Schweitzer Engineering Laboratories SEL-351A - Figure 4.6 Internal Enables (32 QE and 32 QGE) Logic for Negative-Sequence Voltage-Polarized Directional Elements

4.18
SEL-351A Relay Instruction Manual Date Code 20080213
Loss-of-Potential, Load Encroachment, and Directional Element Logic
Directional Control for Neutral-Ground and Residual-Ground Overcurrent Elements (Not in SEL-351A-1)
In most communications-assisted trip schemes, the levels are set as follows:
➤ Level 1 overcurrent elements set direction forward (DIR1 = F)
➤ Level 2 overcurrent elements set direction forward (DIR2 = F)
➤ Level 3 overcurrent elements set direction reverse (DIR3 = R)
If a level direction setting (e.g., DIR1) is set:
DIR1 = N (nondirectional)
then the corresponding Level 1 directional control outputs in Figure 4.17 and
Figure 4.18 assert to logical 1. The referenced Level 1 overcurrent elements in
Figure 4.17 and Figure 4.18 are then not controlled by the directional control
logic.
See the beginning of Directional Control Settings (Not in SEL-351A-1) on
page 4.38 for discussion of the operation of level direction settings DIR1–
DIR4 when the directional control enable setting E32 is set to E32 = N.
In some applications, level direction settings DIR1–DIR4 are not flexible
enough in assigning the desired direction for certain overcurrent elements.
Directional Control Provided by Torque Control Settings (Not in SEL-351A-1)
on page 4.57 describes how to avoid this limitation for special cases.
q From Figure 4.1; w from Figure 4.7; e to Figure 4.9 and Figure 4.20;
r to Figure 4.20 and Figure 4.21; t to Figure 4.9, Table 4.1, and Table 4 .2 .
Figure 4.6 Internal Enables (32QE and 32QGE) Logic for Negative-
Sequence Voltage-Polarized Directional Elements
NOTE: In the SEL-351A-1, Relay Word
bits 50QF and 50QR are set internally
and processed, even though group
settings 50QFP and 50QRP are
unavailable. See 50QFP and 50QRP
Set Automatically on page 4.43 for
internal setting values.
|3I
2
|
|I
2
|
a2 • |I
1
|
k2 • |I
0
|
|I
2
|
Setting
Settings
50QFP
50QRP
50QR
50QF
32VE
32IE
Setting
e
32QE
(Internal Enable)
r
"Q" Listed in
Setting ORDER
Setting Enable
t
32QGE
(Internal Enable)
(I
0
= I
G/3
)
q
w
LOP
ELOP = Y or Y1
Loss-of-Potential
Setting
VNOM = OFF
Relay
Word
Bits
Relay
Word
Bit
Relay
Word
Bits
Courtesy of NationalSwitchgear.com