VAMP 259 - Page 55

Technical description
2 Protection functions
2.4 Distance protection Z<
VM259.EN007
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55
Figure 2.4.1-3 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 (21) :
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
Common parameters for all zones
LoadAngle
10 .. 40
°
40
Load angle 
LoadR
0.05 .. 250.00
ohm
1.00
Load resistance
X-, R- and Load resistance settings are secondary impedances.
Primary values of settings are displayed in VAMPSET
and display.
Voltage memory
A 0.5 second cyclic buffer storing the phase-to-earth voltages is
used as voltage memory. The stored phase angle information is
used as direction reference if all the phase voltages drop below
1% during a fault.