GE CEYG51A User manual

GEK-26423D
INSTRUCTIONS
GROUND
DISTANCE
RELAY
TYPE
CEYG51A
GE
Protection
and
Control
205 Great
Valley Parkway
Maivern,
PA
19355-1337

GEK-26423
CONT
E
NTS
PAGE
iNTRODUCTION
3
APPLICATION
3
RATINGS
4
Contacts
4
OPERATINO
PRINCIPLES
5
CHARACTERISTICS
5
Pickup
6
Operating
Time
6
Burden
6
CALCULATION
OF
SETTINGS
7
CONSTRUCTION
9
RECEIVING,
HANDLING
AND
STORAGE
9
ACCEPTANCE
TESTS
10
Visual
Inspection
10
Mechanical
Inspection
10
Electrical
Tests
10
iNSTALLATION
PROCEDURE
11
Relay
Settings
11
Mechanical
Checks
11
Electrical
Checks
11
PORTABLE
TEST
EQUIPMENT 11
SERVICING
14
Restraint
Circuit
Angle
Adjustment
15
Directional
Characteristic
15
Maximum
Torque
Angle
15
Pickup
15
Clutch
Adjustment
15
RENEWAL
PARTS 16
APPENDIX
I
MINIMUM
PERMISSIBLE
REACH
SETTING
FOR
THE
CEYG51A
17
No
Zero
Sequence
Current
Compensation
17
With
Zero
Sequence
Current
Compensation
18
APPENDIX
II
MAXIMUM
PERMISSIBLE
REACH
SETTING
FOR
THE
CEYGS1A
18
No Zero
Sequence
Current
Compensation
18
APPENDIX
III
MAXIMUM
PERMISSIBLE
REACH
SETTING
FUR
THE
CEYGS1A
20
With
Zero
Sequence
Current
Compensation
20
2

GEK-26423
GROUND
DISTANCE
RELAY
CEYG51A
RELAY
INTRODUCTION
The
CEYGS1IX
is
a
three phase,
high
speed,
single zone,
mho
type, directional
distance
ground
relay.
It
consists
of
three
single-phase
units in
one
L2—D
case
with facilities
for
testing
one
unit at
a
time. One
target
and
seal-in
unit
provides
indication
of
operation
for
all
three
distance
units.
The
transient
over
reach characteristic
of
the
CEYG51A
relay
has
not
been
limited
to
the
point where
it
is
suitable
for use
as
a
first-zone
relay.
The
relay waS
specifically
designed
for
use
as
an
overreaching
device in
directional
comparison
and
transferred
tripping
schemes.
Figure
3
shows
the
internal
connections.
APPL
I
CAT
ION
The
CEYG51A
ground
mho
relay is
applied
as
the
primary
ground
relay in
directional
comparison
and
per
missive
overreaching
transferred
tripping
schemes,
employing
separate
primary
and separate
backup
protec
tion.
The
ground
rnho
units
of
the
CEYG5IA
relay
are
specifically
designed
to
detect
single
phase to
ground
faults.
To
this end
they
are
supplied
with
quadrature voltage
polarization.
Thus,
the
polarizing
voltage
will
be
quite
high
and
the
relay will have
a
high
operating
torque level
even
on
very
close
in
line to
ground
faults.
For
this
reason, these
units
are
not provided
with
memory action.
These
ground
niho
units
will
also
respond
to
three
phase
faults.
If
this
is
objectionable,
the
relay
can
be
made
unresponsive
to
any
faults not
involving
ground simply
by
adding a
non—directional zero
sequence
fault detector.
The
ground
mho
units
are
provided
with separate
current
circuits
for
zero
sequence
current
compensa
tion.
A
tapped
auxiliary
current
transformer
is
used
to
obtain
the
proper
ratio
of
compensation.
When
zero
sequence
current
compensation
is
used, the
ground
iiho
unit has
essentially
the
same
reach
on
single
phase to
ground
faults
as
on
three
phase
faults.
If
zero
sequence compensation
is
NOT
used, the
ground
niho
unit
reach
is
considerably foreshortened
on
single
phase
to
ground
faults.
See
Appendix
I
for
the
minimum
permissible
reach
settings
under
both
conditions.
In
directional
comparison
schemes,
two
CEYG51A
relays connected
back—to-back
are
required
at
each
terminal.
