Lightning strokes, which add up to 200 kA or 300 kV, cause hazards to the equipment or location, so lightning protection is essential for operation.
Let's start with the initial note about what is lightning and why lightning protection is so important. Principle phenomenon behind lightning is that charges accumulated from your cloud along with the earth are equal and opposite. This forms a non-uniform potential gradient surface via a flight. In the event the gradient is bigger compared to the potential in the surface, the breakdown occurs plus a "streamer" flows from the cloud for the earth.
A principal stroke takes place when the lightning hits the electricity systems directly the immense potential will result in destruction in the equipment or even the facility. In contrast, an indirect stroke is carried out in the lightning discharges within the proximity with the power line or from electrostatic discharge for the conductor due to charged clouds.
The primary power system elements requiring lightning protection are power feeds, home security systems, telephone lines, data and control systems and RF cables.
Methods of Lightning Protection. The rolling sphere technique is utilized for identifying the exact placement of the lightning and surge protection devices at the equipment under operation.
Protection in the power line against direct strokes is through a ground wire or protector tube. The previous produces electrostatic screening, which can be impacted by the capacitances in the cloud to line along with the line to ground. The latter forms an arc between your electrodes, causing gas deionisation.
Rooftop/Frame Protection. It's interesting to make note of that 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 the very least distance of merely one.5 m higher than the highest antenna or lights. This type of rooftop or building frame is constructed of reinforced steel for cover purpose.
Wooden towers without downconductors might cause a fireplace hazard, since they route the incoming charges to ground. In principal, for non-metallic roofs, proper downconductors ought to 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 initial method uses ball points in order that if your strike occurs, high potential forms bewteen barefoot and shoes along with the ground. The next method causes gas deionisation through arc formation relating to the electrodes. The last method runs on the coax transmission line throughout the transmission line to ensure that system bandwidth is narrow.
A lightning arrester is often 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 talk of how earthing and bonding solutions for lightning protection ought to be afforded. The design of earth rods, terminals or clamps must be in such a way to route the incoming transients to earth to minimise step and touch potentials. The geometric measurements chosen should comply with the IEEE and NFPA standards. Any earthing system needs to have proper bonding, as ground potential rise can't be compensated. Again, the volume of interconnects and spacing needs to be designed per the lightning standards.
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