TDn: Time multiplier for inverse time delay for step n.
IMinn: Minimum operate current for step n in % of IBase. Set IMinn below Pickupx for
every step to achieve ANSI reset characteristic according to standard. If IMinn is set above
Pickupx for any step then signal will reset at current equals to zero.
tnMin: Minimum operating 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 n can never be shorter than the setting.
IEC09000164-2
Operate time
Current
tx
tnMin
IMin n
IEC09000164 V2 EN
Figure 99: Minimum operate current and operate time for inverse time
characteristics
In order to fully comply with curves definition the setting parameter txMin shall be set to
the value which is equal to the operate time of the selected IEC inverse curve for measured
current of twenty times the set current pickup value. Note that the operate time value is
dependent on the selected setting value for time multiplier TDn.
7.6.3.2 Common settings for all steps
tx: Definite time delay for step x. Used if definite time characteristic is chosen.
AngleRCA: Relay characteristic angle given in degree. This angle is defined as shown in
figure
100. The angle is defined positive when the residual current lags the reference
voltage (Vpol = 3V
0
or V
2
)
Section 7 1MRK 506 334-UUS A
Current protection
206
Application manual
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