IEEE 1410-2004 pdf download IEEE Guide for Improving the Lightning Performance of Electric Power Overhead Distribution Lines
3. Definitions
3.1 back flashover (lightning): A flashover of insulation resulting from a lightning stroke to part of a network or electric installation that is normally at ground potential.
3.2 basic impulse insulation level (BIL) (rated impulse withstand voltage) (surge arresters): Areference impulse insulation strength expressed in terms of the crest value of withstand voltage of a standardfull-impulse voltage wave.
3.3 critical impulse flashover voltage (CFO) (insulators): The crest value of the impulse wave that, underspecified conditions, causes flashover through the surrounding medium on 50% of the applications.
3.4 direct strike: A lightning stroke direct to any part of a network or electric installation.
3.5 distribution line: Electric power lines that distribute power from a main source substation to consum-ers, usually at a voltage of 34.5 kV or less.
NOTEThis guide applies only for voltages 69 kV and below..
3.6 flashover (general): A disruptive discharge through air around, or over, the surface of solid or liquidinsulation, between parts of different potential or polarity, produced by the application of voltage whereinthe breakdown path becomes sufficiently ionized to maintain an electrical arc.
3.7 ground electrode: A conductor or group of conductors in intimate contact with the ground for the pur-pose of providing a connection with the ground.
3.8 ground flash density (GFD) (N,): The average number of lightning flashes per unit area per unit time ata particular location.
3.9 guy insulator: An insulating element, generally of elongated form with transverse holes or slots for thepurpose of insulating two sections of a guy or to provide insulation between structure and anchor, and also toprovide protection in case of broken wires.
3.10 guy wire: A stranded cable used for a semiflexible tension support between a pole or structure and theanchor rod, or between structures.
3.11 induced voltage (lightning strikes): The voltage induced on a network or electric installation by anearby strike.
3.12 lightning first return stroke: A lightning discharge to ground initiated when the tip of a downwardstepped leader meets an upward leader from the earth.
3.13 lightning flash: The complete lightning discharge, most often composed of one or more leaders from acloud followed by one or more return strokes.
3.14 lightning outage: A power outage following a lightning flashover that results in system fault current,thereby necessitating the operation of a switching device to clear the fault.
3.15 lightning subsequent stroke: A lightning discharge that may follow a path already established by afirst stroke.
3.16 line lightning performance: The performance of a line expressed as the annual number of lightningflashovers on a circuit km or tower-line km basis.
3.17 metal-oxide surge arrester (MOSA): A surge arrester utilizing valve elements fabricated from non-linear resistance metal-oxide materials.
3.18 nearby strike: A lightning stroke that does not directly strike any part of a network but induces a significant overvoltage in it.
3.19 overhead ground wire (0HGW): Grounded wire or wires placed above phase conductors for the pur.Dose of intercepting direct strokes in order to protect the phase conductors from the direct strokes. They maybe grounded directly or indirectly through short gaps. Syn: shield wire.
3.20 shielding angle: The angle between the vertical line through the overhead ground wire and a line con-necting the overhead ground wire with the shielded conductor.
IEEE 1410-2004 pdf download
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