These
relays
operate
in
conjunction
with
a
carrier
channel to
provide
high
speed
protection
against
all
single
phase to
ground
faults
in
the
protected
line
section.
One
relay
acts to
Stop
carrier
and
trip
for
internal
faults
while
the
other
initiates
carrier
blocking
on
external
faults.
if
zero
sequence
current
compensation
is
used
on
the
carrier
stopping
and
tripping
units,
it
should
also
be
used
on
the
carrier
starting
units.
This will
facilitate
the
unit
settings
and
insure
that
both
units
that
must
coordinate
will
be
operating
on
the
same
torque
level,
in
any
event,
the
carrier
starting
unit
should
be
set as
sensitively
as
possible.
This
will
tend
to
increase
security
since
the
presence
of
a
carrier
signal
will
block
tripping.
In
permissive
overreaching
transferred
tripping
schemes,
one
CEYG51A
relay
is
required
at
each ter
minal.
It
acts
as
a
combined
transferred
trip
initiating
and
a
permissive
relay for
ground
faults in
the
protected
line
section.
The
choice
of
whether or
not to
use
sequence
current
compensation
depends
upon
the
protected
line
length
and
system
conditions.
When zero
sequence
current
compensation
is
NOT
used,
the
ground mho
unit
reach
required
may
be
about
2
to
3
times
the
positive
sequence
impedance
of the
line
in
order
to provide
the proper
coverage.
This
then
tends to
make
the
ground mho
unit
more
sensitive
to
operation
on
load
con
ditions
or
on
power
swings.
The
use
of
zero
sequence
current
compensation
reduces
the
necessary
ground
mho unit
reach
setting
to
approximately
1.25
times the
positive
sequence
impedance
of
the
line
and,
thus,
minimizes
its
response
to
load
or
power
swings.
This is
true
provided
there
is
little
or
no
mutual
im
pedance
present
from
a
parallel
line.
These
nstroctions
do
not purport
to
cover
all
details
or
variations
in
equipment
nor to
provide
For
eeerc poss:ble
contanJencj to
be
met in
connection
with
installation,
operation
or maintenance.
Should
furtn-r
information be
desired
or
should
particular
problems
arise
which are
not
covorci
sufficientlq
for
tn
purchaser’s
purposes,
the matter
should be
referred
to the General
Electric
Ccmpant.
To
he extent
,eau:red
the
products
descrrhed herein meet applicable
?.ESI, IEEE and
.S1IMA
standards;
:ot
sucn
-scranc.
s
;iven with respect
to
local codes and ordinances
because
he; varo rcatly.

GEK-26423
Whether
or
not
zero
sequence
current
compensation
is
used,
the
ground
mho
units
may
be
subject to
in
correct
operation
on
ground
faults immediately
behind
the
relay
terminals.
This will
be
dependent
upon
the
line
impedance
and
system
conditions.
It
nay
he
necessary
to
1 mit
the
mho
unit reach
setting in
order
to
avoid
this
false
tripping.
Appendix
II
gives
the
limiatations
of
the
mho
unit
reach
setting
when
zero
sequence
current compensation
is
NOT
used
Appendix
ill
gives
the
limitdtions
of
the
inho
unit
reach
setting
when
zero
sequence
current
compensation
is
used.
The
system
conch
tions
which
requ
cc
the
1
im
tdtion of
the
uho
unit
reach,
as
described
by
Appendices
II
and
Ill
,
are
rather
unusual
.
They
occur
when
the
zero
sequence
current
contribution
over
the
line
to
a
fault
behind
the
relay is
larger
than the
positive
sequence
current
contribution.
If
the
reach of
the
unfaulted
phase
units
ii
the
non-trip
direction
is
an
application
limitation,
a
zero
sequence
directional
overcurrent
relay
(CFPG16A) nay
be
used
to
supervise
the
CEYG51
operation.
This
will
permit
tripping
only
when
the
fault is
in
the
forward
direction.
The
external
connections
are
shown
in
Figure
4.
Since the
CEYG51A
is
an
extended
range
relay
with
three
basic
minimum
reach
settings,
the
best overall
performance
will
be
obtained
if
the
highest
basic
minimum
reach
tap
setting
that
will
accommodate
the
de
sired setting
is
used.
