Figure 140: Sotf Tripping; Figure 141: Sotf Tripping With Cnv - GE MiCOM P40 Agile Technical Manual

P543i/P545i
When busbar voltage transformers are used, the Pole Dead' signal is not produced. 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-energise a circuit once it had opened/tripped.
We recommend 110 seconds as a typical setting.
● SOTF Pulse: Typically this could be set to at 500ms. This time is enough to establish completely the voltage
memory of distance protection.
TOC Reset Delay: We recommend 500ms 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).
4.1.2 SOTF TRIPPING
SOTF Tripping
Zone 1
879
SOTF Active
960
Zone1 AN Element
961
Zone1 BN Element
962
Zone1 CN Element
963
Zone 1 AB Element
964
Zone1 BC Element
965
Zone1 CA Element

Figure 140: SOTF Tripping

4.1.3 SOTF TRIPPING WITH CNV
559
Fast OV PHA
864
IA < Start
560
Fast OV PHB
865
IB < Start
561
Fast OV PHC
866
IC< Start
879
SOTF Active
SOTF Tripping
Current No Volts

Figure 141: SOTF Tripping with CNV

4.2 TRIP ON RECLOSE (TOR)
Trip On Reclose (TOR) is special protection following auto-reclosure. The TOR status setting is used to enable or
disable TOR. When enabled, TOR is activated after the TOC Delay expires, ready for application when an auto-
reclose shot occurs.
When this feature is enabled, the protection operates in 'Trip on Reclose mode' for a period following circuit
breaker (CB) closure. Three-phase instantaneous tripping occurs for any fault detected by the selected zones or
CNV level detectors. Whether this feature is enabled or disabled, the normal time-delayed elements or aided
channel scheme continue to function and can trip the circuit.
The SOTF and TOR features stay in service for the duration of the TOC Reset Delay time, once the circuit is
energised. The delay timer starts on CB closure and is common for SOTF and TOR protection. Once this timer
expires after successful closure, all protection reverts to normal.
P54x1i-TM-EN-1
&
Note: This diagram shows Zone 1 only. The other zones follow the same
principles.
1
&
20 ms
& 1
&
0
&
Chapter 9 - Non-Aided Schemes
709
SOTF Trip Zone 1
556
CNV ACTIVE
558
SOTF Trip CNV
V02756
V02758
261