GE CEB52A User manual

GEK
-
1291
H
INSTRUCTIONS
OFFSET
MHO
DISTANCE
RELAY
TYPE
CEB
52
A
GENERAL
ELECTRIC
Courtesy of NationalSwitchgear.com

GEK
-
1291
CONTENTS
PAGE
INTRODUCTION
APPLICATION
CALCULATION
OF
SETTINGS
RATINGS
3
3
3
4
CONTACTS
TARGET
SEAL
-
IN
UNIT
OPERATING
PRINCIPLES
OM
UNIT
-
ZERO
OFFSET
CHARACTERISTICS
OM
UNIT
-
WITH
OFFSET
OM
UNIT
-
ZERO
OFFSET
IMPEDANCE
CHARACTERISTIC
DIRECTIONAL
ACTION
...
.
UNDERREACH
MEMORY
ACTION
TRANSIENT
OVERREACH
.
..
OPERATING
TIME
TAPPED
AUTOTRANSFORMER
5
5
6
6
6
6
6
6
7
7
7
8
8
8
BURDENS
9
CURRENT
CIRCUITS
POTENTIAL
CIRCUITS
CONSTRUCTION
RECEIVING
,
HANDLING
AND
STORAGE
ACCEPTANCE
TESTS
VISUAL
INSPECTION
MECHANICAL
INSPECTION
ELECTRICAL
CHECKS
-
OM
UNITS
ELECTRICAL
TESTS
-
TARGET
SEAL
-
IN
UNIT
INSTALLATION
PROCEDURE
LOCATION
MOUNTING
CONNECTIONS
VISUAL
INSPECTION
MECHANICAL
INSPECTION
PORTABLE
TEST
EQUIPMENT
OFFSET
CHECK
ELECTRICAL
TESTS
ON
THE
OM
UNITS
.
..
.
INSPECTION
MHO
UNITS
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
.
.
CONTACT
CLEANING
SERVICING
CONTROL
SPRING
ADJUSTMENTS
OHMIC
REACH
ADJUSTMENT
ANGLE
OF
MAXIMUM
TORQUE
RENEWAL
PARTS
9
9
10
10
11
11
11
11
14
14
14
14
14
14
14
14
14
15
16
17
17
17
17
18
18
18
18
Please
check
your
previous
revision
to
This
instruction
book
has
had
a
major
revision
,
compare
material
.
NOTE
:
2
Courtesy of NationalSwitchgear.com

GEK
-
1291
OFFSET
MHO
DISTANCE
RELAY
TYPE
CEB
52
A
INTRODUCTION
The
CEB
52
A
relay
is
;
a
three
-
phase
,
high
speed
,
single
zone
directional
mho
distance
phase
relay
with
provisions
for
offsetting
the
characteristic
a
fixed
amount
.
It
is
constructed
of
three
-
single
-
phase
units
in
one
L
2
-
D
case
with
facilities
for
single
-
phase
testing
.
One
target
and
seal
-
in
unit
provides
indication
of
operation
on
all
three
units
.
The
transient
over
-
reach
characteristics
of
the
CEB
52
A
relay
have
not
been
limited
to
the
point
where
it
is
suitable
for
use
as
a
first
zone
relay
.
This
relay
was
designed
primarily
for
use
as
a
carrier
starting
relay
in
directional
comparison
schemes
.
It
is
also
applicable
as
a
second
or
third
zone
relay
in
straight
distance
schemes
.
APPLICATION
The
CEB
52
A
was
specifically
designed
for
application
as
a
carrier
starting
relay
in
directional
comparison
relaying
schemes
.
To
serve
this
purpose
the
relay
is
equipped
with
normally
closed
contacts
as
well
as
with
normally
open
contacts
.
Since
many
originally
straight
distance
terminals
are
later
converted
to
directional
comparison
terminals
,
the
CEB
52
A
should
be
used
as
the
third
zone
relay
in
straight
distance
schemes
to
facilitate
any
future
conversion
.
The
offset
feature
should
always
be
used
when
the
relay
is
employed
to
start
the
carrier
or
when
it
is
required
to
operate
in
conjunction
with
some
time
delay
for
zero
voltage
faults
.