RATINGS
The
Type
CEYG5IA
relays
covered
by
these
instructions
are
available
with
potential
circuits
rated
for
operation
on
wye-wye
connected
potential
transformers
which
supply secondary
voltage
of
120
volts
phase-
to-phase.
Current
coil
ratings
and
ohmic
ranges
are
as
tabulated
below:
BASIC
MIN.
RANGE
CONTIN.
ONE
SEC.
OHMIC
REACH
OHMIC
REACH
CURRENT
RATING
CUR.
RATING
(0-N
OHMS)
(0-N
OHMS)
AMPERES
—
AMPERES
1/2/3
1
- 30
5
225
0.5/1.0/1.5
0.5
- 15
5
225
The
ohmic
reach
is
at
the
angle
of
maximum
torque of
60
degrees
lag,
and
can
be
adjusted
in
5
percent
steps
by
means
of
a
tapped
autotransformer.
It
will
be
noted
that
three
basic
minimum
reach
settings
are
listed
for
the
mho
units.
Selection
of
the
desired
basic
minimum
reach
is
made
by
means
of
links
on
terminal
boards
located
on
rear
of
the
relay.
The
positions
of
the
two
sets
of
links,
(for
each
N
unit), each
identified
as
A-B
determine
the
minimum
ohmic
reach
setting
as
follows:
MINIMUM
OHMIC
REACH
SETTING
(OHM
PHASE-TO-NEUTRAL)
A
+
B
CONTACTS
The
main
circuit-closing
contacts
of
the
re1a
will
close
and
carry
30
amperes
DC
momentarily
for
tripping
duty
at
control voltages
of
250V
DC
or
less.
The
circuit
breaker
trip
coil
should,
however,
always
by
opened
by
an
auxiliary
switch or
other
suitable
means.
If
the
tripping
current
exceeds
30
amperes,
a
tripping
relay
should
be
used.
The
current
carrying
rating
of
the
main
contacts
is
determined
by
the
tap
setting
of
the
seal—in
coil
as
shown
in
Table
I
TABLE I
TARGET AND
SEAL-IN
UNIT
2.0 0.6
0.2
——
Amp
Tap
A;np
Tap
—
Amp
Tap
I—C
Resistance
0.13
Ohms
0.6
Ohms
7
Ohms
Carry
Continuously
3.5
Amps
1.0
Amps
0.35
Amps
Carry
30
Amps
for
4
Secs.
0.5
Secs.
Carry
10
Amps
for
0.2
Secs.
4

GEK-26423
The
normally
closed contacts
between
terminals
19
and
20
will close,
carry continuously,
or
interrupt
0.3
amperes
in
non—inductive
circuits
up
to
250V
DC.
OPERATING
PRINCIPLES
The
inhu
type
units in
the
CEYGS1A
relay
are
of
the
four-pole
induction-cylinder
construction (see
Fig.
6)
with
schematic
connections
as
shown
in
Fig.
3.
The
two
side poles,
which
are
energized
by
the
phase-to-phase
voltage
in
quadrature
with
the
phase-to—neutral
voltage of
the
protected
phase,
produce
the
polarizing
flux. The
flux
in
the
front
pole,
which is
energized
by
a
percentage
of
the
phase-to-neutral
vol
tdye
of
the
protected
phase,
interacts
with
the polarizing
flux
to produce
restraint
torque.
The
flux
in
the
rear pole,
which is
energized
by
the
line
current
of
the
protected
phase,
interacts
with the
polar
izing
flux
to
produce
operating
torque.
The
torque
at
the
balance
point
for
the
phase A starting
unit
can,
therefore,
be
expressed
by
the
following
equation:
Torque =
0
=
KIaEbc
COS
((
-30)
— TEEb’
sin
B
(1)
where:
K
design
constant
=
Phase—A-to-neutral
voltage at
the
relay location
Ebc’
=
Phase
B
to
Phase C voltage
(Eb -
E)
at
the
relay
‘a
=
Phase
A
current,
at
the
relay
location
B
=
Angle
by
which
Ea
leads
Ebc’
(900
for
balanced
3-phase
condition)
T
=
Restraint
tap
setting
=
Angle
by
which
‘a
leads
Ebc
CHARACTER
1ST
1 CS
The
operating
characteristics
of
the
mho
units
in
the
CEYG51A
relay
may
be
represented
on
the
R—X
impedance
diagram as
shown
in
Fig. 7.
