ABB Relion REQ650, Applications Manual

Page: 126 / 340

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 .
6.6.3.2 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 60 . The angle is defined positive when the residual current lags the reference
voltage (Upol = 3U
0
or U
2
)
Upol = 3U
0
or U
2
I>Dir
RCA
Operation
en 05000135-4-nsi.vsd
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
0
or U
2
)
• Current (3I
0
· ZNpol or 3I
2
·ZNpol where ZNpol is RNpol + jXNpol), or
• both currents and voltage, Dual (dual polarizing, (3U
0
+ 3I
0
· ZNpol) or (U
2
+ I
2
· ZNpol)).
Normally voltage polarizing from the internally calculated residual sum or an external
open delta is used.
Section 6
1MRK 505 291-UEN A
Current protection
120
Application manual