GE P24DM User Manual

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
V02756
SOTF Tripping
Zone 1
SOTF Active
&
Zone1 AN Element
Zone1 BN Element
Zone1 CN Element
Zone1 AB Element
Zone1 BC Element
Zone1 CA Element
1
SOTF Trip Zone 1
Note: This diagram shows Zone 1 only. The other zones follow the same
principles.
879
960
961
962
963
964
965
709
Figure 140: SOTF Tripping
4.1.3
SOTF TRIPPING WITH CNV
V02758
Fast OV PHA
CNV ACTIVE
&
1&
&
20 ms
0
IA< Start
Fast OV PHB
Fast OV PHC
IB< Start
IC< Start
SOTF Tripping
Current No Volts
SOTF Active
SOTF Trip CNV
&
559
864
560
865
561
866
879
556
558
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.
P543i/P545i Chapter 9 - Non-Aided Schemes
P54x1i-TM-EN-1 261

GE P24DM Specifications

General

Brand	GE
Model	P24DM
Category	Control Unit
Language	English