It
should
be
noted
that
these
steady-state
characteristics
are
for
rather
specific
fault
conditions
described
below:
The
inho
unit
has
a
circular
characteristic
which
passes
through
the
origin
of
the
R-X
diagram.
The
diameter
passing through
the
origin
defines the
angle
of
maximum
torque
of
the
unit, which
occurs
when
line
current
(Ia
for
example)
leads
the
quadrature
polarizing
voltage
(Ebc
for example)
by
30°.
Since
there
is
essentially
no
phase
shift
in
the
line—to—neutral
voltage
for a single-phase-to-ground
fault,
this
maximum
torque
angle
(i.e.
maximum
reach
angle)
occurs when
the
line current
lags
the
phase—to-neutral
voltage
by
600,
which
is
the
condition represented
in
Fig.
8.
The
diameter
of
the
impedance
circle
would nomally
be
considered
as
the
ohmic
reach
of
the
unit,
which
would
be
the
basic
minimum
reach with
the
E
tap leads
on
100
percent.
However,
if
the
niho unit
is
not
compensated
it
is
not
an
accurate
distance
measuring
until
except on
3-phase
faults,
or
for
the
special
case
of
single-phase—to-ground
faults
where the
zero-sequence
impedance
to
the
fault
is
equal to
the
positive
sequence
impedance
to
the
fault.
Instructions
are
given
in
Appendices
II
and
III
for
selecting
a
reach setting.
The
ohmic
reach of
the
mho
unit
can
be
extended
by
reducing the
percentage
of
the
fault voltage
applied
to
the
restraint
circuit,
that
is
by
setting
the
E 2
tap
leads on
a
lower
percentaoe
position
on
the
tap block.
(Zi)
100
Ohmic
ReQch
=
2
E
Tap Setting
()
(5)
5

GE
K—2
64
23
The
ohmic
reach
obtained
from
equation
(5)
assumes
that line
angle
and
maximum
torque
angle
are
equal
(600).
The
reduced
reach
at
line
angles
other
than
600
can
be
obtained
by
multiplying
the
reach
obtained
from
equation
(5)
by
cos
(60-0)
where
0
is the
line
angle.
PICKUP
The
operating
torque
will
close
the
contacts
when
the
fault
current
is
in a
certiri
direction
and
of
ufficient
magnitude to
overcome
the
restraint
torque.
The
operating
torque
on
3-phase
faults
is
a
maxi
mum
for
fault
currents
which
lag
the
unity
power
factor
position
by
60
degrees
and
is reliable
down
to
one
percent
voltage
with
currents
as
tabulated
below:
MINIMUM OHMIC
REACH
SETTING
CURRENT
RANGE FOR
RELIABLE
OPERATION
(0-N
OHMS)
0.5
36 -
60
1
18-60
1.5
12
—
60
2
9
-
60
3
6
-
60
On
single-phase-to-ground
faults
the
quadrature
polarizing potential
will
remain
quite
high
with
the
result
that
the
relay
will
operate
at
considerably
less
current
than
tabulated.
For
example,
with
a
one
percent
restraint
voltage
and
120
volts
polarizing
the
unit
will
operate
with
less
than 1
ampere
operating
current
for
the
3-ohm
minimum
reach
setting.
OPERATING
TIME
For
typical
operating
time
characteristics
see
Figure
13A
and
138.
BURDEN
The
burden
imposed
on
the
potential
transformers
by
the
type
CEYG51A
relay
with
the
restraint
tap
set
at
100
percent
is
as
given
below:
Basic
Rated
Polarizing
Circuit
Restraint Circuit
Ohms
Freq
V
Watts
Vars
VA
Volts
Watts
Vars
VA
1
-
30 60
120
10.1
8.88
13.5
70
2.7
4.0
4.8
0.5
-
15
60
120
10.1
8.88
13.5
70
0.9
1.6
1.8
1
-
30 50
120
8.41
7.38
11.2
70
1.7
3.0
3.4
I-f
the
restraint
tap
is
reduced,
the
burden
of the
restraint
circuit
is
given
by
the
following
equation:
VA
=
Watts
*(2
+
.
VARS(i”)
where
Watts
Restraint
circuit
watts
from
table
above.
VARS
=
Restraint
circuit
Vars
from
table
above.
