GE MiCOM P40 Agile - Calculation of Vk for Distance Zone 1 Close-Up Fault

6.13 CALCULATION OF VK FOR DISTANCE ZONE 1 CLOSE-UP FAULT
SIR = Z
s
/Z
zone1
=3.32/38.73, which is less than 2, so we need to calculate Vk.
Close-up fault current = 40kA primary, = 33.33A secondary
V
k
³ K
max
´ I
fmax
(R
CT
+ R
L
)
V
k
> 1.4 ´ 33.3 ´ (R
CT
+ R
L
), therefore:
V
k
> 46.67(R
CT
+ R
L
)
6.14 CALCULATION OF VK FOR DISTANCE TIME DELAYED ZONES
V
k
> I
f
(R
CT
+ R
L
)
V
k
> I
fthrough
´ (R
CT
+ R
L
), therefore:
V
k
> 2.14(R
CT
+ R
L
)
6.15
OVERCURRENT ELEMENTS
Phase Elements
V
K
³ 0.5I
CP
(R
CT
+ R
L
+ R
rp
)
Ground Elements
V
K
³ 0.5I
CN
(R
CT
+ 2R
L
+ R
rp
+ R
rn
)
6.16
OVERCURRENT ELEMENTS
V
K
³ 0.5I
CN
(R
CT
+ 2R
L
+ R
rn
)
Chapter 16 - Current Transformer Requirements P543i/P545i
426 P54x1i-TM-EN-1