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

GEK
-
1291
Reasonable
care
should
be
exercised
in
unpacking
the
relay
in
order
that
none
of
the
parts
are
injured
or
the
adjustments
disturbed
.
If
the
relays
are
not
to
be
installed
irrmediately
,
they
should
be
stored
in
their
original
cartons
in
a
place
that
is
free
from
moisture
,
dust
and
metallic
chips
.
Foreign
matter
collected
on
the
outside
of
the
case
may
find
its
way
inside
when
the
cover
is
removed
and
cause
trouble
in
the
operation
of
the
relay
.
ACCEPTANCE
TESTS
Immediately
upon
receipt
of
the
relay
,
an
INSPECTION
AND
ACCEPTANCE
TEST
should
be
made
to
insure
that
no
damage
has
been
sustained
in
shipment
and
that
the
relay
calibrations
have
not
been
disturbed
.
If
the
examination
or
test
indicates
that
readjustment
is
necessary
,
refer
to
the
section
on
SERVICING
.
VISUAL
INSPECTION
Check
the
nameplate
stamping
to
insure
that
the
model
number
and
rating
of
the
relay
agree
with
the
requisition
.
Remove
the
relay
from
its
case
and
check
that
there
are
no
broken
or
cracked
molded
parts
or
other
signs
of
physical
damage
,
and
that
all
screws
are
tight
.
MECHANICAL
INSPECTION
1
.
It
is
recommended
that
the
mechanical
adjustments
in
Table
VII
be
checked
.
2
.
There
should
be
no
noticeable
friction
in
the
rotating
structure
of
the
units
.
Make
sure
control
springs
are
not
deformed
and
spring
convolutions
do
not
touch
each
other
.
With
the
relay
well
leveled
in
its
upright
position
,
the
contacts
of
all
three
units
must
be
open
.
The
moving
contacts
of
the
units
should
rest
against
the
backstop
.
The
armature
and
contacts
of
the
seal
-
in
unit
should
move
freely
when
operated
by
hand
.
There
should
be
at
least
1
/
32
inch
wipe
on
the
seal
-
in
contacts
.
Check
the
location
of
the
contact
brushes
on
the
cradle
and
case
blocks
against
the
internal
connec
-
tion
diagram
for
the
relay
.
3
.
4
.
5
.
6
.
TABLE
VII
CHECK
POINTS
OM
UNITS
Rotating
Shaft
End
Play
0.010
-
0.015
Inch
Contact
Gap
0.040
-
0.060
Inch
Contact
Wipe
0.003
-
0.005
Inch
ELECTRICAL
CHECKS
-
0
M
UNITS
Before
any
electrical
checks
are
made
on
the
mho
units
the
relay
should
be
connected
as
shown
in
Fig
.
13
and
be
allowed
to
warm
up
for
approximately
15
minutes
with
the
potential
circuit
alone
energized
at
rated
voltage
and
the
restraint
taps
set
at
100
percent
.
The
units
were
warmed
up
prior
to
factory
ad
-
justment
and
if
rechecked
when
cold
will
tend
to
underreach
by
three
or
four
percent
.
Accurately
calibra
-
ted
meters
are
of
course
essential
.
It
is
desirable
to
check
the
factory
setting
and
calibrations
by
means
of
the
tests
described
in
the
following
sections
.
The
0
M
units
were
carefully
adjusted
at
the
factory
and
it
is
not
advisable
to
disturb
these
settings
unless
the
following
checks
indicate
conclusively
that
the
settings
have
been
disturbed
.
If
readjustments
are
necessary
refer
to
the
section
on
SERVICING
for
the
recommended
procedures
.
Test
connections
for
checking
correct
0
M
unit
operation
are
shown
in
Fig
.
13
.
11
Courtesy of NationalSwitchgear.com

GEK
-
1291
1
.
CONTROL
SPRING
ADJUSTMENT
Be
sure
that
the
relay
is
level
in
its
upright
position
.
Leave
the
relay
connected
as
shown
in
Fig
.
13
and
leave
the
restraint
taps
in
the
100
percent
position
.
Use
the
following
procedure
in
checking
each
unit
.
With
the
current
set
at
five
amperes
and
the
volt
-
age
studs
at
120
volts
,
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
the
value
shown
in
Table
Villa
for
the
unit
being
tested
,
that
is
so
current
lags
voltage
by
an
angle
equal
to
the
angle
of
maximum
torque
of
the
unit
.
Now
reduce
the
voltage
to
the
low
test
voltage
,
and
reduce
the
current
to
about
one
ampere
.
Gradually
increase
the
current
until
the
contacts
of
the
unit
just
close
.
This
should
occur
between
the
current
listed
in
Table
VIII
.