T
Tap
in
percent.
6

GEK-26423
Basic Rated
3-4, 5-6,
or
7-8
Circuit
9-10
Circuit
Ohms
Freq.
I
X
2 1
R
X
Z
1 - 3D
60 5
0.070
0.040
0.080
5
0.210
0.120
0.240
0.5
- 15
60
5
0.007
0.005 0.008
5
0.021
0.013 0.024
1
- 30 50
5
0.058 0.033
0.067
5 0.175
0.100 0.200
NOTE: Above
data is
for
the
mho
units set
on
their
maximum ohmic
reach taps.
The
burden
for
the
lower
reach tap
settings
will be less
than the
tabulated
burdens.
CALCULATION OF
SETTINGS
In
applying
the relay
to a
particular
line and system, the
limitations
outlined
under
APPLICATION
fre
quently do not
materialize.
Therefore,
it
is
recommended that
the initial
calculations
of
1
and 2
below
be followed to
determine
what
final
calculations
may be necessary
and how
the relay
may be
applied.
1.
Determimimme
if zero
sequence
current
compensation
is required.
This
will depend
upon
on
evaluation
of
the
necessary
rnho
unit tap
settings
and the relation
of the
resulting
mho
characteristic
with
the
line
power
loadings
and power
swings. See
Appendix
I,
equations
‘b
and
I.
2.
Determine
if there
is a
limitation
in
the
application
for incorrect
operation
on
faults
behind
the
relay
terminal.
a. When
zero sequence
current
compensation
is
t.{Qi
used:
if Co is
equal
to
or less
than
C, no
further
evaluation
need be
made.
See
Appendix II,
equations
ha, hib
and
tIc.
b. When
zero
sequence current
compensation
is used: if
(3K
+
1)
Co is
equal to
or
less
than C,
no
further
evaluation
need
be made. See
Appendix
III,
equations
lIla,
hlIb
and
Ihic.
c. If
neither
a
nor b
above
is
applicable,
evaluate
the
equations
of either
Appendix
II
or
III to
determine
if it
is
necessary
to use
the zero
sequence
directional
overcurrent
supervising
re
lay,
Type
CFPH16A.
The
following
calculations
are made
as
an
example of
determining
the
actual tap
settings
to
be
used.
Consider the
protected
line to be
between
breakers
A and B on
the
portion of a
system
shown
in Fig.
5.
Assume the
following
characteristics:
Z 1 = 24.0
/790
primary
ohms
= 72.0
/750
primary
ohms
14.4
/75°
primary
ohms
CT Ratio
600/5
PT
Ratio
1200/1
Secondary
Ohms
= CT Ratio
x
Primary
Ohms
PT
Ratio
21
= 2.4
/79°
= 0.47
+ j2.36 secondary
ohms
Z 0 ’ = 7.2
/75°
= 1.9
+
j6.95
secondary
ohms
Zom
1.4
/75°
=
0.36 + jI.35
secondary ohms
Checking
Appendix
I
first
to
establish
the maximum
tap
setting
that would
still
permit
the
CEYG5IA
at
breaker
A to
detect
a
single
phase to
ground fault
(F2)
at the remote
bus,
Equation
lb
should
be
used.
The
burdens imposed
on
the
current
transformers
by
the current
circuits are
given below:
7

GEK-26423
Assume
for
this
fault
at
F2
that
a
system
study
yields
the
following
quantities.
C 0
=
0.17
C
=
0.20
=
13.7
secondary
amperes
based
on
600/5
CTs
=
4.1
secondary
amperes
10’
=
-0.88
secondary
amperes
based
on
the
protected
line
CT ratio
of 600/5.
Note
the
negative
sign
because
I
flows
in
the
opposite
direction
in
the
parallel
line
(0
to
C)
from
that
in which
I
flows
in
the
protected
line
(A to
B).
9
=
790
Substituting
these
values
and
the
values
of impedance
assumed
above
into
equation
Tb
of
Appendix
I,
we
obtain:
K
Cos
(60-79)
F
(7.2
-2.4)(0.17)
(1.4)(-0.88)
+
(0.4
÷
0.17)
+
13.7
T =
0.204K
The
value
of T
could
be
obtained
for
all
three
basic
minimum
reach
settings.
However,
the
highest
one
should
be used.
For
the
three
ohm
basic
reach
settings
K
300.
