ABB RELION 620 Series Technical Manual page 514

Section 4
Protection functions
508
The swing angles, δ and δ
0
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
(δ ) to determine if the trip is asserted on the way in or on the way out. Tripping is done
0
on the way in, entering the mho circle from an inner blinder, if the relationship in
84 is true.
( − )
π δ
0
f
≤
slip
VoltagedipTm
⋅
π
GUID-4FEE5C5D-B60F-42E5-AFED-0EBE46145537 V1 EN
f Slip frequency
slip
δ Swing angle at the outer blinder
0
V dip time
VoltagedipTm Set
Otherwise, tripping is done 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_TR output is activated.
The SWING_TR output remains activated for a time determined by the Trip 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 TRIP output.
The drop out delay for TRIP output can be set by Trip 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
, are estimated from the measured impedance when crossing
I
, V dip time setting, and swing angle at the outer blinder
slip
1MAC504801-IB E
Equation
(Equation 84)
620 series ANSI
Technical Manual