Schweitzer Engineering Laboratories SEL-311C - Key Differences between the SEL-221 G and the SEL-311 C; Application Settings; Figure 14.1 SEL-221 G and SEL-311 C Out-Of-Step Characteristics

14 . 3
Date Code 20060320 Instruction Manual SEL-311C Relay
Application Settings for SEL-221 Series Relays
SEL-221G to SEL-311C Settings Conversion Guide
Key Differences
Between the
SEL-221G and the
SEL-311C
There are two key differences between the SEL-221G and the SEL-311C
when setting APP = 221G.
1. The SEL-221G setting 50L and Relay Word 50L supervise the
phase distance elements. In the SEL-311C, the phase
overcurrent supervision is fixed at 0.5 amps for 5 amp nominal
relays, and 0.1 amps for 1 amp nominal relays.
2. The SEL-221G uses a circular out-of-step characteristic
(Zone 4). The SEL-311C uses a quadrilateral out-of-step
characteristic (Zone 6). The Zone 6 reach is calculated from the
Zone 3 phase mho reach as shown in Figure 14.1.
Figure 14.1 SEL-221G and SEL-311C Out-of-Step Characteristics
Application Settings
From Access Level 2, set the SEL-311C application setting to “221G” as
shown below:
=>>SET APP TERSE <Enter>
Line Parameter Settings:
Application
(311C,221G,221G5,221H,221F,221F3,221C,221-16,2PG10)APP = 311C ? 221G <Enter>
Enable Settings:
Fault Location(Y,N) EFLOC = Y ? END <Enter>
Save Changes(Y/N)? Y <Enter>
Settings saved
=>>
Zone 6
Zone 5
Zone 3
0.5R
480
I
NOM
0.5R
R1
X1
0.5R
R
480
I
NOM
SEL-311C Out-of-Step CharacteristicSEL-221G Out-of-Step Characteristic
Zone 4 Diam. = 1.5 • Zone 3 Diam.
Zone 4
X1
R1
Zone 3