Schweitzer Engineering Laboratories SEL-421-4 - Figure 6.28 500 Kv Power System; Out-Of-Step Logic Application Examples

6.119
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Applications Examples
Out-of-Step Logic Application Examples
Out-of-Step Logic Application Examples
The SEL-421 features OOS (out-of-step) logic for the following two functions:
➤ OSB (out-of-step blocking) logic blocks phase-distance elements and
Zone 1 ground-distance elements during power swings.
➤ OST (out-of-step tripping) logic trips the circuit breaker(s) during
unstable swings.
There are two application examples that explain how to apply OOS logic: an out-
of-step blocking scheme and an out-of-step tripping and blocking scheme. The
examples provide detailed setting procedures for a 5 A relay.
These examples are for three-pole tripping in a 500 kV power system. Applica-
tions for single-pole tripping are similar. Refer to Figure 6.28 for a one-line dia-
gram of the 500 kV system.
Z2GTSP Zone 2 Ground Distance Time Delay SPT (Y, N) N
67QGSP Zone 2 Dir. Negative-Sequence/Residual Overcur-
rent Single Pole Trip (Y, N)
N
TDUR1D SPT Min Trip Duration Time Delay
(2.000–8000 cycles)
6.000
TDUR3D 3PT Min Trip Duration Time Delay
(2.000–8000 cycles)
9.000
E3PT Three-Pole Trip Enable (SEL
OGIC Equation) 1
E3PT1 Breaker 1 3PT (SEL
OGIC Equation) 1
ER Event Report Trigger (SEL
OGIC Equation) R_TRIG Z2P OR
R_TRIG Z2G OR
R_TRIG 51S1 OR
R_TRIG Z3P OR
R_TRIG Z3G
Main Board (Outputs)
OUT101 (SELOGIC Equation) 3PT
OUT102 (SEL
OGIC Equation) KEY
a
Parameter n is 1 for BK1, 2 for BK2, and L for Line.
Table 6.31 Settings for 230 kV Parallel Cables Example (Sheet 5 of 5)
Setting Prompt Entry
Figure 6.28 500 kV Power System
SEL-421
Z
1L1
Z
1R
Z
1
S
S
R