5-10 Trip and Target Logic Date Code 990215
SEL-351P Manual Técnico
ECOMM = DCUB2 (DCUB scheme for three-terminal line [communications from
two
remote terminals])
ECOMM = DCB (DCB scheme)
These tripping schemes can all work in two-terminal or three-terminal line applications. The
DCUB scheme requires separate settings choices for these applications (ECOMM = DCUB1 or
DCUB2) because of unique DCUB logic considerations.
In most cases, these tripping schemes require (see
Figure SECTION 5: .4):
• Level 1 underreaching overcurrent elements set direction forward (setting DIR1 = F)
• Level 2 overreaching overcurrent elements set direction forward (setting DIR2 = F)
• Level 3 overcurrent elements set direction reverse (setting DIR3 = R)
See Settings in the Directional Control Settings subsection in Section 4: Loss-of-Potential,
Load Encroachment, and Directional Element Logic for more information on level direction
settings DIR1 through DIR4.
POTT, PUTT, DCUB, and DCB communications-assisted tripping schemes are explained in
subsections that follow.
Note: EZ settings should be turned off for the setting group(s) used in a communica-
tions-assisted tripping scheme. The overcurrent element applications for traditional
recloser control schemes (addressed with EZ settings) differ from those in a communica-
tions-assisted tripping scheme (see following trip settings). See Table 1.1 and 1.2 and the
EZ settings explanation preceding Table 1.1 in Section 1: Factory-Set Logic for more
information on EZ settings and overcurrent element applications for traditional recloser
control schemes.
Trip Setting TRCOMM
The POTT, PUTT, DCUB, and DCB tripping schemes use SEL
OGIC
Control Equation trip
setting TRCOMM for those tripping elements that are supervised by the communications-
assisted trip logic (see top half of
Figure SECTION 5: .1). Setting TRCOMM is typically set
with Level 2 overreaching overcurrent elements (set direction forward):
67P2 Level 2 directional phase instantaneous overcurrent element
67N2 Level 2 directional neutral ground instantaneous overcurrent element
67G2 Level 2 directional residual ground instantaneous overcurrent element
67Q2 Level 2 directional negative-sequence instantaneous overcurrent element
The exception is a DCB scheme, where Level 2 overreaching overcurrent elements (set direction
forward) with a short delay are used instead:
67P2S Level 2 directional phase instantaneous overcurrent element (with delay 67P2SD)
67N2S Level 2 directional neutral ground instantaneous overcurrent element (with delay
67N2SD)
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