Sel 411L - Figure 3.102 Swing Center Voltage Slope Detection Logic

P.3.165
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Out-of-Step Logic (Zero Settings)
Figure 3.102 Swing Center Voltage Slope Detection Logic
The bottom input of AND Gate AND 5 asserts when the following is true.
➤ The absolute value of the SCV1 is above 0.05 and
➤ The enable out-of-step setting (EOOST) is either I, O, or C and
the positive-sequence impedance is in Zone 7 (Z1ZN7) or
➤ If out-of-step tripping is not selected (EOST = N), then the
following conditions must be true: the absolute value of the
SCV1 is below 0.85 and the positive-sequence impedance is in
the Starter Zone (Z1ZNS)
When AND Gate AND 5 asserts, SD asserts. When SD asserts, the Latch in
Figure 3.101 asserts, causing OSB_I and OSB to assert.
Figure 3.102 includes two checks for Z1, the positive-sequence impedance:
whether Z1 is in the Starter Zone (see Figure 3.103) and whether Z1 is in
Zone 7 (see Figure 3.96).
AND 1
AND 2
AND 3
AND 4
SD
AND 6
AND 5
–0.0172
dSCV1_F
–0.0026
dSCV1_S
dSCV1_F
0.0172
dSCV1_S
0.0026
OSB_I
Z2P
Z5P
Z4P
Z3P
| dSCV1_UF |
0.55
0.23
| d2SCV1_UF |
0.20
EOOST = I, O, C
Z1ZN7
0.85
| SCV1 |
Z1ZNS
| SCV1 |
0.05
Timer 1
1.75
0
CYC
Timer 2
Timer 3
Timer 4
5
0
CYC
1.75
0
CYC
5
0
CYC
Timer 5
0
0.5
CYC
OR 1