ABB REL670 2.2 IEC, Applications Manual

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jX
R
ZPE/2
ß
ArgLd
(Ref)
?
O
rc
F
φ
Load
|Zlo
ad|
|Zlo
ad|
/2
Ohm/phase
en06000406.vsd
IEC06000406 V1 EN-US
Figure 132: Definition of the setting condition to avoid load encroachment for
earth-fault loop
The maximum setting for phase-to-phase fault can be defined by trigonometric
analyze of the same figure
132 . The formula to avoid load encroachment for the
phase-to-phase measuring elements will thus be according to equation 183 .
Load
Z
ZPP 1.6
2 (1 cos( PP))
j
£ ×
× -
EQUATION1605 V1 EN-US
(Equation 183)
where:
j
PP = 180°–2·(ArgPP-
Q
Load)
All this is applicable for all measuring zones when no power swing detection
element or blinder is activated for the protection zones. Use an additional safety
margin of approximately 20% in cases when a power swing detection element is in
the protection scheme, refer to the description of the power swing detection
function.
8.4.3.9 Load impedance limitation, with load encroachment function
activated
SEMOD154469-129 v3
The parameters for load encroachment shaping of the characteristic are found in the
description of Faulty phase identification with load encroachment for mho
(FMPSPDIS), refer to section
"Load encroachment characteristics" .
1MRK 506 369-UEN B
Section 8
Impedance protection
Line distance protection REL670 2.2 IEC 259
Application manual