In
carrier
starting
applications
the
normally
closed
contacts
are
closed
under
normal
conditions
to
hold
off
carrier
.
When
line
side
potentials
are
employed
,
and
the
line
is
deenergized
,
the
relay
will
have
no
electrical
restraint
and
will
depend
on
the
control
spring
to
provide
sufficient
contact
pressure
to
keep
carrier
turned
off
.
It
is
for
this
reason
that
this
relay
has
a
relatively
strong
spring
setting
.
Figs
.
5
and
6
give
the
operating
characteristics
for
this
relay
with
the
strong
spring
setting
,
with
and
without
offset
.
When
the
relay
is
employed
with
bus
potentials
,
or
if
it
is
used
in
straight
distance
schemes
,
a
weaker
spring
setting
may
be
employed
.
The
section
under
SERVICING
describes
how
the
spring
setting
can
be
changed
.
Figs
.
7
and
8
give
the
operating
characteristics
for
the
weaker
spring
setting
with
and
without
offset
.
The
CEB
52
A
will
be
calibrated
in
the
factory
with
the
strong
setting
.
The
CEB
52
A
relay
and
its
comparison
zone
packaged
relays
may
be
combined
in
several
different
ways
for
use
in
straight
distance
and
directional
comparison
relaying
schemes
.
Fig
.
17
illustrates
how
the
CEY
51
A
,
CEY
52
A
,
and
CEB
52
A
relays
plus
the
RPM
21
D
timing
relay
may
be
employed
for
three
zone
directional
distance
protection
of
transmission
circuits
against
all
multi
-
phase
faults
.
Separate
ground
fault
relays
are
required
for
single
-
phase
-
to
-
ground
faults
.
Fig
.
18
shows
how
these
same
distance
relays
plus
a
SAM
16
A
static
timing
relay
and
the
necessary
ground
and
auxiliary
relays
are
combined
in
a
directional
comparison
relaying
scheme
.
The
section
under
CALCULATION
OF
SETTINGS
provides
a
typical
worked
example
covering
the
setting
of
this
relay
.
CALCULATION
OF
SETTINGS
Consider
one
terminal
of
a
two
terminal
69
KV
transmission
line
,
17.3
miles
long
having
a
phase
-
to
-
neutral
impedance
of
Z
.
=
0.14
+
j
0.80
ohms
per
mile
prim
°
K
Z
=
17.3
(
0.14
+
j
0.80
)
=
2.4
+
13.9
ohms
total
These
instructions
do
not
purport
to
cover
all
details
or
variations
in
equipinent
nor
to
provide
for
every
possible
contingency
to
be
met
in
connection
with
installation
,
operation
or
maintenance
.
further
information
be
desired
or
should
particular
problems
arise
which
are
not
covered
sufficiently
for
the
purchaser
'
s
purposes
,
the
matter
should
be
referred
to
the
General
Electric
Company
.
To
the
extent
required
the
products
described
herein
meet
applicable
ANSI
,
but
no
such
assurance
is
given
with
respect
to
local
codes
and
ordinances
because
they
vary
greatly
.
Should
IEEE
and
NEMA
standards
;
3
Courtesy of NationalSwitchgear.com

GEK
-
1291
PT
Ratio
=
69
,
000
/
116
=
600
/
1
CT
Ratio
=
600
/
5
=
120
/
1
CT
Ratio
Zsec
^
prim
PT
Ratio
120
=
(
2.4
+
j
13.9
)
Z
=
0.48
+
j
2.78
ohms
sec
600
=
2.82
Z
_
80.2
°
ohms
Z
sec
Assume
that
the
CEB
52
A
is
to
be
used
to
provide
third
zone
protection
in
the forward
direction
and
it
is desired
to
set
the forward reach
for
6.0
ohms
at
an
angle
of
80.2
degrees
.
This
setting
having
been
arrived
at
after
due
consideration
to
coordinate
with
the
phase
relays
on
adjacent
circuits and
taking
current
infeed
into
account
.
Case
I
-
No
offset
required
With
the
angle
of
maximum
torque
of
the
relay
at
75
degrees
,
the
percent
tap
setting
required
is ob
-
tained
from
the
following
equation
.
