Permissive Underreach Transfer Trip (Putt) - ABB REL300 Instruction Manual

I.L. 40-385.7
plication, the Z3FR setting MUST be set to "REV" and Z3P, Z3G should be set to
100% of the line impedance.
f. Channel Simulation
The test function selection provides the capability to simulate the "TK" switch function for
keying action via OR-18 and AND-35 without the operation of pilot relay units, and to sim-
ulate the RS switch function for receiving of a trip or unblocking frequency signal action
without the operation from the remote transmitter.
g. Programmable Reclosing Initiation (Figure 3-19)
The basic programmable RI application is as described in Section 3.4.14. However, on pilot
systems, to activate the RI2 on any 3-pole high-speed trip, the external pilot enables switch
should be ON, and the PLT and PTRI should be set to YES. The operation will occur via
the logic AND-89, AND-84 and OR-84A (as shown in Figure 3-19).
3.5.2

Permissive Underreach Transfer Trip (PUTT)

The basic operating concepts of a PUTT scheme are:
1) Pilot relays (PLTP/PLTG) are set to overreach. The pilot channel is a frequency-shift type
device, and the transmitter frequency should be different at each terminal; its signal may
be passed through metallic wire or microwave.
2) Channel is normally operated with a guard frequency, the channel frequency will be shifted
from guard to trip when the Zone 1 reach relay (Z1P/Z1G) operates, and pilot trip is per-
formed when the pilot relay (PLTP and/or PLTG) operates, together with the receiving of a
carrier trip signal from the remote end.
PUTT includes the following logic: the functional display (STYP) should be set to PUTT
position.
a. Pilot Tripping Logic
The Pilot Tripping Logic for the PUTT scheme is exactly the same as for the POTT scheme
(Figures 3-21, 3-22, pages 3-42 & 3-43).
b. Carrier Keying Logic
(1)
(2)
The TBM logic is not required because the carrier keying units are set to underreach.
NOTE: For open breaker condition, the echo keying will not work due to lack of the "SEND"
signal from the remote terminal for an end zone fault. The remote terminal relies on
Zone 2 to clear the fault.
3-18
Forward fault keying (Figure 3-24, page 3-44)
For a forward end zone fault, the PUTT scheme will not key except when the internal
fault is within Zone 1. This means that the PUTT scheme keys only on Zone 1 faults.
Keying flows via AND-46, OR-18 and AND-35.
Signal continuation (Figure 3-23, page 3-43)
Same as for POTT scheme.