GE MiCOM P40 Agile User Manual

6.4 CALCULATION OF TOTAL IMPEDANCE UP TO REMOTE BUSBAR
Z
T
= Z
S
+ Z
L
:
= 8.988+ j50.917 ohms =51.7 ohms angle 80°
6.5 CALCULATION OF THROUGH FAULT X/R RATIO
X/R
through
= 50.917 / 8.988 = 5.66
6.6
CALCULATION OF THROUGH FAULT CURRENT
I
f through
= 230kV / (1.732 ´ 51.7) = 2568.5 A primary = 2.14 A secondary
6.7
CALCULATION OF LINE IMPEDANCE TO ZONE 1 REACH POINT
Z
zone 1
= 0.8ZL = 7.12 + j 38.08 = 38.73 ohms angle 79.4°
6.8
CALCULATION OF TOTAL IMPEDANCE TO ZONE 1 REACH POINT
Z
T zone 1
= Z
S
+ Z zone 1 = 7.208 + j 41.397 = 42.019 ohms angle 80°
6.9
CALCULATION OF X/R TO ZONE 1 REACH POINT
X/R
zone 1
= 41.397 / 7.208 = 5.74
6.10
CALCULATION OF FAULT CURRENT TO ZONE 1 REACH POINT
I
f zone 1
= 230kV / (1.732 ´ 42.019) = 3160.34 A primary = 2.63 A secondary
6.11
CALCULATION OF VK FOR CURRENT DIFFERENTIAL PROTECTION
Transient Bias Disabled, with k2 set to 150%
I
f through
´ X/R
through
= 2.14 ´ 5.66 = 12.11
As this is less than 1000, we use the highest of K = 65 or K = 40 + (0.07(I
f
´ X/R))
Hence in this example we use K = 65. Therefore:
We know that V
k
³ KI
n
(R
CT
+ 2R
L
), therefore
V
k
³ 65(R
CT
+ 2R
L
)
Transient Bias Enabled, with k2 set to 150%
K = (1.42 ´ 2.14 + 53.7)(6.06E-03 ´ 5.66 + 0.515) = 31.2, therefore
V
k
³ 31.2(R
CT
+ 2R
L
)
6.12
CALCULATION OF VK FOR DISTANCE ZONE 1 REACH POINT
Using: V
k
³ K
RPA
´ I
fZ1
(1+ X/R)(R
CT
+ R
L
)
V
k
> 0.6 ´ 2.63 ´ (1 + 5.74)(R
CT
+ R
L
), therefore:
V
k
> 10.65(R
CT
+ R
L
)
P543i/P545i Chapter 16 - Current Transformer Requirements
P54x1i-TM-EN-1 425

GE MiCOM P40 Agile Specifications

General

Brand	GE
Model	MiCOM P40 Agile
Category	Control Unit
Language	English