I.L. 40-386.4
2-11
2.4.13
Instantaneous Reverse Directional Overcurrent Ground (RDOG)
Similar to FDOG, the instantaneous reverse directional overcurrent ground function (RDOG) su-
pervises the ground units to prevent false tripping.
2.4.14
Programmable Reclose Initiation and Reclose Block Logic (Figure 2-18)
The REL301/302 system provides the following contact output for Reclosing Initiation and re-
closing block functions:
• RI2, used for Reclosing Initiation on trip
• RB, used for Reclosing Block
The operation of RI2 and RB contacts is controlled by the setting of the programmable Reclos-
ing Initiation logic. The operation of either RI2, or RB must be confirmed by the signal of TRSL,
which is the trip seal of REL301/302 operation.
The most common Reclosing Initiation practice is to have Reclosing Initiation on high speed (Pi-
lot, Zone-1 and high set overcurrent) trip only. On Pilot version programming can be accom-
plished by closing the EXT. (External) PILOT ENABLE switch and setting the “Pilot” to “YES”.
AND 84 will produce logic to operate the RI2 relay when receiving signals from TRSL and AND
89.
The program is further controlled by the “RI Type” setting:
“RI Type” setting
NO RI: 3PRN provides no output,
therefore, will not operate RI2.
“RI Type” setting
ØG RI:3PRN will provide output “1”
on single-phase-to-ground
fault only and will operate
RI2.
“RI Type” setting
ØØ, ØG, RI:3PRN will provide output “1”
on single- phase- to- ground
fault or 2-phase faults, and
will operate RI2.
“RI Type” setting
3Ø, ØØ, ØØG, ØG RI:
3PRN will provide output “1” on any
type of fault, and will operate RI2.
The Zone-1, Pilot and Highset overcurrent “Fast RI”, “Zone-2 RI” (Z2RI) and “Zone-3 RI”
(Z3RI) settings are provided for programming on applications where the Reclosing Initiation on
High-speed, Zone-2 or Zone-3 trips are desired. Logic AND 62A is controlled by the signal of
3PRN, therefore, the setting of “ØG RI”, “ØØ, ØG, RI” and “3Ø, ØØ, ØØG, ØØ RI” also affect
the Fast RI, Zone-2RI and Zone-3RI.
In general, the Reclosing Block (RB) relay will operate on TDT (Time Delay Trip) or OSB
(Out-of-Step Block condition). However, it will be disabled by the setting of Fast RI, Z2RI, and
Z3RI signal.