ABB RELION 670 Series Applications Manual page 375

1MRK 504 152-UEN B
=
ZC
EQUATION1975 V2 EN-US
Set ZC to 0.15 and
The warning angle (
maximum line power is assumed to be 200 MVA. This corresponds to apparent impedance:
U
=
Z
S
EQUATION1976 V1 EN-US
Simplified, the example can be shown as a triangle, see figure 229.
IEC07000016 V1 EN-US
Figure 229: Simplified figure to derive StartAngle
angleStart
EQUATION1977 V2 EN-US
In case of minor damped oscillations at normal operation we do not want the protection to
start. Therefore we set the start angle with large margin.
Set StartAngle to 110°.
For the
the circuit breaker.
Application manual
j 0.3
= =
j 0.15 pu 0.15 90
2.0
AnglePhi to 90°.
StartAngle ) should be chosen not to cross into normal operating area. The
2 2
20
= =
2 ohm
200
X
ZA
ZB
ZB ZA
³
arctan + arctan
Zload Zload
TripAngle it is recommended to set this parameter to 90° to assure limited stress for
Ð
o
pu
Zload
0.25 0.19
=
arctan + arctan = 7.1 + 5.4
2 2
Impedance protection
en07000016.vsd
0 » 0
13
Section 7
(Equation 420)
(Equation 421)
R
(Equation 422)
369