Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546
(OP) 5-151
OP
4.2.2 VT selection (P543/P545)
The MiCOM P543/P545 has a three phase Main VT input and a single phase Check Sync
VT input. Depending on the primary system arrangement, the main three phase VT for the
relay may be located on either the busbar side or the line side of the circuit breaker, with the
check sync VT being located on the other side. Hence, the relay has to be programmed with
the location of the main VT. This is done using the Main VT Location setting in the CT & VT
RATIOS menu.
The Check Sync VT may be connected to either a phase to phase or phase to neutral
voltage, and for correct synchronism check operation, the relay has to be programmed with
the required connection. The C/S Input setting in the CT & VT RATIOS menu should be set
to A-N, B-N, C-N, A-B, B-C or C-A A-N/1.732, B-N/1.732 or C-N/1.732 as appropriate.
4.2.3 Basic functionality (P543/P545)
S
ystem check logic is collectively enabled or disabled as required, by setting System
Checks in the CONFIGURATION menu. The associated settings are available in SYSTEM
CHECKS, sub-menus VOLTAGE MONITORS, CHECK SYNC and SYSTEM SPLIT. If
System Checks is selected to Disabled, the associated SYSTEM CHECKS menu becomes
invisible, and a Sys checks Inactive DDB signal is set.
In most situations where synchronism check is required, the Check Sync 1 function alone will
provide the necessary functionality, and the Check Sync 2 and System Split signals can be
ignored.
4.2.4 System check logic outputs (P54
3/P545)
When enabled, the MiCOM P543/P545 system check logic sets signals as listed below,
according to the status of the monitored voltages.
Line Live – If the Line voltage magnitude is not less than VOLTAGE MONITORS -
Live Voltage setting
Line Dead – If the Line voltage magnitude is less than VOLTAGE MONITORS -
Dead Voltage setting
Bus Live – If the Bus voltage magnitude is not less than VOLTAGE MONITORS -
Live Voltage setting
Bus Dead – If the Bus voltage magnitude is less than VOLTAGE MONITORS -
Dead Voltage setting
Check Sync 1 OK – If Check Sync 1 Status is Enabled, the Line and Bus voltages are both
live, and the parameters meet the CHECK SYNC - Check Sync 1 ----
settings
Check Sync 2 OK – If Check Sync 2 Status is Enabled, the Line and Bus voltages are both
live, and the parameters meet the CHECK SYNC - Check Sync 2 ----
settings
System Split – If SS Status is Enabled, the Line and Bus voltages are both live, and
the measured phase angle between the voltage vectors is greater than
SYSTEM SPLIT - SS Phase Angle setting
All the above signals are available as DDB signals for mapping in Programmable Scheme
Logic (PSL). In addition, the Checksync 1 & 2 signals are “hard coded” into the auto-reclose
logic.
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