Schweitzer Engineering SEL-351P - Use Existing SEL-321 Relay DCUB Application Guide for the SEL-351 P Recloser Control; External Inputs; LOG1, LOG2 - Loss-Of-Guard Signal(S); PT1, PT2 - Received Permissive Trip Signal(S)

Date Code 990215 Trip and Target Logic 5-19
SEL-351P Manual Técnico
DCUB2 directional comparison unblocking scheme for three-terminal line
(communications from two
remote terminals)
The DCUB logic in
Figure SECTION 5: .10 takes in the loss-of-guard and permissive trip
outputs from the communication receivers (see
Figure SECTION 5: .12 and Figure SECTION 5:
.13) and makes permissive (PTRX1/PTRX2) and unblocking block (UBB1/UBB2) logic output
decisions.
DCUB schemes are typically implemented with FSK (frequency shift carrier) or analog
microwave as the communications medium.
Use Existing SEL-321 Relay DCUB Application Guide for the SEL-351P Recloser Control
Use the existing SEL-321 Relay DCUB application guide (AG96-19) to help set up the SEL-
351P in a DCUB scheme (see preceding subsection Communications-Assisted Trip Logic -
General Overview for more setting comparison information on the SEL-321/SEL-351Ps).
External Inputs
See Optoisolated Inputs in Section 7: Inputs, Outputs, Timers, and Other Control Logic for
more information on optoisolated inputs.
PT1, PT2 – Received Permissive Trip Signal(s)
In two-terminal line DCUB applications (setting ECOMM = DCUB1), a permissive trip signal is
received from one
remote terminal. One optoisolated input on the SEL-351P (e.g., input IN104)
is driven by a communications equipment receiver output (see
Figure SECTION 5: .12). Make
SEL
OGIC Control Equation setting PT1:
PT1 = IN104 (two-terminal line application)
In three-terminal line DCUB applications (setting ECOMM = DCUB2), permissive trip signals
are received from two
remote terminals. Two optoisolated inputs on the SEL-351P (e.g., inputs
IN104 and IN106) are driven by communications equipment receiver outputs (see
Figure
SECTION 5: .13). Make SEL
OGIC Control Equation settings PT1 and PT2 as follows:
PT1 = IN104 (three-terminal line application)
PT2 = IN106
SEL
OGIC Control Equation settings PT1 and PT2 are routed into the DCUB logic in Figure
SECTION 5: .10 for “unblocking block” and “permissive trip receive” logic decisions.
As explained in the preceding POTT subsection, the SEL
OGIC Control Equation settings PT1 and
PT2 in
Figure SECTION 5: .5 are routed in various combinations to control Relay Word bit PT,
depending on enable setting ECOMM = DCUB1 or DCUB2. Relay Word bit PT is then an input
into the POTT logic in
Figure SECTION 5: .6 (for echo keying).
LOG1, LOG2 – Loss-of-Guard Signal(s)
In two-terminal line DCUB applications (setting ECOMM = DCUB1), a loss-of-guard signal is
received from one
remote terminal. One optoisolated input on the SEL-351P (e.g., input IN105)