ZA
ZB
Zload
R
X
en07000016.vsd
IEC07000016 V1 EN-US
Figure 242: Simplified figure to derive StartAngle
0 0
arctan arctan arctan + arctan = 7.1 + 5.4
0.25 0.19
13
2 2
³ = »
ZB ZA
angleStart +
Zload Zload
EQUATION1977 V2 EN-US (Equation 411)
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 mar
gin.
Set StartAngle to 110°.
For the TripAngle it is recommended to set this parameter to 90° to assure limited
stress for the circuit breaker.
If the centre of pole slip is within the generator block set N1Limit to 1 to get trip at first
pole slip.
If the centre of pole slip is within the network set N2Limit to 3 to get enable split of the
system before generator trip.
Section 8 1MRK 504 163-UUS A
Impedance protection
480 Transformer protection RET670 2.2 ANSI
Application manual
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