TABLE
VUI
-
a
Basic
Minimum
Reach
Phase
Angle
Meter
Reads
Set
Pickup
Current
Tap
VAB
Offset
Used
(
Volts
)(
Amps
)
Tap
0.5
-
1.5
1.0
285
Out
4.0
4.25
-
5.75
1.0
-
3.0
2.0
285
4.0
Out
2.12
-
2.88
2.0
-
6.0
4.0
285
4.0
Out
1.06
-
1.44
2
.
CLUTCH
ADJUSTMENT
The
OM
units
include
a
high
-
set
clutch
between
the
cup
and
shaft
assembly
and
the
moving
contact
to
prevent
damage
during
heavy
fault
conditions
.
These
clutches
have
been
set
at
the
factory
to
slip
at
approximately
40
-
60
grams
applied
tangentially
at
the
moving
contact
.
This
can
best
be
checked
in
the
field
in
terms
of
volt
-
amperes
by
the
following
method
.
Use
the
connections
of
Fig
.
13
and
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
the
value
in
Table
IX
for
the
unit
to
be
checked
,
at
120
volts
and
five
amperes
.
Disconnect
the
No
.
1
re
-
straint
tap
leads
from
the
tap
block
and
set
the
mho
units
for
maximum
basic
minimum
reach
and
offset
"
out
"
.
With
the
voltage
across
relay
studs
set
at
120
V
,
increase
the
current
until
the
clutch
just
slips
.
This
should
occur
between
the
values
given
below
:
TABLE
VUI
-
b
Basic
Ohmic
Range
Use
Current
to
just
Slip
Clutch
(
Amps
)
Tap
0.5
-
1.5
1.5
over
’
60
amps
1
-
3
3.0
34
“
56
2
-
6
6.0
16
.
Q
-
28
3
.
OHMIC
REACH
With
the
relay
still
connected
as
shown
in
Fig
.
13
and
the
restraint
tap
leads
in
the
100
percent
position
,
make
connections
shown
in
Table
IX
and
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
the
angle
shown
in
the
table
for
the
unit
to
be
checked
.
Now
reduce
the
voltage
to
the
value
shown
in
Table
IX
and
increase
the
current
gradually
until
the
normally
open
contacts
of
the
unit
just
close
.
This
should
occur
within
the
limits
shown
in
Table
IX
.
Note
that
the
links
on
the
tap
blocks
are
set
to
the
position
which
gives
the
basic
minimum
reach
shown
in
the
table
.
Note
that
for
the
test
conditions
,
the
OM
units
sees
a
phase
-
to
-
phase
fault
of
twice
the
basic
mini
-
mum
reach
.
The
relays
are
normally
shipped
from
the
factory
with
the
basic
minimum
reach
adjustment
taps
of
the
units
in
the
middle
setting
.
If
the
units
are
set
on
either
of
the
remaining
basic
minimum
reach
taps
,
the
basic
reach
of
the
units
will
be
within
±
5
percent
of
the
tap
plate
marking
.
NOTE
:
Basic
minimum
reach
is
equal
to
(
A
+
B
)
link
settings
.
12
Courtesy of NationalSwitchgear.com

GEK
-
1291
TABLE
IX
Pickup
Current
Phase
Angle
Meter
Reads
Set
Basic
Minimum
Reach
Offset
VAB
Tap
Used
(
Amps
)
(
Volts
)
Tap
19.2
-
20.8
Out
285
40
0.5
-
1.5
1.0
14.4
-
15.6
Out
285
60
1.0
-
3.0
2.0
7.2
-
7.8
Out
2.0
-
6.0
285
60
4.0
4
.
ANGLE
OF
MAXIMUM
TORQUE
For
checking
the
angle
of
maximum
torque
the
connections
of
Fig
.
13
will
be
used
with
the
restraint
tap
leads
set
at
100
percent
position
,
and
with
the
voltage
set
at
the
value
shown
in
Table
X
for
the
unit
to
be
checked
.
The
minimum
reach
taps
should
be
set
on
the
middle
reach
position
.
In
checking
the
mho
units
the
following
procedure
would
be
used
.
First
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
315
degrees
.
Note
that
while
the
phase
angle
is
being
set
,
the
current
should
be
at
five
amperes
and
the
voltage
shown
in
Table
X
.
Increase
the
current
slowly
until
the
mho
unit
picks
up
.
The
pickup
current
should
be
within
the
limits
shown
in
the
table
.
Now
reset
the
phase
angle
at
255
degrees
and
again
check
the
current
required
to
pick
up
the
mho
unit
.
This
current
should
fall
within
the
same
limits
as
for
the
315
degree
check
.
Note
that
the
two
angles
used
in
the
previous
check
,
i
.
e
.
315
degrees
and
255
degrees
,
are
30
degrees
away
from
the
angle
of
maximum
torque
.
