Schweitzer Engineering SEL-351P - Use Existing SEL-321 Relay DCB Application Guide for the SEL-351 P Recloser Control

5-24 Trip and Target Logic Date Code 990215
SEL-351P Manual Técnico
Figure SECTION 5: .12: SEL-351P Recloser Control Connections to Communications
Equipment for a Two-Terminal Line DCUB Scheme (setting
ECOMM = DCUB1)
Figure SECTION 5: .13: SEL-351P Recloser Control Connections to Communications
Equipment for a Three-Terminal Line DCUB Scheme (setting
ECOMM = DCUB2)
D IRECTIONAL C OMPARISON B LOCKING (DCB) L OGIC
Enable the DCB logic by setting ECOMM = DCB. The DCB logic in Figure SECTION 5: .14
performs the following tasks:
• Provides the individual carrier coordination timers for the Level 2 directional overcurrent
elements 67P2S, 67N2S, 67G2S, and 67Q2S. These delays allow time for the block trip
signal to arrive from the remote terminal.
• Instantaneously keys the communications equipment to transmit block trip for reverse faults
and extends this signal for a settable time following the dropout of all Level 3 directional
overcurrent elements 67P3, 67N3, 67G3, and 67Q3.
• Latches the block trip send condition by the directional overcurrent following a close-in
zero-voltage three-phase fault where the polarizing memory expires. Latch is removed when
the polarizing memory voltage returns or current is removed.
• Extends the received block signal by a settable time.
Use Existing SEL-321 Relay DCB Application Guide for the SEL-351P Recloser Control
Use the existing SEL-321 Relay DCB application guide (AG93-06) to help set up the SEL-351P
in a DCB scheme (see preceding subsection Communications-Assisted Trip Logic – General
Overview for more setting comparison information on the SEL-321/SEL-351P).