100
(
3.0
)
Cos
(
80.2
-
75
)
Output
Tap
=
6.00
=
49.8
percent
Set
the
output
tap
at
50
percent
.
Case
II
-
Offset
required
Since
the
offset
setting
is
along
the
reactance
axis
on
the
R
-
X
diagram
,
it
is
easiest
to
arrive
at
the
proper
tap
setting
by
means
of
a
graphical
solution
as
outlined
below
.
1
.
Draw
the
R
-
X
diagram
as
in
Fig
.
2
.
Draw
line
0
A
at
the
impedance
angle
of
the line
and
measure
off
the
length
to
be
protected
.
In
this
case
it
is
6.0
ohms
.
Through
the
point
S
,
representing
the
offset
,
which
in
this
case
is
(
R
=
0
,
X
,
=
0.5
)
,
draw
the
line
BC
at
the
angle
of
maximum
torque
for
which
the
relay
is
set
.
In
this
case
it
is
75
degrees
.
By
trial
and
error
draw
a
circle
which
has its
center
on
line
BC
and
which
passes
through
both
points
P
and
S
.
This
circle
represents
the
desired
setting
.
Measure
the
diameter
of
the
circle
SM
.
In
this
case
it
measures
6.55
ohms
.
The
desired
OUTPUT
TAP
setting
in
percent
is
given
by
the
following
equation
:
(
100
)
(
Minimum
Reach
)
2
.
3
.
4
.
5
.
6
.
Output
Tap
=
Desired
Diameter
(
100
)
(
3.0
)
Output
Tap
=
45.8
6.55
Set
the
OUTPUT
TAP
for
46
percent
.
RATINGS
The
type
CEB
52
A
relays
covered
in
these
instructions
are
available with
ratings
given
in
Table
I
.
4
Courtesy of NationalSwitchgear.com

GEK
-
1291
TABLE
I
(
Volts
)
(
Hertz
)
(
Amperes
)
120 120
120
120
120
Rated
Voltage
Rated
Frequency
Rated
Current
Basic
Ohm
Reach
Taps
Offset
Ohm
Tap
Angle
of
Max
.
Torque
*
*
One
Second
Rating
(
Offset
Out
)
(
Amps
)
One
Second
Rating
(
Offset
In
)(
Amps
)
60
60
60
50
60
5.0
5.0
5.0
5.0
5.0
1
/
2
/
3
2
/
4
/
6
1
/
2
/
3
1
/
2
/
3
0.5
/
1.0
/
1.5
0.5
0.5
0.20
0.5
0.25
75 75
75
75
75
260
1.45
260
260
260
145
225
90
90
145
**
The
angle
of
maximum
torque
can
be
adjusted
to
60
degrees
lag
with
the
connections
shown
in
^
21
f
°
r
the
top
unit
,
R
22
for
the
middle
unit
and
R
23
for
the
bottom
unit
,
but
the
reach
at
the
60
degree
setting
will
be
20
percent
less
than
the
reach
at
the
75
degree
setting
.
It
will
be
noted
that
three
basic
minimum
reach
settings
are
listed
for
the
OM
units
.
Selection
of
the
desired
basic
minimum
reach
setting
for
each
unit
is
made
by
means
of
links
on
a
terminal
board
located
at
the
back
of
the
realy
(
see
Fig
.
2
)
.
The
position
of
the
two
sets
of
links
,
(
for
each
unit
)
,
each
identified
as
A
-
B
determines
the
basic
minimum
setting
of
the
mho
units
.
The
basic
minimum
reach
setting
=
(
A
+
B
)
line
settings
.
The
ohmic
reach
of
the
OM
units
can
be
adjusted
in
one
percent
steps
over
a
10
/
1
range
for
any
of
the
basic
minimum
reach
settings
listed
in
Table
II
by
means
of
autotrans
-
former
tap
leads
on
the
tap
blocks
at
the
right
side
of
the
relay
.
The
OM
units
may
be
offset
.
Selection
of
either
zero
or
0.5
ohms
offset
is
made
by
means
of
links
on
terminal
boards
located
on
the
rear
of
the
relay
.
Fig
.
