IEEE C62.82.1-2010 pdf download

IEEE C62.82.1-2010 pdf download.IEEE Standard for Insulation Coordination-Definitions, Principles, and Rules.
3. Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary: Glossary of Terms & Definitions [B!] should be consulted for terms not defined in this clause.7
3.1 atmospheric correction factor: A factor applied to account for the difference between the atmospheric conditions in service and the standard atmospheric conditions.
NOTE—In terms of this standard, it applies to insulation exposed to the atmosphere only.
3.2 basic lightning impulse insulation level (BIL): The electrical strength of insulation expressed in terms of the crest value of a standard lightning impulse under standard atmospheric conditions. BIL may be expressed as either statistical or conventional.
3.3 basic switching impulse insulation level (BSL): The electrical strength of insulation expressed in terms of the crest value of a standard switching impulse. BSL may be expressed as either statistical or conventional.
3.4 conventional BIL (basic lightning impulse insulation level): The crest value of a standard lightning impulse for which the insulation shall not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specified conditions, applicable specifically to non-self-restoring insulations.
3.5 conventional BSL (basic switching impulse insulation level): The crest value of a standard switching impulse for which the insulation does not exhibit disruptive discharge when subjected to a specific number of impulses under specified conditions, applicable to non-self-restoring insulations.
3.6 conventional withstand voltage: The voltage that an insulation system is capable of withstanding without failure or disruptive discharge under specified test conditions.
3.7 crest value (peak value): The maximum absolute value of a function when such a maximum exists.
3.8 critical flashover (CFO) voltage: The amplitude of voltage of a given waveshape that, under specified conditions, causes flashover through the surrounding medium on 50% of the voltage applications.
3.9 effectively grounded system: A system grounded through a sufficiently low impedance such that for all system conditions the ratio of zero-sequence reactance to positive-sequence reactance (X0/X1) is positive and less than 3, and the ratio of zero-sequence resistance to positive-sequence reactance (R0/X1) is positive and less than 1.
3.10 external insulation: The air insulation and the exposed surfaces of solid insulation of equipment. which are both subject to dielectric stresses and to the effects of atmospheric and other external conditions such as contamination, humidity, and vermin.
3.11 front-of-wave lightning impulse voltage shape: A voltage impulse, with a specified rate-of-rise, that is terminated intentionally by sparkover of a gap that occurs on the rising front of the voltage wave with a specified time to sparkover, and a specified minimum crest voltage.
3.12 ground-fault factor: The ratio of the highest phase-to-ground power frequency voltage on an unfaulted phase during a line-to-ground fault to the phase-to-ground power-frequency voltage without the fault.
NOTE I—The ground-fault factor generally will be less than 1 .3, if the zero-sequence reactance is less than three times the positive-sequence reactance, and the zero-sequence resistance does not exceed the positive-sequence reactance.
NOTE 2—IEEE Std (‘62.1-1989 defines a “coefficient of grounding.” This coefficient can be obtained by dividing the ground-fault factor by J3.
The IEEE Standards Dictionary: Glossary of Terms & Definitions is available at http://shop.ieee.org/.
3.13 impedance grounded neutral system: A system whose neutral point(s) are grounded through an impedance (to limit ground-fault currents).
3.14 insulation configuration: The complete geometric configuration of the insulation, including all elements (insulating and conducting) that influence its dielectric behavior. Examples of insulation con figurations are phase-to-ground, phase-to-phase, and longitudinal.
3.15 insulation coordination: The selection of the insulation strength of equipment in relation to the voltages, which can appear on the system for which equipment is intended and taking into account the service environment and the characteristics of the available protective devices.
NOTE—An acceptable risk of failure is considered when selecting the insulation strength of equipment.
3.16 internal insulation: Internal insulation comprises the internal solid, liquid, or gaseous elements of the insulation of equipment, which arc protected from the effects of atmospheric and other external conditions such as contamination, humidity, and vermin.