GE P54C - Sensitive Earth Fault Protection Logic; Figure 102: EPATR B Characteristic Shown for TMS = 1.0; Figure 103: Sensitive Earth Fault Protection Logic Diagram

EPATR Curve
1
1
0
100
1000
0.1 1 10 100 1000
Current in Primary A (CT Ratio 100A/1A)
T
i
m
e
i
n
S
e
c
s
V00616
Figure 102: EPATR B characteristic shown for TMS = 1.0
5.3 SENSITIVE EARTH FAULT PROTECTION LOGIC
&
ISEF>1 Timer Blk
IN>1 Start
IN>1 Trip
&
V00738
IN
Inhibit ISEF>1
CTS Block
ISEF>1 Current
VTS Slow Block
ISEF> Blocking
VTS Blocks IN>1
VN
ISEF> VNpol Set
&
IDMT/ DT
Directional
check
ISEF>1 Direction
IN
Low Current
&
Residual voltage polarisation
ISEF> Blocking
AR Blks ISEF>3
* Stages 3 and 4 only
*
Note: For the purpose of clarity , this diagram shows the first
relevant stage number for each signal and setting name .
928
1724
833
409
777
671
Figure 103: Sensitive Earth Fault Protection logic diagram
Chapter 9 - Current Protection Functions P54A/B/C/E
208 P54xMED-TM-EN-1