An
examination
of
the
OM
unit
impedance
characteristic
in
Fig
.
4
shows
that
the
ohmic
reach
of
the
unit
should
be
the
same
at
both
315
degrees
and
255
degrees
and
should
be
0.866
times
the
reach
at
the
angle
of
maximum
torque
.
TABLE
X
Phase
Angle
Meter
Reading
Basic
Minimum
Ohmic
V
Pickup
(
amps
)
Use
Maximum
AB
Test
Angles
Offset
Set
at
(
Volts
)
Tap
Torque
Angle
Tap
21.7
-
24.5
Out
40
315
285
255
0.5
-
1.5
1.0
16.5
-
18.5
Out
2.0
285
315
255
60
1
-
3.0
8.2
-
9.2
Out
255
60
4.0
285
315
2
-
6
5
.
OFFSET
CHECK
With
the
relay
connected
as
shown
in
Fig
.
13
and
the
restraint
tap
leads
in
the
100
percent
position
,
make
settings
shown
on
Table
XI
and
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
the
angle
shown
in
the
table
for
the
unit
to
be
checked
.
Reduce
the
voltage
to
the
value
shown
and
increase
the
current
gradually
until
the
normally
open
contacts
of
the
unit
just
close
.
This
should
occur
within
the
current
limits
shown
in
Table
XI
.
TABLE
XI
VAB
Pickup
Basic
Minimum
Ohmic
Phase
Angle
Meter
Reads
Set
Use
Offset
Tap
at
(
Amps
)
(
Volts
)
Tap
18
-
22
18
-
22
18
-
22
18
-
22
10
0.25
0.5
-
1.5
1.0
-
3.0
1.0
-
3.0
2.0
-
6.0
1.0
105
8
0.20
2.0
105
20
0.50
2.0
105
20
4.0
105
0.50
13
Courtesy of NationalSwitchgear.com

GEK
-
1291
ELECTRICAL
TESTS
-
TARGET
SEAL
-
IN
UNIT
The
target
seal
-
in
unit
has
operating
coils
as
given
in
Table
II
.
The
relay
is
shipped
from
the
factory
with
the
tap
screw
in
the
maximum
ampere
position
.
The
operating
point
of
the
seal
-
in
unit
can
be
checked
by
connecting
from
DC
source
(
+
)
to
stud
11
of
the
relay
and
from
stud
1
through
an
adjustable
resistor
and
ammeter
back
to
(
-
)
.
Connect
a
jumper
from
stud
12
to
stud
1
also
so
that
the
seal
-
in
contact
will
protect
the
OM
unit
contacts
.
Then
close
the
OM
unit
contact
by
hand
and
increase
the
DC
current
until
the
seal
-
in
unit
operates
.
It
should
pick
up
at
tap
value
or
slightly
lower
.
Do
not
attempt
to
interrupt
the
DC
current
by
means
of
the
OM
contacts
.
INSTALLATION
PROCEDURE
LOCATION
The
location
of
the
relay
should
be
clean
and
dry
,
free
from
dust
excessive
heat
and
vibration
,
and
should
be
well
lighted
to
facilitate
inspection
and
testing
.
MOUNTING
The
relay
should
be
mounted
on
a
vertical
surface
,
shown
in
Fig
.
20
.
The
outline
and
panel
drilling
dimensions
are
CONNECTIONS
The
internal
connections
of
the
CEB
52
A
relay
are
shown
in
Fig
.
12
.
An
elementary
diagram
of
typical
external
connections
is
shown
in
Figs
.
17
and
18
.
VISUAL
INSPECTION
Remove
the
relay
from
its
case
and
check
that
there
are
no
broken
or
cracked
component
parts
and
that
all
screws
are
tight
.
MECHANICAL
INSPECTION
Recheck
the
six
adjustments
mentioned
under
MECHANICAL
INSPECTION
in
the
section
under
ACCEPTANCE
TESTS
.
PORTABLE
TEST
EQUIPMENT
To
eliminate
the
errors
which
may
result
from
instrument
inaccuracies
and
to
permit
testing
the
mho
units
from
a
single
-
phase
AC
test
source
,
the
test
circuit
shown
in
schematic
form
in
Fig
.
14
is
recommended
.
In
this
first
R
$
+
jK
$
is
the
source
impedance
,
SF
is
the
fault
switch
,
and
R
,
+
jX
|
_
is
the
impedance
of
the
line
section
for
which
the
relay
is
being
tested
.
The
autotransformerTA
,
which
is
across
the
fault
switch
and
line
impedance
is
tapped
in
10
percent
and
one
percent
steps
so
that
the
line
impedance
R
[
_
+
jX
|
_
may
be
made
to
appear
to
the
relay
very
nearly
as
the
actual
line
on
which
the
relay
is
to
be
used
.
