ABB 650 series, Technical Manual

Page: 163 / 778

The tP1 timer in figure 63 serve as detection of initial power swings, which are usually not
as fast as the later swings are. The tP2 timer become activated for the detection of the
consecutive swings, if the measured impedance exit the operate area and returns within the
time delay, set on the
tW waiting timer. The upper part of figure 63 (internal input signal
ZOUT_A, ZIN_A, AND-gates and tP-timers) are duplicated for phase B and C. All tP1
and tP2 timers in the figure have the same settings.
ANSI05000113-2-en.vsd
AND
ZINA
AND
DET-A
OR
AND
AND
ZOUTA
-loop
ZOUTB
ZOUTC
OR
detected
OR
-loop
0-tP1
0
0-tP2
0
0
0-tW
ANSI05000113 V2 EN
Figure 63: Detection of power swing in phase A
1MRK 502 048-UUS A
Section 7
Impedance protection
157
Technical manual