Apuntes descargadores
6
ANSI /IEEE C62.2-1987 2.6 Insulation Coordination. Insulation coordination is defined in ANSI C92.1-1982 [131 as “the process of correlating the insulation strengths of electrical equipment with expected overvoltages and with the characteristics of surge protective devices.’’ Degree of coordination is measured by the protective ratio (PR). The fundamental definition of PR is: insulation withstand level voltage at protected equipment “Voltage at protected equipment” includes separation effect, if significant. If not, it is equal to arrester protective level, plus the line and ground lead voltages. There are three protective ratios in common use, which compare protective levels with corresponding insulation with stands : Chopped-Wave Withstand (CWW) Front-of-Wave Sparkover (FOW) Basic Impulse Insulation Withstand (BIL) Lightning Protective Level (LPL) Switching Impulse Insulation Withstand (BSL) Switching Surge Protective Level (SSP) PR(1): CWW/FOW ≥ 1,2 PR(2): BlL/LPL ≥ 1,2 PR(3): BSL/SSP ≥ 1,15
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apuntes para la coordinación de protección en transformadores
Transcript of Apuntes descargadores
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ANSI /IEEE C62.2-1987
2.6 Insulation Coordination. Insulation coordination is defined in ANSI C92.1-1982 [131 as
the process of correlating the insulation strengths of electrical equipment with expected
overvoltages and with the characteristics of surge protective devices.
Degree of coordination is measured by the protective ratio (PR). The fundamental
definition of PR is:
insulation withstand level
voltage at protected equipment
Voltage at protected equipment includes separation effect, if significant. If not, it is equal
to arrester protective level, plus the line and ground lead voltages.
There are three protective ratios in common use, which compare protective levels with
corresponding insulation with stands :
Chopped-Wave Withstand (CWW)
Front-of-Wave Sparkover (FOW)
Basic Impulse Insulation Withstand (BIL)
Lightning Protective Level (LPL)
Switching Impulse Insulation Withstand (BSL)
Switching Surge Protective Level (SSP)
PR(1): CWW/FOW 1,2 PR(2): BlL/LPL 1,2
PR(3): BSL/SSP 1,15
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Tabla A1
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IEEE Std C62.22-1997 IEEE GUIDE FOR THE APPLICATION OF METAL-OXIDE
SURGE 14 Copyright 1998 IEEE. All rights reserved.
4.6 Insulation coordination
Insulation coordination is defined in IEEE Std 1313.1-1996 and in this guide as the selection of insulation strength consistent with expected overvoltages to obtain an
acceptable risk of failure.
Degree of coordination is measured by the protective ratio (PR). The fundamental
definition of PR is
Insulation Withstand Level
PR = ----------------------------------------------------------------------------
Voltage at Protected Equipment
Voltage at protected equipment includes separation effect, if significant. If not, it is equal to arrester protective level.
Three protective ratios are in common use, comparing protective levels with corresponding
insulation withstands.
(Acceptable ratio is 1.15)
(Acceptable ratio is 1.15)
(Acceptable ratio is 1.2)
The protective margin (PM) in percent is defined as: PM = (PR - 1)100. PR and PM
applications are covered in Clauses 5 and 6.
A graphical approach to insulation coordination is also discussed in 5.7.
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IEEE Std C62.22-1997