Thus,
for
this
basic
tap
setting
the
restraint
tap
T should
be
no
larger
than:
T =
0.204K
=
61
percent
Consider
now
a
ground
fault
at
Fl
immediately
behind
the
relay.
Appendix H
indicates
the approach
to
calculate
the
maximum
safe
reach
setting
to eliminate
the
possibility
of
an
incorrect
operation
on
single
or
double
phase
to
ground
faults
at this
location.
Assume
that
a
system
study
yields
the
following
system
constants:
C
0.27
C 0
=
0.11
Z 1
=
0.875
secondary
ohms
=
1.05
/780
secondary
ohms
=
1.2
Using
the
3
ohm
basic
minimum
tap
settings
established
above
and
evaluating
equations
ha,
JIb
and
TIc
of
Appendix
II,
the
minimum
permissible
values
of
tap
setting
T
are
tabulated
below.
QUANTITY
VALUE
ZI
0.875
/82°
Z 0
1.05
/780
Z 0 /Z 1
1.2
Co
0.11
C
0.27
K
100
A
123°
8
82°
T
(Equation
ha)
-10.5 Percent
T
(Equation
JIb)
-18
Percent
T
(Equation
lIc)
-14.5
Percent
8

GEK-26423
Since
all
the
values
of
T
in
the
above table
are
negative,
these
equations
impose no
restrictions
on
the
tap
setting
for
this application.
Thus, the
relays
may
be
set
in
the
range of
10
to
61
percent.
Since the
61
percent
setting
will
insure that
the
relay
will reach
only
to the
remote
bus,
a lower
setting
should
be
used.
It
is
desirable
to
set
the
relay
to
reach
at
least
25
to
50
percent
beyond the
remote
terminal.
Thus,
for
50
percent additional
reach
the
restraint
tap
setting should
be:
61
T
=
41
percent
Set
tap
on
40
percent
These
same
calculations
should be
repeated
for
the
relays at
the
remote
end
of
the
line
at
terminal
B.
If
the
application
is
for
directional
comparison
carrier,
it
will
also
be
necessary
to
determine
the
set
tings
of the
carrier starting
CEYG51A
relays at
both
terminals.
The
carrier
start
relay
settings
should
be at
least
1.25
times
the
setting
of
the
tripping
relay at
the
remote
terminal.
This will
insure
that
the
carrier
starting
relay
at
the
rear
terminal
will
outreach
the
carrier
tripping
relay at
the
remote
terminal
and
they
will,
therefore,
coordinate
properly.
In
any
event
the
carrier
starting
units
should
be
set
as
sensitively
as
possible.
In
any
case,
ALWAYS
set
the
relays
that
must
coordinate
with
each
other
on
the
same
basic
minimum
tap
setting.
Thus,
the
carrier
start
CEYG51A relay
at
terminal B
should
be
set
with
the
same
basic
minimum
reach setting
as
the
tripping
CEYG51A
relay
at
terminal
A.
If zero
sequence
current
compensation
is
used, equation
Ic
should
be
used
instead
of
equation
lb.
Thus,
we
obtain.
6.95
- 2.36
4.59
K
=
= =
0.65
per
unit
3(2.36)
7.08
T
= 0.33K
=
0.33
x
300
=
99
percent
For
the
ground
fault F2
immediately
behind
the
relay,
use
the
equation
of
Appendix
III
to
calculate
the
maximum
safe
reach
setting
when
using
zero
sequence
current
compensation.
CONSTRUCTION
The Type
CEYG51A
relay
consists
of
three
inho—type,
4—pole
induction
cylinder
units.
Each
unit
has
an
associated
tapped
autotransformer
for
controlling
reach
and
adjustable
resistors
in
the
polarizing
and
restraint
circuits
for
adjustment
of
angle
and
basic minimum
ohmic
reach.
Figures
1
and
2
show
construc
tion
details
of
the
relay.
Internal
connections
of
the
relay
are
shown
in
Figure
3.
The
components
are
mounted
on
a
cradle
assembly
which can
be
easily
removed
from
the
relay
case.
The
cradle is
locked
in
the
case
by
means
of
latches
at
the
top
and
bottom.
The
electrical
connections
between
the
case
block
and
cradle
block
are
completed
through
a removable
connection
plug.
