Schweitzer Engineering SEL-351P - Variations for Permissive Underreaching Transfer Trip (PUTT) Scheme; Installation Variations

Date Code 990215 Trip and Target Logic 5-17
SEL-351P Manual Técnico
Figure SECTION 5: .7: Permissive Input Logic Routing to Trip Logic
Variations for Permissive Underreaching Transfer Trip (PUTT) Scheme
Refer to
Figure SECTION 5: .4 and Figure SECTION 5: .6. In a PUTT scheme, keying is
provided by Level 1 underreaching overcurrent elements (set direction forward), instead of with
Relay Word bit KEY. This is accomplished by setting output contact OUT105 with these
elements:
67P1 Level 1 directional phase instantaneous overcurrent element
67N1 Level 1 directional neutral ground instantaneous overcurrent element
67G1 Level 1 directional residual ground instantaneous overcurrent element
67Q1 Level 1 directional negative-sequence instantaneous overcurrent element
instead of with element KEY (see
Figure SECTION 5: .8):
OUT105 = 67P1 + 67N1 + 67G1 + 67Q1 (Note: only use enabled elements)
If echo keying is desired, add the echo key permissive trip logic output, as follows:
OUT105 = 67P1 + 67N1 + 67G1 + 67Q1 + EKEY
In a three-terminal line scheme, output contact OUT107 is set the same as OUT105 (see
Figure
SECTION 5: .9).
Installation Variations
Figure SECTION 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).