13
and
by
adjusting
CONTACTS
The
contacts
of
the
CEB
52
A
relay
will
close
and
carry
momentarily
30
amperes
DC
.
However
,
the
circuit
breaker
trip
circuit
must
be
opened
by
an
auxiliary
switch
contact
or
other
suitable
means
since
the
relay
contacts
have
no
interrupting
rating
.
TARGET
SEAL
-
IN
UNIT
The
target
seal
-
in
unit
used
in
the
CEB
52
A
relays
has
ratings
as
shown
in
Table
II
.
TABLE
II
TARGET
SEAL
-
IN
UNIT
0.6
2.0
0.2
2.0
Pickup
Rating
2.0
0.2
0.6
2.0
Tap
Used
Carry
30
amps
for
(
sec
)
Carry
10
amps
for
(
sec
)
Carry
continuously
(
amp
)
Minimum
operating
(
amp
)
Minimum
drop
-
out
(
amp
)
DC
resistance
(
ohms
)
60
Hz
impedance
(
ohms
)
50
Hz
impedance
(
ohms
)
3.5
0.5
0.05
2.2
30
5.0
0.45
20
2.6
1.2
0.37
2.3
2.0
0.6
0.2
2.0
0.5
0.15
0.05
0.5
0.18
0.78
8.3
0.24
0.65
6.2
50
0.65
0.54
5.1
42
0.54
2.5
amps
@
125
VDC
2.5
amps
@
175
VDC
DC
resistive
Interrupting
Rating
(
amps
)
5
Courtesy of NationalSwitchgear.com

GEK
-
1291
OPERATING
PRINCIPLES
OM
UNIT
-
ZERO
OFFSET
The
OM
units
of
the
CEB
52
A
relay
are
of
the
four
pole
induction
cylinder
construction
in
which
torque
is
produced
by
the
interaction
between
a
polarizing
flux
or
fluxes
proportional
to
the
restraining
or
operating
quantities
.
The
schematic
connections
of
the mho
unit
are
shown
in
Fig
.
3
.
The
two
side
poles
,
energized
by
phase
-
to
-
phase
voltage
,
produce
the
polarizing
iflux
.
The
flux
in
the
front
pole
,
which
is
energized
by
a
percentage
of
the
same
phase
-
to
-
phase
voltage
,
interacts
with
the
polarizing
flux
to
produce
restraint
torque
.
The
flux
in
the
rear
pole
,
which
is
energized by
the
two
line
currents
associated
with
the
same
phase
-
to
-
phase
voltage
,
interacts
with
the
polarizing
flux
to
produce
operating
torque
.
The
torque
at
the
balance
point
of
the
unit
can
therefore
be
expressed
by
the
following
equation
:
Torque
=
0
=
El
cos
(
0
-
9
)
-
KE
^
(
2
)
where
:
E
=
phase
-
to
-
voltage
(
E
12
)
I
=
delta
current
(
Ij
-
I
2
)
0
=
angle
of
maximum
torque
of
the unit
0
=
power
factor
angle
of
fault
impedance
K
=
design
constant
To
prove
that
equation
(
2
)
defines
a
mho
characteristic divide both
sides
by
E
^
and
transpose
,
equation
reduces
to
:
The
1
—
cos
(
0
-
0
)
=
K
Z
or
:
Y
cos
(
0
-
0
)
=
K
Thus
,
the
unit
will
pick
up
at
a
constant
component
of
admittance
at
a
fixed
angle depending
on
the
angle
of
maximum
torque
.
Hence
the
name
mho
unit
.
When
offset
is
used
the
transactors
(
01
,
02
and
03
)
are
energized
with
line
currents
and introduce
a
voltage
(
proportional
to
the
current
)
added
to
the
line
-
to
-
line
voltage
received
by
the
units
.
This
voltage
offsets
the
circular
characteristic
of
the
OM
units
in
the
R
-
X
diagram
.
CHARACTERISTICS
OM
UNIT
-
WITH
OFFSET
When the
offset
is
used the circular
characteristic
is
moved
along
the
X
-
axis
as
shown
in
Fig
.
4
.
OM
UNIT
-
ZERO
OFFSET
Impedance
Characteristic
The
impedance
characteristic
of
the
OM
unit
is
shown
in
Fig
.
