ABB RELION REX640 Technical Manual page 933

1MRS759142 C
REX640
Technical Manual
The swing angles, δ and δ
0
crossing the blinders. It is the difference in these quantities that is important for
determining the slip frequency.
If the "Adaptive" option is selected, after detecting an OSB condition, the function
further examines the slip frequency f
outer blinder (δ ) to determine if the operate is asserted on the way in or on the way out.
0
OPERATE is activated on the way in, entering the mho circle from an inner blinder, if
the relationship in Equation 231
( )
π δ
−
f 0
≤
slip
VoltagedipTm
π
⋅
GUID-8DD67C79-D966-401F-A67C-47841B4FF9B4 V1 EN
f Slip frequency
slip
δ Swing angle at the outer blinder
0
VoltagedipTm Set V dip time
Otherwise, OPERATE is activated on the way out, when the impedance exits an outer
blinder and the swing repeats for the set Max number slips count in the respective
enabled zone that the swing has passed through.
If the Swing time has elapsed but the impedance exits the inner blinder and continues
through the opposite blinders without passing through the mho circle, the SWING
output is activated. The SWING output remains activated for a time determined by the
Reset time setting unless another swing occurs before the reset time expires causing
the output to remain active for another Reset time interval. If this swing is repeated for
the set Max Num slips Zn3 count and the Zone 3 enable setting is "Yes", the
SWING_OP output is activated. The SWING_OP output remains activated for a time
determined by the Operate dropout time setting.
If the "Adaptive" option is selected and an OSB condition is not detected, but the
impedance enters the mho circle after remaining between the inner and outer blinders
for greater than 1.5 cycles, the function assumes a severe swing and assert the
OPERATE output.
The drop out delay for OPERATE output can be set by Operate dropout time setting.
If the polarity of the voltage signal is opposite to the normal polarity, the correction
can be done by setting Voltage reversal to "Yes", which rotates the impedance vector
by 180 degrees.
The DISABLE input can be used to coordinate the correct operation during the start-
up situation. The function is blocked by activating the DISABLE signal. Once the
DISABLE signal is deactivated, the function remains blocked (outputs disabled) for
additional time duration as set through the setting Disable time.
, are estimated from the measured impedance when
I
, V dip time setting, and swing angle at the
slip
is true.
Section 4
Protection functions
(Equation 231)
927