This
is
necessary
since
it
is
not
feasible
to
provide
the
portable
test
reactor
Xj
_
and
the
test
resistor
with
enough
taps
so
that
the
combination
may
be
made
to
match
any
line
.
OFFSET
CHECK
With
the
relay
connected
as
shown
in
Fig
.
13
and
the
restraint
tap
leads
in
the
100
percent
position
,
make
settings
shown
on
Table
XI
and
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
the
angle
shown
in
the
table
for
the
unit
to
be
checked
.
Reduce
the
voltage
to
the
value
shown
and
increase
the
current
gradually
until
the
normally
open
contacts
of
the
unit
just
close
.
This
should
occur
within
the
current
limits
shown
in
Table
XI
.
For
convenience
in
field
testing
,
the
fault
switch
and
tapped
autotransformer
of
Fig
.
14
have
been
arranged
in
a
portable
test
box
,
Cat
.
No
.
102
-
L
201
,
which
is
particularly
adapted
for
testing
directional
and
distance
relays
.
The
box
is
provided
with
terminals
to
which
the
relay
current
and
potential
circuits
as
well
as
the
line
and
source
impedances
may
be
readily
connected
.
For
a
complete
description
of
the
test
box
the
user
is
referred
to
GEI
-
38977
.
14
Courtesy of NationalSwitchgear.com

GEK
-
1291
ELECTRICAL
TESTS
ON
THE
OM
UNITS
The
manner
in
which
reach
settings
are
made forthe
OM
units
is
briefly
discussed
in
the
CALCULATION
OF
SETTINGS
section
.
Examples
of
calculations
for
typical
settings
are
given
in
that
section
.
It
is
the
purpose
of
the
electrical
tests
in
this
section
to
check
the
ohmic
pickup
of
the
OM
units
at
the
settings
which
have
been
made
for
a
particular
line
section
.
To
check
the
calibration
of
the
OM
units
,
it
is
suggested
that
the
portable
test
box
,
Cat
.
No
.
102
-
L
201
;
portable
test
reactor
,
Cat
No
.
6054975
;
and
test
resistor
,
Cat
.
No
.
6158546
be
arranged
with
Type
XLA
test
plugs
according
to
Fig
.
15
.
These
connections
of
the
test
box
and other
equipment
are
similar
to
the
schematic
connections
shown
in
Fig
.
14
except
that
the
Type
XLA
test
plug
connections
are
now
included
.
Use
of
the
source
impedance
Re
+
kXc
,
simulating
the conditions which
would
be
encountered
in
practice
,
is
necessary
only
if
the
relay
is
to
be
tested
for
overreach
or
contact
coordination
,
tests
which
are
not
normally
considered
necessary
at
the time
of
installation
or
during
periodic
testing
.
Some
impedance
will
usually
be
necessary
in
the
source
connection
to
limit
current
in
the
fault circuit
to
a
reasonable
value
,
especially
when
a
unit
with short
reach
setting
is
to
be
checked
,
and
it
is
suggested
that
a
reactor
of
suitable
value
be used
for
this
purpose
since
this will
tend
to
limit
harmonics
in
the
fault
current
.
Since
the
reactance
of
the
test
reactor
may
be
very
accurately
determined
from
its calibration
curve
,
it
is
desirable
to
check
mho
unit
pickup
with the
fault
reactor
alone
,
due
account
being
taken
of
the
angular
difference
between the
line
reactance
,
X
[
_
,
and
mho
unit
angle
of
maximum
reach
.
The
line
reactance
XL
,
selected
should
be the
test
reactor
tap
nearest
above twice the mho unit
phase
-
to
-
neutral
reach
with
account
being
taken
of
the
difference
in
angle
of
the
test
reactor
tap
impedance
and the unit
angle
of
maximum
reach
.
From
Fig
.
16
it
is
seen
that
twice the
relay
reach
of
the
angle
of
the
test reactor
im
-
pedance
is
:
Z
Min
.
Cos
(
0
-
0
)
2
Z
Relay
=
200
Tap
Setting
%
where
:
0
=
the
angle
of
the
test
reactor
impedance
0
=
mho unit
angle
of
maximum
reach
Z
Min
=
Basic minimum
reach
of
mho units
To
illustrate
by
an
example
let
us
consider
the
percent tap
required
on
the
test
box
autotransformer
for
a
unit
that
has been
factory
adjusted
to
pick
up
at
three ohms minimum and
at
a
maximum
torque
angle
of
75
degrees
.
In
determining
the
reactor
tap
setting
to
use
,
it
may
be
assumed
that
the
angle
(
0
)
of
the
test
reactor
impedance
is
80
degrees
.
