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Angular frequency
(ω 0 )
x=1
Frequency (at x=0.6) (Hz)
Nominal (f0)
f0 – 0.5
f0 – 1.0
f0 – 1.5
f0 – 2.0
f0 – 2.5
f0 – 3.0
f0 – 3.5
Figure 2.19-6 Phenomenon of frequency drifting in Loss of synchronism
For the operation for the FRQ1, for example, the user should program to inject the block
signal to the connection point "FRQ1-BLOCK" (see Figure 2.19-2); set On for the [FRQ-RCD-
EN]. Similar approaches are also required for the other FRQ2–8 schemes.
Note: In the under-frequency phenomenon, blocking is not carried out if phase angle
changes rapidly. The FRQ trip can be permitted only for rapid phase angle change.
Electrical
center (x=0.5)
F(x=0.8)
F(x=0.6)
t
t
Tendency
Downing frequency
0
0.2
0.4
0.6
0.8
- 211 -
Angular frequency
(ω 0 +ω d )
x=0
F(x=0.4)
F(x=0.2)
t
t
Tendency
Rising frequency
Δf/Δt=1.0Hz/0.05sec
=20Hz/s
1.0
1.2
1.4
1.6
6F2T0207 (0.01)
1.8
2.0
time (sec)
GRE200 (5,6)
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