Schweitzer Engineering Laboratories SEL-311L, Instruction Manual, Page: 123 / 734

Date Code 20011112 Line Current Differential, Distance, Out-of-Step, Overcurrent, 3-69
Voltage, Synchronism Check, and Frequency Elements
SEL-311L Instruction Manual
Table 3.11: Voltage Values Used by Voltage Elements
Voltage Description
V
A
A-phase voltage, from SEL-311L Relay rear-panel voltage input VA
V
B
B-phase voltage, from SEL-311L Relay rear-panel voltage input VB
V
C
C-phase voltage, from SEL-311L Relay rear-panel voltage input VC
V
AB
Calculated phase-to-phase voltage
V
BC
Calculated phase-to-phase voltage
V
CA
Calculated phase-to-phase voltage
3V
0
Residual voltage (VA + VB + VC)
V
2
Negative-sequence voltage
V
1
Positive-sequence voltage
V
S
Synchronism check voltage, from SEL-311L Relay rear-panel voltage input
VS—see note below.
Note: Voltage V
S
is used in the synchronism check elements described in the following
subsection Synchronism Check Elements . Voltage V
S
is also used in the three voltage
elements described at the end of Table 3.12 and in Figure 3.52. These voltage elements
are independent of the synchronism check elements, even though voltage V
S
is used in
both.
Voltage Element Settings
Table 3.12 lists available voltage elements and the corresponding voltage inputs and settings
ranges for the SEL-311L Relay (see Figure 1.4 for voltage input connection).
Table 3.12: Voltage Elements Settings and Settings Ranges
Voltage Element
(Relay Word bits) Operating Voltage Pickup Setting/Range See Figure
27A V
A
27P
27B V
B
OFF, 0.00–150.00 V secondary
27C V
C
3P27 27A * 27B * 27C
59A V
A
59P
59B V
B
OFF, 0.00–150.00 V secondary
59C V
C
3P59 59A * 59B * 59C
Figure 3.50