ABB REB670 Series, Applications Manual

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IMinx
Operate time
Current
tx
txMin
IEC10000058
IEC10000058 V2 EN-US
Figure 87: Minimum operate current and operate time for inverse time characteristics
In order to fully comply with the definition of the curve, the setting parameter
txMin shall be
set to a value equal to the operating time of the selected inverse curve for twenty times the set
current pickup value. Note that the operate time is dependent on the selected time multiplier
setting kx.
ResetTypeCrvx: The reset of the delay timer can be made as shown in Table 27 .
Table 27: 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 24 for the time characteristic equation. For
more information, refer to Technical manual.
1MRK 505 370-UEN D Section 7
Current protection
Busbar protection REB670 147
Application manual