ABB RELION Series Technical Manual page 392

Section 4
Protection functions
386
The START output is activated once Start delay time has elapsed. OPERATE output is
activated once Operate delay time has elapsed and the above three conditions are
valid. Reset timer is started if any of the above three conditions is not valid. In case
fault is transient and self-extinguishes, START output stays activated until the elapse
of reset timer (setting Reset delay time). After OPERATE output activation, START
and OPERATE outputs are reset immediately, if any of the above three conditions is
not valid. The start duration value START_DUR, available in the Monitored data
view, indicates the percentage ratio of the start situation and the set operating time.
In case detection of temporary earth faults is not desired, the activation
of START output can be delayed with setting Start delay time. The
same setting can be also used to avoid restarting of the function during
long lasting post-fault oscillations, if time constant of post-fault
oscillations is very long (network losses and damping is low).
To keep the operate timer activated between current spikes during
intermittent or restriking earth fault, the Reset delay time should be set
to a value exceeding the maximum expected time interval between
fault spikes (obtained at full resonance condition). Recommended
value is at least 300 ms.
1MRS758755 A
REC615 and RER615
Technical Manual