GE P743 - Differential Current Display; Operation of Non Protection Functions; IRIG-B Signal (P741) Only; Programmable Scheme Logic

P74x/EN OP/
Na7
Operation
(OP) 5
-
42
MiCOM P741, P742
, P743
OP
4. OPERATION OF NON PROTECTION FUNCTIONS
4.1 Programmable scheme logic
4.1.1 Level settings
Name Range Step Size
Time delay t 0-14400000ms 1ms
4.1.2 Accuracy
Output conditioner timer
Setting ±2% or 50ms whichever is greater
Dwell conditioner timer
Setting ±2% or 50ms whichever is greater
Pulse conditioner timer
Setting ±2% or 50ms whichever is greater
4.2 IRIG-B signal (P741) only
If a satellite time clock signal conforming to IRIG-B is provided and the P741 relay has the
optional IRIG-B port fitted, the satellite clock equipment should be energised.
In the event of the auxiliary supply failing, with a battery fitted in the compartment behind the
bottom access cover, the time and date will be maintained. Therefore, when the auxiliary
supply is restored, the time and date will be correct and not need to be set again.
The P741 synchronises all peripheral units (P742/P743) every 10s and during the powering
on of the scheme.
4.3 Differential current display
When the differential currents are low, it is possible to force to 0 the value of these
differential currents displayed in the column MEASUREMENT 1 & MEASUREMENT 2 .
When the differential currents of a zone are all lower than the threshold (on the 3 phases),
the currents displayed are forced to 0.