Common Settings For All Steps - ABB REQ650 Applications Manual

Section 6
Current protection
6.6.3.2
120
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 kn.

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 60. The angle is defined positive when the residual current lags the reference
voltage (Upol = 3U or U
0
RCA
I>Dir
IEC05000135 V4 EN
Figure 60: Relay characteristic angle given in degree
In a normal transmission network a normal value of RCA is about 65°. The setting
range is -180° to +180°.
polMethod: Defines if the directional polarization is from
• Voltage (3U or U
0 2
• Current (3I · ZNpol or 3I
0
• both currents and voltage, Dual (dual polarizing, (3U
· ZNpol)).
Normally voltage polarizing from the internally calculated residual sum or an external
open delta is used.
)
2
Upol = 3U
Operation
en 05000135 -4-nsi.vsd
)
·ZNpol where ZNpol is RNpol + jXNpol), or
2
1MRK 505 291-UEN A
or U
0 2
+ 3I · ZNpol) or (U
0 0
Application manual
+ I
2 2