GE MiCOM P40

Line Impedance = 5.81 W
6.11.2 RESIDUAL COMPENSATION FOR EARTH FAULT ELEMENTS
The residual compensation factor can be applied independently to certain zones if required. This is a useful feature
where line impedance characteristics change between sections or where hybrid circuits are used. In this example
this is not the case, so a common kZN factor can be applied to each zone. This is set as ratio kZN Res Comp, and
angle KZN Res Angle:
We know that
k
ZN
= (Z
0
- Z
1
)/3Z
1
Now, performing the calculations iwht the given values ...
|Z
0
- Z
1
| = 1.15
|3Z
1
| = 1.452
Ð (Z
0
-Z
1
) = 72.9°
Ð3Z
1
= 79.4°
Thus ...
kZ
N
= 0.79 Ð 6.5°
Therefore set:
kZN Res Comp = 0.79
KZN Res Angle = -6.5°
6.11.3
ZONE 1 PHASE AND GROUND REACH SETTINGS
For the protection at Green Valley:
The required Zone 1 reach is to be 80% of the line impedance between Green Valley and Blue River substations.
Using the Setting Mode Simple:
● Set Zone 1 Ph Status and Zone 1 Gnd Stat. to Enabled
● Set Zone 1 Ph Reach and Zone 1 Gnd Reach to 80%
From this the protection algorithm automatically calculates the required Ohmic reaches.
Alternatively, using the Setting Mode Advanced, the values can be calculated and entered manually as follows:
Required Zone 1 reach = 0.8 x 100 x 0.484
Ð 79.4° x 0.12 = 4.64 Ð 79.4° W secondary
So:
●
Set Z1 Ph. Reach and Z1 Gnd. Reach = 4.64 W
● Set Z1 Ph. Angle and Z1 Gnd. Angle = 80°
6.11.4
ZONE 2 PHASE AND GROUND REACH SETTINGS
For the protection at Green Valley:
In Advanced mode:
Required Zone 2 impedance = line impedance of Green Valley to Blue River + 50% line impedance
from Blue River to Rocky Bay
P446SV Chapter 7 - Distance Protection
P446SV-TM-EN-1 159