Table 34: Reset possibilities
Curve name Curve index no.
Instantaneous 1
IEC Reset (constant time) 2
ANSI Reset (inverse time) 3
The delay characteristics are described in Technical manual. There are some restrictions
regarding the choice of the reset delay.
For the definite time delay characteristics, the possible delay time setting instantaneous
(1) and IEC (2 = set constant time reset).
For ANSI inverse time characteristics, all three types of reset time characteristics are
available: instantaneous (1), IEC (2 = set constant time reset) and ANSI (3 = current
dependent reset time).
For IEC inverse time characteristics, the possible delay time settings are instantaneous (1)
and IEC (2 = set constant time reset).
For the customer tailor-made inverse time delay characteristics (type 17), all three types
of reset time characteristics are available: instantaneous (1), IEC (2 = set constant time
reset) and ANSI (3 = current dependent reset time). If the current-dependent type is used,
settings pr, tr and cr must be given.
tResetx: Constant reset time delay in seconds for step x.
tPCrvx, tACrvx, tBCrvx, tCCrvx: These parameters are used by the customer to create the
inverse time characteristic curve. See equation
449 for the time characteristic equation.
For more information, refer to Technical manual.
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ANSI-EQUATION1261 V1 EN (Equation 449)
tPRCrvx, tTRCrvx, tCRCrvx: These parameters are used by the customer to create the
inverse reset time characteristic curve. For more information, refer to Technical manual.
HarmRestrainx: Enables the block of step x from the harmonic restrain function (2nd
harmonic). This function should be used when there is a risk of an unwanted trip caused
by power transformer inrush currents. It can be set to Disabled/Enabled.
Section 9 1MRK 506 369-UUS -
Current protection
498 Line distance protection REL670 2.2 ANSI
Application manual
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