ABB Relion REQ650, Applications Manual

Page: 113 / 340

Characteristn : Selection of time characteristic for step n . Definite time delay and
different types of inverse time characteristics are available according to Table 16 .
Step 2 and 3 are always definite time delayed.
Table 16: Inverse time characteristics
Curve name
ANSI Extremely Inverse
ANSI Very Inverse
ANSI Normal Inverse
ANSI Moderately Inverse
ANSI/IEEE Definite time
ANSI Long Time Extremely Inverse
ANSI Long Time Very Inverse
ANSI Long Time Inverse
IEC Normal Inverse
IEC Very Inverse
IEC Inverse
IEC Extremely Inverse
IEC Short Time Inverse
IEC Long Time Inverse
IEC Definite Time
ASEA RI
RXIDG (logarithmic)
The different characteristics are described in the Technical manual.
Ix> : Operation phase current level for step x given in % of IBase .
tx : Definite time delay for step x . Used if definite time characteristic is chosen.
kn : Time multiplier for inverse time delay for step n .
: Time multiplier for inverse time delay for step n .
IMinn : Minimum operate current for step n in % of IBase . Set IMinn below Ix> for
every step to achieve ANSI reset characteristic according to standard. If IMinn is set
above Ix> for any step the ANSI reset works as if current is zero when current drops
below IMinn .
tnMin : Minimum operate time for all inverse time characteristics. At high currents the
inverse time characteristic might give a very short operation time. By setting this
parameter the operation time of the step can never be shorter than the setting.
1MRK 505 291-UEN A
Section 6
Current protection
107
Application manual