ABB RELION REX640 Technical Manual page 549

1MRS759142 C
REX640
Technical Manual
supervision, and which is further defined with setting Operating quantity
(available options are "Adaptive", "Amplitude" and "Resistive").
The START output is activated once Start delay time has elapsed. OPERATE output is
not valid in the "Alarming EF" mode. Reset timer is started if any of the above three
conditions are not valid. If the fault is transient and self-extinguishes, START output
stays activated until the elapse of reset timer (setting Reset delay time).
If detection of temporary earth faults is not desired, the activation of
START output can be delayed with setting Start delay time.
To keep the operate timer activated between current spikes during
intermittent or restriking earth fault, the Reset delay time should be set
above the maximum expected time interval between fault spikes
(obtained at full resonance condition). The recommended value is at
least 300 ms.
Section 4
Protection functions
543