Schweitzer Engineering SEL-351P - Trip Settings TRSOTF and TR; Trip Setting DTT; Use Existing SEL-321 Relay Application Guides for the SEL-351 P Recloser Control

Date Code 990215 Trip and Target Logic 5-11
SEL-351P Manual Técnico
67G2S Level 2 directional residual ground instantaneous overcurrent element (with delay
67G2SD)
67Q2S Level 2 directional negative-sequence instantaneous overcurrent element (with
delay 67Q2SD)
The short delays provide necessary carrier coordination delays (waiting for the block trip signal).
Trip Settings TRSOTF and TR
In a communications-assisted trip scheme, the SEL
OGIC Control Equation trip settings TRSOTF
and TR can also be used, in addition to setting TRCOMM.
Setting TRSOTF can be set as described in preceding subsection Switch-Onto-Fault (SOTF)
Trip Logic.
Setting TR is typically set with unsupervised Level 1 underreaching overcurrent elements (set
direction forward):
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
and other time delayed elements (e.g., Level 2 definite-time overcurrent elements).
Trip Setting DTT
The DTT and DUTT tripping schemes are realized with SEL
OGIC Control Equation trip setting
DTT, discussed at the beginning of this section.
To illuminate an LED to indicate a communications-assisted trip (via SEL
OGIC Control Equation
settings TRCOMM or DTT), reprogram an LED with Relay Word bit COMMT (see Figure 5.1).
The LED also has to be set as a trip-latch LED (see Front-Panel Status and Trip Target LEDs
subsection in Section 1: Factory-Set Logic).
Use Existing SEL-321 Relay Application Guides for the SEL-351P Recloser Control
The communications-assisted tripping schemes settings in the SEL-351P are very similar to those
in the SEL-321 Relay. Existing SEL-321 Relay application guides can also be used in setting up
these schemes in the SEL-351P. The following application guides are available from SEL:
AG93-06 Applying the SEL-321 Relay to Directional Comparison Blocking (DCB)
Schemes
AG95-29 Applying the SEL-321 Relay to Permissive Overreaching Transfer Trip
(POTT) Schemes
AG96-19 Applying the SEL-321 Relay to Directional Comparison Unblocking
(DCUB) Schemes
AG98-06 Using SEL-351s and SEL-351Rs to Provide Automated Load Restoration for
Distribution Feeders