4
for
the
three ohm
basic minimum
reach
setting
at
a
maximum
torque
angle
75
degrees
.
This
circle
can
be
expanded
by
means
of
the mho
taps
on
the
autotransformer
tap
block
providing
a
range
of
up
to
10
/
1
,
or
by
changing
the
basic
minimum
reach
of
the
unit
by
means
of
the links
on
the
rear
providing
a
total
range
of
up
to
30
/
1
.
The
circle
will
always
pass
through
the
origin
and
have
a
diameter
along
the
75
degree
impedance
line
equal
to
the
ohmic
reach
of
the
unit
as
expressed
by
the
following
:
(
100
)
Zi
^
Ohmic
Reach
=
Tap
Setting
(
%
)
6
Courtesy of NationalSwitchgear.com

GEK
-
1291
where
:
Z
.
.
.
.
.
=
basic
minimum
phase
-
to
-
neutral
ohmic
reach
of
the
unit
min
Directional
Action
The
OM
unit
is
carefully
adjusted
so
that
when
it
is
connected
for
zero
offset
it
will
have
correct
directional
action
under
steady
-
state
,
low
voltage
and
low
current
conditions
.
For
faults
in
the
non
-
tripping
direction
,
the
contacts
will
remain
open
at
zero
volts
between
zero
and
60
amperes
.
For
faults
in
the
tripping
direction
,
the
unit
will
close
its
contacts
between
the
current
limits
in
Table
III
for
the
three
basic
minimum
reach
settings
at
the
voltage
shown
:
TABLE
III
Basic
Min
Reach
Tap
*
*
Volts
(
Studs
17
-
18
)
Current
Range
for
Correct
Directional
Action
(
Amps
)
12
-
60
0.5
4.0
1.0
6
-
60
4.0
4
-
60
1.5
4.0
3
-
60
2.0
4.0
2
-
60
4.0
3.0
2
-
60
4.0
4.0
4.0
1
-
60
6.0
*
*
The
unit
is
set
at
the
factory
on
the
middle
tap
for
correct
directional
action
over
the
indicated
current
range
.
A
variation
of
+
10
percent
can
be
expected
on
the
values
listed
.
The
values
given
in
the
above
table
are
for
the
"
strong
spring
setting
"
.
For
the
"
weak
spring
setting
"
the
same
currents
limits
apply
at
2.0
volts
.
The
relay
is
shipped
with
"
strong
setting
"
.
If
the
"
weak
spring
setting
"
is
desired
refer
to
CONTROL
SPRING
ADJUSTMENTS
under
SERVICING
for
instruc
-
tions
.
For
performance
during
transient
low
-
voltage
conditions
,
where
the
voltage
was
normal
at
120
volts
prior
to
the
fault
,
refer
to
the
paragraph
below
on
memory
action
.
Underreach
At
reduced
voltage
the
ohmic
value
at
which
the
0
M
unit
will
operate
may
be
somewhat
lower
than
the
calculated
value
.
This
"
pullback
"
or
reduction
in
reach
is
shown
in
Figs
.
5
and
6
for
the
"
Strong
Spring
Setting
"
.
The
unit
reach
in
percent
of
setting
is
plotted
against
the
three
-
phase
fault
current
for
three
ohmic
reach
tap
settings
.
Note
that
the
fault
current
scale
changes
with
the
basic
minimum
reach
setting
.
The
0
M
unit
will
operate
for
all
points
to
the
right
of
the
curve
.
The
steady
-
state
curves
of
Figs
.
5
,
6
,
7
,
and
8
were
determined
by
tests
performed
with
no
voltage
supplied
to
the
relay
before
the
fault
was
applied
.
The
dynamic
curves
were
obtained
with
full
rated
voltage
of
120
volts
supplied
to
the
relay
before
the
fault
was
applied
.
Memory
Action
The
dynamic
curves
of
Figs
.
5
and
7
illustrate
the
effect
of
memory
action
in
the
0
M
unit
which
maintains
the
polarizing
flux
for
a
few
cycles
following
the
inception
of
the
fault
.
This
memory
action
is
particularly
effective
at
low
voltage
levels
where
it
enables
the
0
M
unit
to
operate
for
low
fault
currents
.
