IEEE 1783-2009 pdf download IEEE Guide for Test Methods and Procedures to Evaluate the Electrical Performance of Insulators in Freezing Conditions
atmospheric icing: The expression atmospheric icing” comprises all processes where drifting or fallingwater droplets, rain, drizzle, or wet snow in the atmosphere freeze or stick to any object exposed to theweather.
cold fog (freezing fog): Visible aggregate of minute, supercooled water droplets suspended near the earth’ssurface whose droplets freeze upon contact with exposed objects and form a coating of hoarfrost and/orglaze. When composed of ice crystals, it is termed ice fog. According to international definitions, fogreduces visibility below 1 km. Fog differs from clouds only in that the base of fog is at the earth’s surfactwhile clouds are above its surface. Fog is distinguished from haze by its appreciable dampness and greycolor. Mist may be considered as intermediate between fog and haze. Near industrial and heavy trafficareas, fog is often mixed with smoke and vehicle exhaust, and this combination is known as smog
conductivity: A material property given by the conduction-current density, divided by the applied electric.
field intensity.In general, it is a complex tensor quantity.
NOTE-In liquids, conductivity is often measured in units of microsiemens per centimeter (uS/cm).
creepage distance: See: leakage distance.
critical flashover voltage: The amplitude voltage of a given wave shape that, under specified conditions.
causes flashover through the surrounding mediumm on 50% of the voltage applications.
critical impulse flashover voltage (CFO): The crest value of the impulse voltage wave that, underspecified conditions, causes disruptive discharge through the surrounding medium on 50% of theapplications.
dew-point temperature: The temperature at which the water vapor in the gas begins to condense
discharge: The passage of electricity through gaseous, liquid, or solid insulation that does not normalyconduct electricity. Discharge is associated with nonlinear processes of avalanche ionization anddevelopment of electrically conducting plasma that may or may not be luminous.
disruptive discharge (flashover): A discharge that completely bridges the insulation under test, reducingthe voltage between the electrodes to a finite value that is nearly constant for all currents and is negligiblewith respect to the supply voltage.
disruptive discharge probability (flashover probability): The probability that one application of aprospective voltage of a given shape and type may cause a disruptive discharge.
disruptive discharge voltage (flashover voltage): The voltage causing the disruptive discharge for testswith direct voltage, alternating voltage, and impulse voltage chopped at or after the peak; the voltage at theinstant when the disruptive discharge occurs for impulses chopped on the front.
dry arc distance (strike distance): The shortest distance through the surrounding medium betweenterminal electrodes, or the sum of the distances between intermediate electrodes, whichever is the shorter.with the insulator mounted for dry flashover test.
drizzle: Drizzle is light precipitation consisting of liquid water drops smaller than that of rain, andgenerally smaller than 0.5 mm (0.02 in) in diameter, Precipitation rates due to drizzle are on the order ofless than mm/h at the ground.