Alstom MiCOM P546 - 1.21 Switch on to fault (SOTF) and trip on reclose (TOR) (Distance option only)

P54x/EN OP/La4 Operation
(OP) 5-50 MiCOM P543, P544, P545 & P546
OP
Figure 28 Out of step algorithm (Distance option only)
1.21 Switch on to fault (SOTF) and trip on reclose (TOR) (Distance option only)
The setting
s for SOTF and TOR are included in the menu column TRIP ON CLOSE (TOC)
within the MiCOM P54x relay. The settings are designed to deal with two different
scenarios.
 SOTF is designed to provide instantaneous operation of selected elements for a fault
present on manual closure of the circuit breaker;
 TOR is designed to provide instantaneous operation of selected elements for a
persistent fault present on auto-reclosing of the circuit breaker.
The SOTF and TOR functions are communally termed Trip on Close logic. The operation
of these features is split into two Figures for clarity: Figure 29 shows Trip On Close function
in rel
ation with the Distance zones while Figure 30 presents Trip On Close driven by ‘Current
No Volt’ level
detectors. Both methods operate in parallel if mapped to the SOTF and TOR
Tripping matrix in the setting file.
The ’Current No Volt’ (CNV) level detectors are user settable in the ‘GROUP X CB FAIL & P.
Dead’ column. The same setting is used for pole dead logic detection – see Settings chapter
for more details. The 20 ms time delay in the Figure 30 is to avoid a possible race between
very fast overvoltage and u
ndercurrent level detectors.