This
can
be
most
forcefully
illustrated
for
a
zero
voltage
fault
by
referring
to
Figs
.
5
and
7
.
A
zero
voltage
fault
must
be
right
at
the
relay
bus
and
therefore
,
to
protect
for
this
fault
,
it
is
imperative
that
the
relay
reach
zero
percent
of
its
setting
.
Fiqs
.
5
and
7
show
that
the
mho
unit
,
under
static
conditions
will
not
see
a
fault
at
zero
percent
of
the
relay
setting
regardless
of
the
tap
setting
.
However
,
under
dynamic
conditions
when
the
memory
action
is
effective
,
Fig
.
5
shows
that
the
mho
unit
with
a
three
ohm
basic
minimum
reach
and
100
percent
tap
setting
will
operate
if
I
is
greater
than
two
amperes
.
7
Courtesy of NationalSwitchgear.com

GEK
-
1291
The
memory
action
will
close
the
contact
for
only
a
short
period
of
time and
therefore
,
memory
action
cannot
be
relied
on
if
the
tripping
is
delayed
.
When
the
relay
is used
to
trip
the
breaker
through
the
contacts
of
a
timing relay
the
static
characteristic
should
be
used
.
For
this
application
the
relay
is
not
required
to
operate
for
nearby
faults
and
there
will
be
sufficient
voltage
to
give
tripping
without
depending
on
memory
action
.
Transient
Overreach
Under
transient
conditions
the
OM
unit
has
a
tendancy
to
close its
contact
momentarily
for
a
fault
impedance
greater
than its
impedance
setting
.
This
tendency
is
called
transient overreach and is
a
function
of
the
degree
of
asymmetry
in
the
fault
current
wave
,
and
the circuit
angle
(
the
angle
of
system
from
the
point
of
the
fault
to
the
source
of
generation
)
.
For normal
CEB
52
A
applications
,
transient
overreach
is
of
no
significance
since
the
OM
unit
does
not
perform
a
precise
measuring
function
.
Operating
Time
The
operating
time
of
the
OM
unit
is
determined
by
a
number
of
factors
such
as
the basic minimum
reach
setting
of
the unit
,
fault
current
magnitude
,
ratio
of
fault
impedance
to
relay
reach
,
and
magnitude
of
relay
voltage
prior
to
the
fault
.
The
operating
time
curves
for
the
OM
unit
are
shown
in
Figs
.
9
and
10
.
All
curves
in
these
figures
are
for
the
condition
of
rated volts
prior
to
the
fault
with
100
percent
restraint
tap
setting
.
The
curves
in
Fig
.
9
show
the
average
operating
time
of
the unit
,
that is the time
to
close
the
normally
open
contact
with
the
unit
connected
for
zero
offset
.
These
curves
also
apply
for
faults
in
the
forward
direction
if
the unit is
connected
for
0.5
ohm
offset
.
The
curves
in
Fig
.
10
show
opening
times
of
the
normally
closed
contact
,
with
the
unit
connected
for
0.5
ohm
offset
for faults
in
the
direction
of
the
offset
(
reverse
)
.
It
will
be
noted
that
for
equivalent
conditions
,
that is
for
the
same
operating
current
and
the
same
ratio
of
fault
impedance
to
reach
setting
(
or
offset
)
,
the
OM
unit
is
faster for faults
in
the
forward
direction
.
This
results
from
the
strong
initial
"
memory
action
"
inherent
in
the
unit
which
tends
to
sustain
the
polarizing
flux
for
a
few
cycles
following
inception
of
the
fault
.
For
faults
in
the
forward
direction
this
produces
a
higher
operating
torque
and
hence
faster
operation
.
TAPPED
AUTOTRANSFORMER
The
ohmic
reach
of
the
OM
units
may
be
adjusted
,
by
means
of
taps
on
the
two
autotransformers
.
Each
autotransformer
has
two
windings
.
One
winding
is
tapped
in
10
percent
steps
from
15
percent
to
95
per
-
cent
.
The
other
winding
is
tapped
at
0
percent
,
1
percent
,
3
percent
and
5
percent
.
