GE D90 Plus Instruction Manual page 356

CONTROL ELEMENTS
Zone 1 extension in the autoreclose scheme
Force three-pole tripping
Terminal manual close
346
Two approaches are available for implementation of zone 1 extension. The first method is
to operate normally from an under-reaching zone and use an overreaching distance zone
when reclosing the line with the other line end open. This method can be programmed via
the line pickup scheme.
A second method applies an over-reaching zone as long as the relay is ready to reclose,
then blocks this zone when reclosing. The autoreclose scheme provides an
operand that can be used to supervise the over-reaching zone or change to a
EXTEND
setting group where zone 1 is over-reaching.
The operand is set to logic 0 when autoreclose is in lockout or disabled
AR ZONE 1 EXTEND
and logic 1 when autoreclose is in reset. When extended zone 1 operand is logic 0, set the
distance functions to the normal under-reach zone 1 setting. When extended zone 1
operand is logic 1, the distance functions may be set to the extended zone 1 reach. During
a reclose cycle, the
AR ZONE 1 EXTEND
BREAKER signal is issued (AR SHOT COUNT > 0
returns to reset.
Figure 288: Autoreclose scheme zone 1 extension logic
AR LO
from autoreclose lockout logic
SHOT COUNT > 0
from autoreclose shot counter logic
AR ENABLED
from autoreclose enable logic
The reclosing scheme contains logic that is used to signal trip logic that three-pole tripping
is required for certain conditions. This signal is activated by any of the following conditions.
• The autoreclose scheme is paused after it was initiated.
• The autoreclose scheme is paused.
• The autoreclose scheme is in the lockout state.
• The autoreclose mode is programmed for three-pole operation.
• The shot counter is not at 0; that is, the scheme is not in the reset state. This ensures a
second trip will be three-pole when reclosing onto a permanent single phase fault.
• 1.25 cycles after the single-pole reclose is initiated by the AR 1P INIT signal.
Figure 289: Autoreclose force three-pole trip logic
The manual close logic receives the manual close signal from each of the breakers and
derives a manual close signal for the local terminal. The manual close is declared when:
• Breaker 1 issues a manual close and sequence 2 is not selected and breaker 2 is either
open or out-of-service.
operand goes to logic 0 as soon as the first CLOSE
operand) and remains at 0 until the recloser
FLEXLOGIC OPERAND
AR ZONE 1 EXTEND
OR
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
AR ZONE 1
870966A1.CDR