From
the
above
twice the
relay
reach
at
the
angle
of
the
test
-
reactor
impedance
is
2
Z
Relay
=
200
X
—
2
-
cos
(
80
-
75
)
=
5.98
100
Therefore
,
use
the
reactor
six
-
ohm
tap
.
Twice
the
relay
reach
at
the
angle
of
test
reactor
impedance
should
be
recalculated
using
the
actual
angle
of
the
reactor
tap
impedance
rather
than
the
assumed
80
degrees
.
Table
XII
shows the
angles
for
each
of
the
reactor
taps
.
TABLE
XII
TAP
ANGLE
COS
0
-
60
24
88
0.883
0.891
0.899
0.906
0.921
0.934
0.951
12
87
6
86
3
85
2
83
1
81
0.5
78
15
Courtesy of NationalSwitchgear.com

GEK
-
1291
From
Table
XII
it
is
seen
that
the
angle
of
the
impedance
of
the
six
-
ohm
tap
is
86
degrees
.
Therefore
:
3
cos
(
86
-
75
)
=
5.89
ohms
2
Z
relay
=
200
X
100
The
calibration
curve
for
the
portable
test
reactor
should
again
be
referred
to
in
order
to
determine
the
exact
reactance
of
the
six
-
ohm
tap
at
the
current
level
heing
used
.
For
the
purpose
of
this
illustra
-
tion
assume
that
the
reactance
is
6.1
ohms
.
Since
the
angle
of
the
impedance
of
the
six
-
ohm
tap
is
86
degrees
,
the
impedance
of
this
tap
may
be
calculated
as
follows
:
=
*
L
6.1
XL
6.115
sin
86
0.9976
From
this
calculation
it
is
seen
that
the
reactance
and
the
impedance
may
be
assumed
the
same
for
this
particular
reactor
tap
.
Actually
the
difference
need
only
be
taken
into
account
on
the
reactor
'
s
3
,
2
,
1
and
0.5
-
ohm
taps
.
The
test
box
autotransformer
tap
setting
required
to
close
the
mho
-
unit
contacts
with
the
fault
switch
closed
is
:
5.89
(
100
)
96.6
%
(
use
97
%
tap
)
%
=
6.1
Fig
.
6
should
be
checked
to
determine
that
the
test
current
used
is
high
enough
so
that
the
charac
-
teristic
is
not
off
the
calculated
value
because
of
low
current
.
If
the
ohmic
pickup
of
the
mho
unit
checks
correctly
according
to
the
above
,
the
chances
are
that
the
angle
of
the
characteristic
is
correct
.
The
angle
may
,
however
,
be
very
easily
checked
by
using
the
calibrated
test
resistor
in
combination
with
various
reactor
taps
.
The
calibrated
test
resistor
taps
are
pre
-
set
in
such
a
manner
that
when
used
with
twelve
and
six
-
ohm
taps
of
the
specified
test
reactor
,
impedances
at
60
degrees
and
30
degrees
respectively
will
be
available
for
checking
the
mho
unit
reach
at
the
60
degree
and
30
degree
position
.
The
mho
-
unit
ohmic
reach
at
the
zero
-
degree
position
may
be
checked
by
using
the
calibrated
test
resistor
alone
as
the
line
impedance
.
The
calibrated
test
resistor
is
sup
-
plied
with
a
data
sheet
which
gives
the
exact
impedance
and
angle
for
each
of
the
combinations
available
.
The
test
-
box
autotransformer
percent
tap
for
pickup
at
a
particular
angle
is
given
by
:
200
^
min
cos
(
0
-
9
)
(
100
)
%
Tap
=
Z
,
(
Tap
Setting
%
)
where
9
is
the
angle
of
maximum
torque
of
the
unit
.
0
is
the
angle
of
the
test
impedance
(
Zj
_
)
,
Z
^
is
the
60
degree
,
30
degree
or
zero
degree
impedance
value
taken
from
the
calibrated
resistor
data
sheet
.
As
in
the
case
of
the
previous
tests
,
the
load
box
which
serves
as
source
impedance
should
be
adjusted
to
allow
approximately
10
amperes
to
flow
in
the
fault
circuit
when
the
fault
switch
is
closed
.
When
checking
the
mho
unit
at
angles
of
more
than
30
degrees
off
the
maximum
reach
position
,
the
error
becomes
relatively
large
with
phase
angle
error
.
This
is
apparent
from
Fig
.
16
where
it
is
seen
for
example
,
at
the
zero
-
degree
position
that
a
two
or
three
degree
error
in
phase
angle
will
cause
a
considerable
apparent
error
in
reach
.
INSPECTION
Before
placing
a
relay
into
service
,
the
following
mechanical
adjustments
should
be
checked
,
and
faulty
conditions
corrected
according
to
instructions
in
the
ADJUSTMENTS
subsection
of
this
section
or
under
the
MAINTENANCE
section
.
