GE P742

P74
x/EN ST/Na7
Settings
(ST) 4
-
22
MiCOM P74
1, P742, P743
ST
Menu Text Default Setting
Setting Range
Step Size
Min. Max.
CB FAIL
Control by
I< I< / 52a / both
Setting which determines the elements that will reset the circuit breaker fail time protection
function.
Both means that 52a and current criteria have to indicate open to reset the CB fail.
I< Current Set
0.05*I
n
0.05*I
n
4.00*I
n
0.01*I
n
Setting that determines the circuit breaker fail timer reset current for overcurrent based
protection circuit breaker fail initiation.
I> Status Disabled Enabled/Disabled
I> Current Set 1.2*In
0.05*I
n
4.00*I
n
0.01*I
n
IN> Current Set 0.2*In
0.05*I
n
4.00*I
n
0.01*I
n
Internal trip
Initiated by a Central Unit trip order
CB Fail Timer 1 0.05 s 0.00 s 10.00 s 0.01 s
Setting for the circuit breaker fail timer stage 1 for which the initiating condition must be
valid.
CB Fail Timer 2 0.20 s 0.00 s 10.00 s 0.01 s
Setting to enable or disable the second stage of the circuit breaker function.
External trip
Initiated by an external trip order or integrated overcurrent
CB Fail Timer 3 0.05 s 0.00 s 10.00 s 0.01 s
Setting to enable or disable the first stage of the circuit breaker function initiated
externally.
CB Fail Timer 4 0.20 s 0.00 s 10.00 s 0.01 s
Setting to enable or disable the second stage of the circuit breaker function inititated
externally.
1.2.8 CT Supervision (“Supervision” menu)
The CT Supervision (CTS) feature operates on detection of derived zero sequence current.
Menu Text Default Setting
Setting Range
Step Size
Min. Max.
SUPERVISION
Ι
O
Supervision
Sub-heading
Error Factor K
CE
0.40 0.01 1 0.01
Setting for the supervision characteristic for the slope (error coefficient)
Alarm Delay T
CE
5.0 s 0.0 s 10.0 s 0.1 s
Setting that determines the operating time-
delay of the element upon detection of a
current transformer supervision condition.
I0 sup. blocking 87BBP&87BBN 87BBP&87BBN / None
When IN is measured (application with a dedicated measurement CT to measure neutral
current), and when discrepancies between measured and derived values are identified,
the I
O
supervision can block the differential busbar protection (87BB — phase and neutral)
protection or does not block any protection.