ABB RELION 620 Series Technical Manual page 512

Section 4
Protection functions
506
Zone 1
-R
Zone 3
GUID-5C2AD9EC-F994-4DB0-B061-6B1B6A10D891 V1 EN
Figure 242: Defined zones
Out of step condition is a symmetrical event, so out of step detection is enabled only if the
negative-sequence current is below the Max Ng Seq current setting.
The impedance is continuously monitored for detecting an out of step condition. When the
impedance enters inside from the outer blinder, the out of step detection timer is triggered.
If impedance remains between outer and inner blinder for the duration of the Swing time
setting, output SWING is activated. If the impedance enters the mho circle in zone 1, out
of step blocking (OSB) for zone 1 is detected and output OSB is activated, or if the
impedance enters the mho circle in zone 2, OSB for zone 2 is detected and output OSB_Z2
is activated if setting Zone 2 enable is set to "Yes". The OSB or OSB_Z2 output
deactivates when impedance exits and remains outside the mho circle and the inner
blinder for a duration of five cycles.
Activation of the TRIP output depends on the Oos trip mode selected. Trip mode options
available are "Way in", "Way out", and "Adaptive". If the "Way in" option is selected, the
function triggers the delay timer after detecting an OSB condition. When the set Trip delay
time has elapsed, the TRIP output is activated.
X
Zone 2
-X
1MAC504801-IB E
R
620 series ANSI
Technical Manual