The
armature
and
contacts
of
the
target
and
seal
-
in
unit
should
operate
freely
by
hand
.
There
should
be
a
screw
in
only
one
of
the
taps
on
the
right
-
hand
contact
of
the
target
and
seal
-
in
unit
.
The
target
should
reset
promptly
when
the
reset
button
at
the
bottom
of
the
cover
is
operated
,
with
the
cover
on
the
relay
.
16
Courtesy of NationalSwitchgear.com

GEK
-
1291
MHO
UNITS
There
should
be
no
noticeable
friction
in
the
rotating
structure
of
the
mho
unit
.
The
mho
unit
moving
contact
should
just
return
to
the
backstop
when
the
relay
is
de
-
energized
,
and
in
the
vertical
position
.
There
should
be
approximately
0.010
-
0.015
inch
end
play
in
the
shafts
of
the
rotating
structures
.
The
lower
jewel
screw
bearing
should
be
screwed
firmly
into
place
,
and
the
top
pivot
locked
in
place
by
its
set
screw
.
All
nuts
and
screws
should
be
tight
,
with
particular
attention
to
the
tap
plugs
.
The
felt
gasket
on
the
cover
should
be
securely
cemented
in
place
in
order
to
keep
out
dust
.
Deter
-
mine
the
impedance
and
phase
angle
seen
by
the
relays
.
Knowing
the
impedance
and
phase
angle
seen
by
the
relay
,
the
tap
value
at
which
the
relay
will
just
operate
can
be
calculated
.
It
is
then
only
necessary
to
reduce
the
tap
setting
of
the
relay
until
the
mho
units
operate
and
see
how
close
the
actual
tap
value
found
,
checks
with
the
calculated
value
.
The
calculated
value
should
taken
into
account
the
shorter
reach
of
the
mho
unit
at
low
currents
.
This
effect
is
shown
in
Fig
.
6
or
7
.
A
shorter
test
which
will
check
for
most
of
the
possible
open
circuits
in
the
AC
portion
of
the
relay
is
to
disconnect
the
current
circuits
.
All
units
should
have
strong
torque
to
the
right
when
full
voltage
is
applied
.
Replace
the
lower
plug
and
open
the
restraint
taps
.
All
units
should
operate
if
power
and
reactive
flow
are
away
from
the
station
bus
and
into
the
protected
line
section
.
If
the
direction
of
reactive
power
flow
is
into
the
station
bus
,
the
resultant
phase
angle
may
be
such
that
the
units
will
not
operate
.
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
In
view
of
the
vital
role
of
protective
relays
in
the
operation
of
a
power
system
it
is
important
that
a
periodic
test
program
be
followed
.
It
is
recognized
that
the
interval
between
periodic
checks
will
vary
depending
upon
environment
,
type
of
relay
,
and
the
user
'
s
experience
with
periodic
testing
.
Until
the
user
has
accumulated
enough
experience
to
select
the
test
interval
best
suited
to
his
individual
requirements
it
is
suggested
that
the
points
listed
under
INSTALLATION
AND
PROCEDURE
be
checked
at
an
interval
of
from
one
to
two
years
.
CONTACT
CLEANING
For
cleaning
fine
silver
contacts
,
a
flexible
burnishing
tool
should
be
used
.
This
consists
of
a
flexible
strip
of
metal
with
an
etched
-
roughened
surface
resembling
in
effect
a
superfine
file
.
The
polishing
action
is
so
delicate
that
no
scratches
are
left
,
yet
it
will
clean
off
any
corrosion
thoroughly
and
rapidly
.
Its
flexibility
insures
the
cleaning
of
the
actual
points
of
contact
.
Do
not
use
knives
,
files
,
abrasive
paper
or
cloth
of
any
kind
to
clean
relay
contacts
.
SERVICING
If
it
is
found
during
the
installation
or
periodic
tests
that
the
mho
unit
calibrations
are
out
of
limits
,
they
should
be
recalibrated
as
outlined
in
the
following
paragraphs
.
It
is
suggested
that
these
calibrations
be
made
in
the
laboratory
.
The
circuit
components
listed
below
,
which
are
normally
con
-
sidered
as
factory
adjustments
,
are
used
in
recalibrating
the
units
.
These
parts
may
be
physically
loca
-
ted
from
Fig
.
1
.
Their
locations
in
the
relay
circuit
are
shown
in
the
internal
connection
diagram
of
Fig
.
12
.
R
11
“
unlt
°
^
m
'
*
c
reach
adjustment
.
^
21
“
^
l
”
2
umt
an
9
^
e
maximum
torque
adjustment
.
R
12
“
^
2
^
unit
°
^
m
"
*
c
reach
adjustment
.
^
22
*
^
2
”
^
unit
angle
of
maximum
torque
adjustment
.
