ABB REL650 series Technical Manual page 112

Section 6
Impedance protection
106
Based on these voltages the reach characteristic is implemented with Sine comparator
(TRUE, if {Im(S1) · Re(S2) - Im(S2) · Re(S1)}>0) for following comparisons:
< -
0 arg(I) arg(VKRForward) 180
GUID-797D640A-0107-4C8F-B8EF-A71E116535FB V1 EN
< -
0 arg(VKRReverse) arg(I) 180
GUID-7E158828-B0FF-45C2-ABC0-DF115196D6EE V1 EN
When both the conditions are true, then the reach characteristic comparator is set as true
for phase to phase loops (or when load compensation is disabled).
X
L
180°
IZKR
IRef
ANSI11000266 V1 EN
Figure 37: Reach characteristic part of quadrilateral characteristic
In figure 37only forward characteristic is shown. Similarly, reverse
characteristic is also possible with VKRreverse.
In phase to ground loops along with the above comparison, one more additional criterion
is also checked with IRef (= I+IN ·1.5) for ground load compensation.
< -
0 arg(I Re f ) arg(VKRForward) 180
GUID-6AF75940-3FE7-48FB-A28F-6463B5082E8D V1 EN
< -
0 arg(VKRReverse) arg(I Ref ) 180
GUID-001C2691-638A-4D62-A402-369CF8CE80C1 V1 EN
If all the four comparators are true then reach characteristic of phase to ground loop is set
as TRUE.
<
<
IRef
VKRForward
V
I
R
a=7°
<
<
1MRK 506 335-UUS A
(Equation 3)
(Equation 4)
Zx
ZxRev
ANSI11000266_1_en.vsd
(Equation 5)
(Equation 6)
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