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HKB SINGLE POLE
The
back-up
relays
trip
all three
poles
types
of
faults
within
relays energize
the type MG relay (designated
)
MGT
which
in
turn
poles.
The
instantaneous
back-up
relays
are
TG-1 Time Delay
relay.
setting
of
5
to
15
energized
MGT
coil to
This
time
delay prcrvldes
the
carrier
relays to
fault is
single line to ground.
single pole relaying is out of service, a con
tact on
the
type W carrier switch shorts out
this time delay relay.
telephone
type relay designated X3 in the
A
type H�S relay is used to prevent the unfault
ed
trip circuits from being energized moment
arily
by the
transient response
H�S
element,
when
the
pears.
The
break
contact of
in
each
of
the
three
paths.
The
X3
contact
c�cles
and closes instantaneously.
tact does not open up the trip coil current on
the faulted
phase since
in previously.
The X3 relay as well as the types
relays
are energized
relay
trip
circuit thru the contactor switch
or when any one or two poles only are open.
The SGG
relay
shorts
ground back-up relay type CWC or CWP.
if the relay is set sensitively
necessary only
with a short time and might operate before the
opened
pha�e
reclosed.
is
relay
limits
the time
operated
with one or two phases open and thus
serves a back-up ground relay.
The operatim1
of
the
cuits are the
same as in the standard carrier
scheme.
Automatic
immediate
thru
high
speed breaker
pole
of the
breaker
three
poles open immediate
permitted depending
may
not be
The
reclosing scheme is shown on
conditions.
5, and operates
in
figure
either phase or ground
of the breaker for all
their range.
These
trips
the
three
phase
elements
of
the
connected
thru the type
This relay has a time
cycles after
which it
trip
all
1:hree poles.
an opportunity for
trip
one pole if the
When carrier
of the type
fault current disap
is connected
X3
phase-�elector
trip
opens
in about
3-4
This con
this has been sealed
SGG
and
JD
either
by the type
HKB
out the coils of the
This is
The type
timing
JD
which the line can
carrier control cir
reclosing is
provided
switches
after one
is
opened, but
if all
reclosure
may or
system
upon
as follows:
For
a phasc;
A-to-ground fault which trips phase
pole, the
high
will close
to
immediately reclose this pole.
The breaker auxiliary closing relay closes its
contact
52X
to energize 79X-0 coil.
the
operating coil
the type
SGR-12 reclosing relay.
in
the closing circuit is thus opened to pre
vent
further
reclosing
contact
on the toggle element, 79X, is closed
to
en�gize the reset motor (79M) of the type
SGR-12 relay when the breaker pole
indicated
by
the
breaker
stays
closed
after a suitablA delay to energize the
closes
toggle relay reset
sets
the
two 79X
energizes
the
timing motor
closing circuit for a subsequent trip.
A similar
sequence
place
for
the
other breaker poles when they
are
opened
by
operation
relays.
It is
to
control
switch
and
energize
a master
contacts
on MGT
79X-O of the type SGR-12 recloser to
and block reclosure until
poles
are
manually
also blocked when carrier is out of service by
the type
W carrier switch.
reclosing
is
to
phase
faults tripped by carrier, then another
type MG
relay
is
energized by CSl contactor
HZM-3 relay.
This type MG �elay will trip all
three breaker
poles and
out
and block
recloser of all
oe
poles.
The manual
closing
a
master closing relay designated MG-Cl.
contacts
of this
circuit of each of the three poles.
In the above
discussion it was assumed that
the
breaker
poles
first reclosure indicating
not
permanent.
fault is
solid, then
will
operate
to
again.
This
time
closing
contacts of
I.L. 41-600.7
speed breaker
switch
This is
of the
toggle element in
Contact 79X
of
pole A.
Another
closes
closing
of
52a.
If
the
motor contact 79M
coil 79X-O.
This coil re
contacts which in turn de
and
resets
of operations will take
of
the
protected
be
noted
that the manual
the back-up
relays
tripping
relay MGT.
operate
the
toggle element
lock out
after
the
breaker
reclosed.
Reclosing
If
instantaneous
be
prevented
for internal
required.
This
relay
switch of the t�e
energize 7�X to lock
thrAe breaker
switch, 101-C, operates
relay energize the
closing
remained closed after the
that the fault was
If
the
arc restrikes or the
the
protective
retrip
the
breaker
one or more of the 79X re
the type SGR-12 recloser
A
52bb,
as
the
the
all
Make
is
is
The
relays
poles
3
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