17
Courtesy of NationalSwitchgear.com

GEK
-
1291
^
13
“
^
3
”
^
un
^
°
hroic
reach
adjustment
.
R
23
*
^
T
1
un
^
t
anSHe
m
^
ximum
torque
adjustment
.
NOTE
:
Before
making
pickup
or
phase
angle
adjustments
on
the
mho
units
,
the
units
should
be
allowed
to
heat
up
for
approximately
15
minutes
energized
with
rated
voltage
alone
and
the
restraint
tap
leads
set
for
100
percent
.
Also
it
is
important
that
the
relay
be
mounted
in
an
upright
position
so
that
the
units
are
level
.
DIRECTIONAL
ADJUSTMENTS
Set
the
reach
taps
in
the
middle
reach
position
on
all
taps
.
Set
the
restraint
tap
leads
on
100
%
.
Adjust
the
control
spring
so
the
moving
contact
just
floats
in
the
center
of
its
travel
.
With
offset
at
zero
(
0
)
,
connect
the
relay
per
Figure
13
,
but
remove
the
voltage
from
leads
"
A
-
B
"
and
short
the
terminals
on
the
relay
corresponding
to
"
A
-
B
"
for
the
unit
under
test
.
Adjust
the
core
of
the
unit
under
test
so
that
the
contacts
remain
in
the
neutral
position
or
have
a
slight
opening
bias
as
the
current
is
increased
from
0
to
60
amperes
.
Unshort
the
potential
studs
.
CONTROL
SPRING
ADJUSTMENTS
Make
connections
to
the
relay
as
shown
in
Fig
.
13
and
set
the
restraint
tap
leads
on
100
percent
.
The
basic
reach
taps
should
be
set
in
the
position
for
the
basic
minimum
reach
shown
in
Table
XIII
.
Make
sure
that
the
relay
is
in
an
upright
position
so
that
the
units
are
level
.
With
the
current
set
at
five
amperes
and
the
voltage
VA
-
B
at
120
volts
,
set
phase
shifter
so
that
the
phase
angle
meter
reads
the
value
shown
in
Table
XIII
.
Now
reduce
the
voltage
to
the
test
voltage
value
and
set
the
current
at
the
value
shown
in
Table
XIII
for
the
unit
being
adjusted
.
Insert
a
blade
of
a
thin
screwdriver
into
one
of
the
slots
in
the
edge
of
the
spring
adjusting
ring
and
turn
the
ring
until
the
contacts
of
the
unit
just
close
.
If
the
contacts
were
closing
below
the
set
point
shown
in
Table
XIII
,
the
adjusting
ring
should
be
turned
to
the
right
.
If
they
were
closing
above
the
set
point
,
the
adjusting
ring
should
be
turned
to
the
left
.
OHMIC
REACH
ADJUSTMENT
The
basic
minimum
reach
of
the
OM
units
can
be
adjusted
by
means
of
the
rheostats
which
are
accessible
from
the
front
of
the
relay
.
Connect
the
relay
as
shown
in
Fig
.
13
,
leave
the
restraint
taps
at
100
percent
,
and
be
sure
that
the
basic
minimum
reach
taps
are
in
the
position
shown
in
Table
XIV
.
With
current
at
five
amperes
,
and
voltage
at
120
volts
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
the
angle
shown
in
the
table
for
the
unit
to
be
checked
.
Now
reduce
the
voltage
V
^
g
to
the
set
value
shown
in
Table
XIV
and
adjust
the
appropriate
rheostat
so
that
the
unit
picks
up
at
15
amperes
plus
or
minus
two
percent
.
ANGLE
OF
MAXIMUM
TORQUE
The
angle
of
maximum
torque
of
the
OM
units
can
be
adjusted
by
means
of
rheostats
which
are
accessible
from
the
front
of
the
relay
.
Use
the
connections
in
Fig
.
13
.
Leave
the
restraint
taps
at
100
percent
and
be
sure
that
the
basic
minimum
reach
taps
are
in
the
position
shown
in
Table
XIII
.
The
procedure
used
in
setting
angle
of
maximum
torque
is
to
adjust
the
reactor
so
that
the
pickup
amperes
,
at
a
specified
set
voltage
V
^
B
will
be
the
same
at
angles
leading
and
lagging
the
maximum
torque
angle
by
30
degrees
.
The
test
angles
,
set
voltages
,
and
the
pickup
amperes
are
shown
in
Table
XV
.
First
,
the
reach
of
the
unit
at
its
angles
of
maximum
torque
should
be
checked
and
adjusted
if
necessary
as
Next
set
the
phase
shifter
so
that
the
phase
angle
meter
reads
315
degrees
(
note
that
phase
angle
adjustments
should
be
made
at
120
volts
and
five
amperes
)
.
