ABB RELION REX640, Техническое руководство, Страница: 570 / 1960

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. If the 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.
If 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 also be 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.
Protection functions 1MRS759142 F
570 REX640
Technical Manual