ABB RET670 - Page 413

Table 88: 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 the technical reference manual. There are
some restrictions regarding the choice of reset delay.
For the definite time delay characteristics the possible delay time settings are
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.
HarmRestrainx: Enable block of step x from the harmonic restrain function (2nd
harmonic). This function should be used when there is a risk if power transformer
inrush currents might cause unwanted trip. Can be set Disabled/Enabled.
tPCrvx, tACrvx, tBCrvx, tCCrvx: Parameters for customer creation of inverse time
characteristic curve (Curve type = 17). See equation
340 for the time characteristic
equation.
[ ]
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p
A
t s B MultPUx
i
C
in
= + ×
-
æ ö
ç ÷
ç ÷
ç ÷
æ ö
ç ÷
ç ÷
è ø
è ø
ANSI-EQUATION1261 V1 EN (Equation 340)
For more information, refer to the technical reference manual.
tPRCrvx, tTRCrvx, tCRCrvx: Parameters for customer creation of inverse reset time
characteristic curve (Reset Curve type = 3). Further description can be found in the
technical reference manual.
1MRK504116-UUS C Section 3
IED application
407
Application manual