Loss-Of-Potential Supervision; Loss-Of-Current Monitoring; Overcurrent Supervision; Instantaneous Overcurrent Trip - ABB REL300 Instruction Manual

3.9 LOSS-OF-POTENTIAL SUPERVISION (LOP, See Section 3.4.3)
3.10 LOSS-OF-CURRENT MONITORING (LOI, See Section 3.4.4)
3.11 OVERCURRENT SUPERVISION (See Section 3.4.5)
3.12 INSTANTANEOUS OVERCURRENT TRIP (See Section 3.4.6)
3.13 HIGH-SET INSTANTANEOUS DIRECT TRIP, INCLUDING THREE-PHASE AND ONE GROUND
OVERCURRENT UNITS FOR SPT/3PT APPLICATION (See Section 3.4.6)
3.14 CLOSE-INTO-FAULT TRIP AND STUB BUS PROTECTION (See Section 3.4.7)
3.15 UNEQUAL-POLE CLOSING LOAD PICKUP LOGIC (See Section 3.4.8)
3.16 SELECTABLE LOSS-OF-LOAD ACCELERATED TRIP LOGIC (LLT) (See Section 3.4.9)
3.17 CURRENT CHANGE FAULT DETECTOR (See Section 3.4.10)
3.18 VOLTAGE CHANGE FAULT DETECTOR (See Section 3.4.10)
3.19 3-TERMINAL LINE APPLICATION
For a 3-terminal BLK application, since the frequency of the three transmitters are the same,
any one transmitter starting will block the pilot system from tripping, therefore, logic for the 3-
terminal BLK pilot system would be the same as that used for the 2-terminal BLK system.
However, for POTT/PUTT/UBLK systems, since the transmitter frequency is different at each
terminal, logic for the second receiver (RCVR-2) should be added to the system when the ap-
plication involves 3-terminals. Functional display "3TRM" should be set at "YES" position when
the 3-terminal line is applied.
a. Additional Logic For POTT and Simplified Unblocking (Figure 3-29, page 3-47)
This logic includes contact converters (CC) for RCVR-2, AND-55, and logic for the second
receive indication. The second receiver output operates the contact converter (or voltage).
Output of AND-55 provides carrier trip signal (CR) to satisfy AND-30 via AND-64 and allows
pilot tripping.
b. Additional Logic for PUTT (Figure 3-30, page 3-48)
The additional logic for this scheme would be similar to that as described for POTT scheme,
except logic includes AND-56, AND-57 and 50/ms timer. This is because only the Zone 1
reach relay keys the transmitter on internal faults. For a close-in Zone 1 fault, only the local
terminal can key its transmitter and the other two cannot. This logic provides a CR pilot trip
signal for 50 ms for system security. For a fault which can be detected by relays at two ter-
I.L. 40-385.7
3-23