges accumulated in the cloud as well as the earth are equal and opposite. This forms a non-uniform potential gradient surface up. If the gradient is larger compared to potential of the surface, the breakdown occurs along with a "streamer" flows from your cloud for the earth.
An immediate stroke happens when the lightning hits the ability systems directly the immense potential will result in destruction of the equipment or even the facility. As opposed, an indirect stroke occurs from the lightning discharges inside the proximity with the power line or from electrostatic discharge around the conductor due to charged clouds.
The principle power system elements requiring lightning protection are power feeds, home security systems, telephone lines, data and control systems and RF cables.
Types of Lightning Protection. The rolling sphere method is useful for identifying the actual keeping the lightning and surge protection devices close to the equipment under operation.
Protection in the power line against direct strokes is thru a ground wire or protector tube. The first kind produces electrostatic screening, which is afflicted with the capacitances from the cloud to line and the line to ground. Aforementioned forms an arc relating to the electrodes, causing gas deionisation.
Rooftop/Frame Protection. It really is interesting to notice how the building and rooftop frame or cladding is preferably metal than insulation type.
Setting up a finial towards the top of the energy tower must have a nominal amount distance of merely one.5 m over the highest antenna or lights. Such a rooftop or building frame is made of reinforced steel for protection purpose.
Wooden towers without downconductors might cause a fire hazard, since they route the incoming charges to ground. In principal, for non-metallic roofs, proper downconductors must be installed in the appropriate location and height.
Device Protection. Antenna lightning protection is supplied through spark gap, the gas discharge tube and quad-wavelength shorted stub. The 1st method uses ball points so that if your strike occurs, high potential forms bewteen barefoot and shoes and also the ground. The next method causes gas deionisation through arc formation relating to the electrodes. The very last method utilizes a coax transmission line through the transmission line to ensure that system bandwidth is narrow.
A lightning arrester can be a device offering lightning protection by regulating spark gaps. The unit classification may cover anything from rod gap, horn gap and valve type to metal oxide lightning arresters.
Earthing and Bonding Solutions. Now let's find how earthing and bonding solutions for lightning protection ought to be afforded. Design for earth rods, terminals or clamps ought to be in ways to route the incoming transients to earth to minimise step and touch potentials. The geometric measurements chosen should abide by the IEEE and NFPA standards. Any earthing system should have proper bonding, as ground potential rise can't be compensated. Again, the quantity of interconnects and spacing ought to be designed per the lightning standards.
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