0
200
400
600
800
1000
1200
1400
-4
-3
-2
-1
0
1
2
3
4
Time in milliseconds
→
Im
pedan
ce
Z
in
O
hm
and
ro
to
r ang
le
in
rad
ian
→
|Z| in Ohms
angle in rad
normal
load
fault 500 ms
Z(R,X) crossed
the impedance line, Z-line,
connecting points SE - RE
fault
occurrs
Z(R, X) under fault lies
on the impedance line
or near (for 3-ph faults)
Under 3-phase fault
condition rotor angle
of app. ±180 degrees
is measured ...
rotor (power)
angle
|Z|
IEC10000110-1-en.vsd
IEC10000110 V1 EN
Figure 77:
Rotor (power) angle and magnitude of the complex impedance Z(R, X)
against the time
In order to be able to fully understand the principles of OOSPPAM (78), a stable case, that
is, a case where the disturbance does not make a generator to go out-of-step, must be
shown.
1MRK 502 048-UUS A
Section 7
Impedance protection
179
Technical manual
