ABB RELION REX640 Technical Manual page 951

1MRS759142 C
REX640
Technical Manual
GUID-78F8B964-B80B-495B-9064-DFB3123BC783 V1 EN
Figure 511: Origin-centric circular operating characteristics
More than one impedance value is available when Impedance Meas
mode is set to "3Phase-to-phase", and the function considers the
lowest impedance value for starting and operating.
Timer
Once activated, Timer activates START output. The time characteristic is according
to DT. When the duration of the underimpedance condition exceeds the set definite
Operate delay time, the OPERATE output is activated. If the impedance locus moves
out of circular operating characteristics before the module operates, the reset timer is
activated. If the reset timer reaches the value set by Reset delay time, the operating
timer resets and the START output is deactivated.
Timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operating time (DT). The value is
available in the Monitored data view.
Blocking logic
There are three operation modes in the blocking functionality. The operation modes
are controlled by the BLOCK input and the global setting Configuration/System/
Section 4
Protection functions
945