GE LPS-O - Page 37

GE Power Management LPS-O Line Protection System 1-
23
1 PRODUCT DESCRIPTION 1.9 OUT-OF-STEP TRIPPING
1
Figure 1–9: OST MHO CHARACTERISTIC
Figure 1–10: OUT-OF-STEP TRIPPING LOGIC DIAGRAM
The discrimination between a fault condition and a system swing is accomplished by checking the time
required for the apparent impedance to move from the load condition (far outside the OUTER characteristic) to
a point within the INNER characteristic. This change occurs immediately for a fault condition, but occurs at a
much slower rate for a swing.
Outer
Middle
Inner
Swing Line
R
X
Zf
Zr
OUTER
MIDDLE
INNER
NUMBRCHAR
=
2
NUMBRCHAR
=
2
TRIP OUT
TRIP IN
TLOS1
TLOS2
TLOS3
TLOS4
61
62
63
63
65
70
65
63
64
62
61
61
66
62
64
68
A = 1 - 100 ms
OST
A
A
A
0
A
A
0
A
0
Figure 1-17 Out-of-Step Tripping Logic Diagram
(REF.)
OUTER
MIDDLE
INNER
NUMBRCHAR
=
2
NUMBRCHAR
=
2
TRIP OUT
TRIP IN
TLOS1
TLOS2
TLOS3
TLOS4
61
62
63
63
65
70
65
63
64
62
61
61
66
62
64
68
A = 1 - 100 ms
OST
A
A
A
0
A
A
0
A
0
Fi
g
ure 1-17 Out-o
f
-Ste
p
Tri
pp
in
g
Lo
g
ic Dia
g
ram
(REF.)