Then
set
V
^
B
at
60
volts
and
adjust
the
proper
reactor
so
that
the
ohm
unit
closes
its
contacts
at
17.3
amperes
plus
or
minus
two
percent
.
The
pickup
should
then
be
checked
at
255
degrees
with
the
same
set
voltage
and
should
be
17.3
amperes
plus
or
minus
two
percent
.
Refine
the
adjustments
or
rheostats
until
the
pickup
is
within
limits
at
both
255
degrees
and
315
degrees
.
Note
that
an
adjustment
of
the
angle
of
maximum
torque
will
have
a
secondary
effect
on
the
reach
of
the
unit
,
and
vice
versa
.
Therefore
,
to
insure
accurate
settings
it
is
necessary
to
recheck
the
reach
of
a
unit
whenever
its
angle
of
maximum
torque
setting
is
changed
,
and
to
continue
a
"
cross
"
adjustment
routine
of
reach
and
angle
of
maximum
torque
until
both
are
within
the
limits
specified
above
.
described
in
OHMIC
REACH
ADJUSTMENT
and
Table
XV
.
18
Courtesy of NationalSwitchgear.com

GEK
-
1291
RENEWAL
PARTS
sufficient
quantities
of
renewal
parts
be
carried
in
stock
to
enable
the
prompt
replacement
of
any
that
are
worn
,
broken
,
or
damaged
.
When
ordering
renewal
parts
,
address
the
nearest
Sales
Office
of
the
General
Electric
Company
,
specify
quantity
required
,
name
of
the
part
wanted
and
give
complete
nameplate
data
.
If
possible
,
give
the
General
Electric
Requisition
number
on
which
the
relay
was
furnished
.
It
is
recommended
that
TABLE
XIII
Basic
Minimum
Reach
Taps
Set
Value
of
Current
Phase
Angle
Meter
Reads
Set
Tap
VAB
Strong
Weak
Offset
Spring
(
Amps
)
Used
(
Volts
)
285
°
0.5
-
1.5
4.0
Out
1.0
4.25
-
5.75
2.35
-
3.20
285
°
1.0
-
3.0
4.0
Out
2.0
2.12
-
2.88
1.17
-
1.50
285
°
2.0
-
6.0
Out
4.0
4.0
1.06
-
1.44
0.60
-
0.80
TABLE
XIV
Basic
Minimum
Reach
Taps
Set
Pickup
Current
Phase
Angle
Meter
Reads
Adjustment
i
VAB
Offset
Tap
nit
Used
(
Volts
)(
Amps
)
Bottom
Top
Middle
285
°
0.5
-
1.5
1.0
Out
R
13
R
11
R
12
30
14.8
-
15.2
285
°
1.0
-
3.0
2.0
60
Out
R
13
R
11
R
12
14.8
-
15.2
11.1
-
11.4
285
°
2.0
-
6.0
4.0
Out
90
R
11
R
13
R
12
TABLE
XV
Phase
Angle
Meter
Reads
Basic
Minimum
Reach
Adjustment
Set
Pickup
Tap
Maximum
Torque
Angle
Offset
VAB
Test
Angles
Unit
Used
Tap
(
Volts
)
(
Amps
)
Middle
Bottom
Top
285
°
0.5
-
1.5
1.0
17.0
-
17.5
Out
315
R
22
R
23
255
30
R
21
285
°
1.0
-
3.0
2.0
315
255
R
22
R
23
60
R
21
Out
17.0
-
17.5
285
°
2.0
-
6.0
4.0
315
255
12.8
-
13.2
Out
R
21
R
22
R
23
90
Since
the
last
edition
,
Figure
20
has
been
revised
.
19
Courtesy of NationalSwitchgear.com

TARGET
SEAL
-
IN
UNIT
UPPER
TAP
BLOCK
RESTRAINT
TAPS
R
11
MHO
UNIT
4
>
1
-
2
R
21
MHO
UNIT
4
>
2
-
3
LOWER
TAP
BLOCK
RESTRAINT
TAPS
R
13
MHO
UNIT
<
J
>
3
-
1
R
23
FIG
.
1
A
(
8036592
)
Front
View
4
)
1
-
2
OFFSET
TAP
BLOCK
4
>
1
-
2
TAP
BLOCK
BASIC
MIN
.
REACH
4
)
2
-
3
OFFSET
TAP
BLOCK
(
J
)
2
-
3
BASIC
MIN
.
REACH
4
>
3
-
1
OFFSET
TAP
BLOCK
4
>
3
-
1
BASIC
MIN
.
REACH
FIG
.
IB
(
8036593
)
Back
View
FIG
.
1
Offset
MHO
Distance
Relay
CEB
52
A
20
Courtesy of NationalSwitchgear.com