Schweitzer Engineering Laboratories SEL-311C - Use Existing SEL-321 Relay Application Guides for the SEL-311 C Relay

5.12
SEL-311C Relay Instruction Manual Date Code 20060320
Trip and Target Logic
Communications-Assisted Trip Logic-General Overview
Use Existing SEL-321
Relay Application
Guides for the
SEL-311C Relay
The communications-assisted tripping schemes settings in the SEL-311C are
very similar to those in the SEL-321 Relay. Existing SEL-321 application
guides can also be used in setting up these schemes in the SEL-311C. 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
The major differences are how the optoisolated input settings and the trip
settings are made. The following explanations describe these differences.
Optoisolated Input Settings Differences Between the SEL-321 and
SEL-311C Relays
The SEL-311C does not have optoisolated input settings like the SEL-321.
Rather, the optoisolated inputs of the SEL-311C are available as Relay Word
bits used in SEL
OGIC control equations. The following optoisolated input
setting example is for a Permissive Overreaching Transfer Trip (POTT)
scheme.
In the above SEL-311C setting example, Relay Word bit IN102 is set in the
PT1 SEL
OGIC control equation. Optoisolated input IN102 is wired to a
communications equipment receiver output contact. Relay Word bit IN102
can also be used in other SEL
OGIC control equations in the SEL-311C. See
Optoisolated Inputs on page 7.3 for more information on optoisolated inputs.
Trip Settings Differences Between the SEL-321 and SEL-311C Relays
Some of the SELOGIC control equation trip settings of the SEL-321 and
SEL-311C relays are not operationally different, just labeled differently. The
correspondence is:
The SEL-321 handles trip unlatching with setting TULO. The SEL-311C
handles trip unlatching with SEL
OGIC control equation setting ULTR.
The SEL-321 has single-pole trip logic. The SEL-311C does not have single-
pole trip logic.
SEL-321 Relay SEL-311C Relay Description
IN102 = PT PT1 = IN102 (received permissive trip)
SEL-321 Relay SEL-311C Relay Description
MTCS TRCOMM (Communications-Assisted Trip Conditions)
MTO TRSOTF (Switch-Onto-Fault Trip Conditions)
MTU TR (Unconditional or Other Trip Conditions)