The
desired
tap
setting
is
made
by
the
proper
location
of
the
leads
marked No
.
1
and
the
jumper
connecting
the
two
windings
of
the
autotransformer
.
Note
that
the
0
-
5
percent
winding
may
be
added
or
subtracted
from
the
15
-
95
percent
winding
.
The
tap
setting
required
to
protect
a
zone
Z
ohms
long
,
where
Z
is the
positive
phase
sequence
phase
-
to
-
neutral
impedance
expressed
in
secondary
terms
,
is
determined
by
the
following
equation
:
(
100
)
(
Min
.
Ohms
Setting
)
cos
(
0
-
0
)
Tap
Setting
=
Z
where
:
0
=
Power
factor
angle
of
fault
impedance
0
=
Angle
of
maximum
torque
of
the unit
Example
:
TAP
SETTING
DESIRED
=
91
8
Courtesy of NationalSwitchgear.com

GEK
-
1291
Set
the
other
end
to
5
percent
.
Set
one
end
of
jumper
lead
to
95
percent
.
(
Note
the
4
percent
setting
of
the
0
-
5
percent
winding
subtracts
from
the
95
percent
settings
.
Set
No
.
1
on
1
percent
.
Example
2
:
TAP
SETTING
DESIRED
=
89
Set
the
other
end
to
1
percent
.
Set
one
end
of
jumper
lead
to
85
percent
.
(
Note
the
4
percent
setting
of
the
0
-
5
percent
winding
adds
to
the
85
percent
setting
)
.
Set
No
.
1
to
5
percent
.
BURDENS
CURRENT
CIRCUITS
The
maximum
current
burden
imposed
on
each
current
transformer
at
five
amperes
is
given
in
Table
IV
.
TABLE
IV
Rated
Frequency
VA
P
.
F
.
Ohmic
Reach
R
Watts
X
2.75
0.98
2.70
0.5
-
15
0.108
0.022
60
4.08
3.83
0.153
0.056
0.94
1
-
30
60
17.3
0.88
15.2
2
-
60
0.328
0.610
60
2.55
2.50
0.020
0.98
0.100
1
-
30
50
This
data
is
for
the
maximum
basic
reach
tap
setting
.
The
burden
on
the
two
lower
basic
reach
tap
settings
will
be
lower
.
The
above
data
includes
the
burden
of
the
transactor
used
to
offset
the
mho
characteristic
.
If
the
offset
tap
is
in
zero
the
burden
will
be
slightly
less
.
POTENTIAL
CIRCUITS
The
maximum
potential
burden
imposed
on
each
potential
transformer
at
120
volts
is
listed
in
Table
V
.
TABLE
V
Rated
Frequency
VA
Watts
Circuit
R
X
P
.
F
9.2
1540
-
j
162
9.1
Polarizing
60
0.99
8.0
4.6
0.57
1025
+
jl
460
60
Restraint
8.0
0.99
7.9
1800
-
j
175
Polarizing
50
8.2
4.7
0.58
1020
+
j
1440
Restraint
50
The
potential
burden
of
the
0
M
unit
is
maximum
when
the
restraint
tap
is
set
for
100
percent
.
The
restraint
circuit
burden
and
hence
the
total
relay
burden
will
decrease
when
the
restraint
tap
setting
is
less
than
100
percent
.
The
potential
burden
at
tap
settings
less
than
100
percent
,
can
be
calculated
from
the
following
formula
.
VA
=
(
a
+
jb
)
(
Tap
TS
,
ltt
1
ng
)
2
+
(
c
*
Jd
)
100
9
Courtesy of NationalSwitchgear.com

GEK
-
1291
The
terms
(
a
+
jb
)
and
(
c
+
jd
)
represent
the
burden
of
the
mho
unit
potential
circuits
expressed
in
watts
and
vars
with
their
taps
on
100
percent
.
The
values
of
these
terms
are
given
in
Table
VI
.
TABLE
VI
a
_
ti
a
Rated
Frequency
"
b
"
"
c
"
UdM
Watts
Vars
Watts
Vars
60
4.6
+
j
6.5
9.1
~
j
1.0
50
4.7
+
j
6.6
7.9
-
j
0.8
CONSTRUCTION
The
type
CEB
52
A
relays
are
assembled
in
a
deep
large
-
size
,
double
-
end
(
L
2
D
)
drawout
case
having
studs
at
both
ends
in
the
rear
for
external
connections
.
