VAMP 259 - Page 58

2.4 Distance protection Z<
2 Protection functions
Technical description
58
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VM259.EN007
Zones and characteristics
There are 5 zones (Z1e, Z2e, Z3e, Z4e and Z5e) for earth-fault
protection. These are implemented as protection stages Z1e<,
Z2e<, Z3e<, Z4e< and Z5e<. Z1e extension can be implemented
by applying second setting group to cover the extension zone in
auto-reclosing.
The distance protection‘s zones implement a polygonal
characteristics as shown in Figure 2.4.2-3.
Figure 2.4.2-3 The distance protection polygonal characteristics. In this
example zone 3 is in reverse direction and zone 5 is non-directional.
Parameters of the distance protection stage (21N) :
Parameter
Value
Unit
Default
Description
X
0.05 .. 250.00
ohm
0.80
X-setting
R
0.05 .. 250.00
ohm
0.80
R-setting
MODE
Reverse/Forw
ard/
Undirectional
Forward
Direction mode
t<
0.04 .. 300.00
s
Operation delay
LOAD
BLOCK
No/Yes
Yes
Load block in use
Io min
input
I
0
; IoCalc
-
I
0
I
0
input in use for
minimum I
0
current
Io min
0.005 .. 8.000
(20.000 for
IoCalc)
pu
0.050
Minimum Io current for
trip
Common parameters for all zones
LoadAngle
10 .. 40
°
40
Load angle 
LoadR
0.05 .. 250.00
ohm
1.00
Load resistance
Common parameters for all earth fault zones
k
0
0.00 .. 10.00
0.00
Earth factor
φ (k
0
)
-60 .. 60
°
10
Earth factor angle