5.17
Date Code 20060320 Instruction Manual SEL-311C Relay
Trip and Target Logic
Weak-Infeed Logic and Settings
q Figure 5.10; w Figure 5.1.
Figure 5.7 Permissive Input Logic Routing to Trip Logic
Variations for
Permissive
Underreaching
Transfer Trip (PUTT)
Scheme
Refer to Figure 5.4 and Figure 5.6. In a PUTT scheme, keying is provided by
Level 1 underreaching elements (fixed direction forward), instead of with
Relay Word bit KEY. This is accomplished by setting the output contact used
to key permissive trip, OUT105 for example, with these elements:
M1P Zone 1 phase distance instantaneous element
Z1G Zone 1 ground distance instantaneous element
67G1 Zone 1 directional residual ground instantaneous overcurrent
element
67Q1 Zone 1 directional negative-sequence instantaneous overcurrent
element
instead of with element KEY (see Figure 5.8):
OUT105 = M1P + Z1G + 67G1 + 67Q1 (Note: only use enabled elements)
If echo keying is desired, add the echo key permissive trip logic output, as
follows:
OUT105 = M1P + Z1G + 67G1 + 67Q1 + EKEY
In a three-terminal line scheme, another output contact (e.g., OUT107) is set the
same as OUT105 (see Figure 5.9).
Installation
Variations
Figure 5.9 shows output contacts OUT105 and OUT107 connected to separate
communications equipment, for the two remote terminals. Both output
contacts are programmed the same (OUT105 = KEY and OUT107 = KEY).
Depending on the installation, perhaps one output contact (e.g., OUT105 =
KEY) could be connected in parallel to both transmitter inputs (TX) on the
communications equipment in Figure 5.9. Then output contact OUT107 can be
used for another function.
Relay
Word
Bit
PTRX1
ECOMM = DCUB2
Relay
Word
Bits
PTRX
to TRIP
Logic
w
Setting
PTRX2
ECOMM = DCUB1
Setting
ECOMM = POTT
PT1
q
Setting
SELOGIC
Setting
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