ABB REC670 Applications Manual page 184

Section 8
Current protection
178
tx: Definite time delay for step x. The definite time tx is added to the inverse time
when inverse time characteristic is selected. Note that the value set is the time
between activation of the start and the trip outputs.
kx: Time multiplier for the dependent (inverse) characteristic.
IMinx: Minimum operate current for step x in % of IBase. Set IMinx below Ix> for
every step to achieve ANSI reset characteristic according to standard. If IMinx is
set above Ix> for any step the ANSI reset works as if current is zero when current
drops below IMinx.
IxMult: Multiplier for scaling of the current setting value. If a binary input signal
(ENMULTx) is activated the current operation level is multiplied by this setting
constant.
txMin: Minimum operation time for 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.
Operate time
tx
txMin
IMinx
IEC10000058 V2 EN-US
Figure 77: Minimum operate current and operation time for inverse time
characteristics
ResetTypeCrvx: The reset of the delay timer can be made in different ways. By
choosing setting there are the following possibilities:
Curve name
Instantaneous
IEC Reset (constant time)
ANSI Reset (inverse time)
The different reset characteristics are described in the Technical Reference Manual
(TRM). There are some restrictions regarding the choice of reset delay.
1MRK 511 401-UEN A
Current
IEC10000058
Bay control REC670 2.2 IEC
Application manual