6.43
Date Code 20171006
Instruction Manual
SEL-400 Series Relays
Autoreclosing
Voltage Checks for Autoreclosing and Manual Closing
Voltage Checks for Autoreclosing and Manual Closing
Voltage elements are available for a final check of line and bus voltages before an
autoreclose or manual close is issued. These voltage elements and corresponding
pickup settings are enabled with Reclosing Voltage Check enable setting
EVCK := Y.
shows the application of these voltage elements and
shows their implementation. Check voltages for arrangements of as
many as two circuit breakers (Global setting NUMBK := 2), as shown in
. If the relay is only connected to a single breaker (Global setting
NUMBK := 1), then settings 27BK2P and 59BK2P and their associated elements
(LLDB2, DLDB2, and DLLB2) are not available.
and
come from corre-
sponding voltage source selection settings SYNCP, SYNCS1, and SYNCS2.
Review details of synchronism checking in the Protection section of the desired
product-specific Instruction Manual.
The pickup settings in
are made on the VP voltage base. VP is the
voltage reference for voltage angle and magnitude. Only voltage magnitude is of
concern for the settings in
, not voltage angle.
implies that three-phase voltage is available from the line PTs. But,
resultant voltage VP corresponds to only one phase of this three-phase voltage
(e.g., setting SYNCP = VAY; VP is the normalized voltage from voltage input
VAY). All the voltage elements in
are single-phase voltage elements,
detecting live or dead voltage on the bus side with a single-phase voltage ele-
ment, and likewise on the line side.
Whether or not synchronism-check logic is used, it still has to be enabled for the
respective breaker (E25BK1 := Y, Y1, or Y2 and E25BK2 := Y, Y1, or Y2) to
allow the corresponding voltage source selection settings (SYNCP, SYNCS1,
and SYNCS2) to be made.
Live Line/Live Bus
that live line/live bus is not available for either circuit
breaker. Voltage elements 59VP, 59VS1, and 59VS2, described in the
Section 5: Protection Functions
of the desired product-specific instruction man-
ual, are available for such a function (e.g., 59VP AND 59VS1 for live line/live bus 1).
Supervising Circuit Breaker Closing with Voltage Checks
Supervising Autoreclosing
, both breakers trip open and the lead breaker
recloses first. For example, presume the lead breaker closes only if its respective
bus is live and the line is dead (dead line/live bus; see
). Then, after
successful reclose of the lead breaker, the follower breaker closes on synchro-
nism check. Such reclose supervision logic is realized as follows for respective
breakers BK1 and BK2:
3P1CLS :=
LEADBK1 AND DLLB1 OR FOLBK1 AND 25A1BK1 OR …
3P2CLS :=
LEADBK2 AND DLLB2 OR FOLBK2 AND 25A1BK2 OR …
Summary of Contents for SEL-421-4
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