GE P743 - Sensitive Earth Fault Element

Settings
P74x/EN ST/N
a7
MiCOM P74
1, P742, P743
(ST) 4-
15
ST
1.2.1.2 Sensitive earth fault element
The sensitive earth fault element is included for high impedance earthed systems and has
bias current control to guarantee stability under external faults or when there are significant
errors in the measurement CTs. The element is usually disabled for effectively earthed
systems with low impedance or solid earthing.
Menu Text Default Setting
Setting Range
Step Size
Min. Max.
DIFF BUSBAR PROT
Diff Earth Fault (Diff busbar protection menu second part)
Diff Earth Fault Disabled Enabled/Disabled
To enable (activate) or disable (turn off) the differential earth fault protec
tion function. When
activated, the following functions are accessible.
IBiasPh>Cur.
2000 A 50 A 30.000 A 10 A
Setting that determines the Earth fault element blocking characteristic
CZ Parameters
Earth Slope k
N
CZ 10% 0% 90% 1%
Slope angle setting for the check zone biased differential Earth element.
I
DN
CZ>2 Current
1200 A 10 A 30.000 A 10 A
Setting that determines the minimum differential operating current for the check zone
biased differential Earth element
Zone Parameters
Earth Slope k
N
2 10% 0% 90% 1%
Slope angle setting for all discriminating zone biased differential Earth elements
I
DN
>2 Current
1000 A 10 A 30.000 A 10 A
Setting that determines the minimum differential operating current for all the discriminating
zone biased differential Earth elements
Common
I
DN
>1 Current
100 A 10 A 500 A 10 A
Setting for the Neutral circuitry fault monitoring characteristic for the minimum pickup
Earth slope k
N
1 10% 0% 50% 1%
Slope angle setting for the Neutral circuitry fault monitoring characteristic.
I
DN
>1 Alarm Timer
5.0s 0.0s 600.0s 0.1s
Setting for the Neutral circuitry fault monitoring minimum pickup timer