The
electrical
connections
between
the
relay
units
and
the
case
studs
are
made
through
stationary
molded
inner
and
outer
blocks
between
which
nests
a
re
-
movable
connecting
plug
which
completes
the
circuits
.
The
outer
blocks
attached
to
the
case
have
the
studs
for
the
external
connections
,
and
the
inner
blocks
have
the
terminals
for
the
internal
connections
.
Every
circuit
in
the
drawout
case
has
an
auxiliary
brush
,
as
shown
in
Fig
.
11
,
to
provide
adequate
overlap
when
the
connecting
plug
is
withdrawn
or
inserted
.
Some
circuits
are
equipped
with
shorting
bars
(
see
internal
connections
in
Fig
.
12
)
,
and
on
those
circuits
,
it
is
especially
important
that
the
auxi
-
liary
brush
make
contact
as
indicated
in
Fig
.
11
with
adequate
pressure
to
prevent
the
opening
of
important
interlocking
circuits
.
The
relay
mechanism
is
mounted
in
a
steel
framework
called
the
cradle
and
is
a
complete
unit
with
all
leads
terminated
at
the
inner
blocks
.
This
cradle
is
held
firmly
in
the
case
with
a
latch
at
both
top
and
bottom
and
by
a
guide
pin
at
the
back
of
the
case
.
The
connecting
plug
,
besides
making
the
electrical
connections
between
the
respective
blocks
of
the
cradle
and
case
,
also
locks
the
latch
in
place
.
The
cover
,
which
is
drawn
to
the
case
by
thumbscrews
,
holds
the
connecting
plugs
in
place
.
The
target
reset
mechanism
is
a
part
of
the
cover
assembly
.
The
relay
case
is
suitable
for
either
semiflush
mounting
on
all
panels
up
to
two
inches
thick
and
appropriate
hardware
is
available
.
However
,
panel
thickness
must
be
indicated
on
the
relay
order
to
insure
that
proper
hardware
will
be
included
.
A
separate
testing
plug
can
be
inserted
in
place
on
the
panel
either
from
its
own
source
of
current
and
voltage
,
or
from
other
sources
,
or
the
relay
can
be
drawn
out
and
replaced
by
another
which
has
been
tested
in
the
laboratory
.
Fig
.
1
shows
the
relay
removed
from
its
drawout
case
with
all
major
components
identified
.
Symbols
used
to
identify
circuit
components
are
the
same
as
those
which
appear
on
the
internal
connection
diagram
in
Fig
.
12
.
The
relay
includes
three
similar
mho
sub
-
assembly
elements
mounted
on
the
front
of
the
cradle
and
a
plate
with
transformers
and
tap
blocks
mounted
on
the
back
of
the
cradle
(
see
Fig
.
1
)
.
The
mho
sub
-
assembly
includes
the
four
pole
unit
and
the
associated
circuit
components
.
Rheostats
(
R
21
,
R
22
,
R
23
)
used
in
setting
the
angle
of
maximum
torque
and
rheostats
Rll
,
R
12
,
R
13
,
used
in
setting
the
basic
minimum
reach
can
be
adjusted
from
the
front
of
the
relay
.
The
tap
blocks
for
changing
the
basic
minimum
reach
of
the
units
and
for
selecting
the
offset
are
mounted
on
the
back
.
The
relay
must
be
removed
from
its
case
to
make
the
settings
.
RECEIVING
,
HANDLING
AND
STORAGE
These
relays
,
when
not
included
as
a
part
of
a
control
panel
,
will
be
shipped
in
cartons
designed
to
protect
them
against
damage
.
Immediately
upon
receipt
of
a
relay
,
examine
it
for
any
damage
sustained
in
transit
.
If
injury
or
damage
resulting
from
rough
handling
is
evident
,
file
a
damage
claim
at
once
with
the
transportation
company
and
promptly
notify
the
nearest
General
Electric
Company
Apparatus
Sales
Office
.
10
Courtesy of NationalSwitchgear.com