Application Notes P54x/EN AP/La4
MiCOM P543, P544, P545 & P546
(AP) 6-31
AP
R
Z5
ZL
Z6
Z5'
Z6'
R5
R6R5'R6'
+jX
MOV’s operation
∆R
Figure 9 Example of timer reset due to MOV’s operation
Note: If ‘OST’ setting is chosen, the timer when triggered, will eventually
expire as the power oscillations progress, therefore MOV operation
will not have any impact on Out of Step operation.
2.3.18 Switch on to fault (SOTF) and trip on reclose (TOR) (Distance option only)
2.3.19
Switch onto fault mode (Distance option only)
To en
sure fast isolation of faults (for example a closed three phase earth/grounding switch)
upon energization, it is recommended this feature is enabled with appropriate zones and/or
‘Current No Volt’ (CNV) level detectors, depend on utility practices.
When busbar VTs are used, ‘Pole Dead’ signal will not be produced and a user has to
connect circuit breaker auxiliary contacts for correct operation. This is not necessary if the
SOTF is activated by an external pulse.
SOTF delay
- The time chosen should be longer than the slowest delayed-
auto-reclose dead time, but shorter than the time in which the
system operator might re-energize a circuit once it had
opened/tripped. 110 seconds is recommended as a typical
setting.
SOTF pulse
- Typically this could be set to at 500 ms. This time is enough to
establish completely the voltage memory of distance protection.
TOC reset delay
- 500 ms is recommended as a typical setting (chosen to be in
excess of the 16 cycles length of memory polarizing, allowing
full memory charging before normal protection resumes).
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