A
separate
testing
plug
can
be
inserted
in
place of
the
connection
plig
to
permit
testing
the
relay in
its
case.
The
cover
attaches
to
the case
from
the
front and
includes
the
target
reset
mechanism
and
an
interlock
arm
to
pre
vent
the
cover
from
being
replaced
until
the
connection
plug
has
been
inserted.
Outline
and
panel
drilling
dimensions
are
shown
in
Figure 15.
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
ststained
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
Apparatus
Sales
Office.
Reasonable
care
should
be exercised
in
unpacking the
relay.
If
the
relays
are
not
to
be
installed
immediately,
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.
9

GEK-26423
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.
ViSUAL
INSPECTION
Check
the
nameplate
stamping
to
insure
that
the
model
number,
rating,
and
ohmic
range
of
the
relay
received
agree
with
the
requisition.
Remove
the
relay
from
its
case
and
check
by
visual
inspection
that
there
are
no
broken
or
cracked
molded
parts
or
other
signs
of
physical
damage,
and
that
all
screws
are
tight.
MECHANICAL
INSPECTION
It
is
recommended
that
the
following
mechanical
adjustments
be
checked:
1.
There
should
be
no
noticeable
friction
in
the
rotating
structure
of
each
unit.
The
normally
closed
contacts
should
be
closed
when
the
relay
is
in
the
upright
position.
2.
There
should
be
an
end
play
of
from
.005
to
.015
inches
on
the
shafts
of
the
rotating
structures.
The
lower jewel
screw
bearing
of
each
unit
should
be
screwed
firmly
in
place,
and
the
pivot
at
the
top
of
the
shaft
locked
by
its
set
screw.
3.
The
contact
gap
on
each
unit
should
be
approximately
.045
to
.065
inches.
There
should
be
.004
to
.012
inch
clearance
between
the
stationary
contact
rod
and
the
solid
backstop
when
the
contact is
open.
4.
The
spring
windup
should
be
sufficient
to
cause the
normally
closed
stationary
contact
to
deflect
so
that
it
just
touches
the
solid
stop
when
the
unit
is
dc—energized.
5.
The
clutch
of
each
unit
should
slip
when
a
force
of
45 to
65
grams
is
applied
to
the
moving
con
tact
assembly
at
the
moving
contact.
6.
The
armature
and
contacts
of
the
target
and
seal-in
unit
should
move
freely
when
operated
by
hand.
There
should
be
a
screw
in
only
one
of
the tap
positions
on
the
right
stationary
contact
strip.
Operate
the
armature
by
hand and
check
that
the
target
latches
in
its
exposed
position
before
the
contacts
close.
There
should
be
at
least
1/32
wipe
on
the
seal—in
contacts.
With
the
cover
fastened
securely
in
place,
check
that
the
target
resets positively
when
the
reset
button
at
the
5ottom
of
the
cover
is
operated.
7.
Check
the
location
of
the
contact
brushes
on
the
cradle
and
case blocks
against
the
internal
connection
diagram
for
the
relay.
Be
sure
that
the
shorting
bars
are
in
the
proper
locations
on
the
case
blocks,
and
that
the
long
and
short
brushes
on
the
cradle
block
agree
with
the
internal
connection
dia
gram.
Figure
11
shows
a
sectional
view
of
the
case
and
cradle
blocks with
the
connection
plug
in
place.
Note
that
there
is
an
auxiliary
brush
in each
position
on
the
case
block.
This
brush
should
be
formed
high
enough so
that
when
the
connecting
plug
is
inserted
it
engages
the
auxiliary
brush
before
striking
the
main
brush.
This
is
especially
important
in
current
and
other
circuits
with
shorting
bars
since
an
improper
adjustment
of
the
auxiliary
brush
could
result
in
a
CT
secondary
circuit
being momentarily
open
circuited.
ELECTRICAL
TESTS
It
is
recommended
that
the
following
electrical
checks
be
made
immediately
upon
receipt
of
the
relay.
1.
Polarity
Check
-
The
following
check
will
insure
that
the
relative
polarity
of
operating,
polarizing
and
restraint
circuits
of
each
unit
is
correct,
Each
unit
can
be
checked
individually
using
the
test
connections
in
Figure
9. With
all
tap leads
removed
the connections
shown
for
each
unit
should
CaUSe
the
contacts
of
that
unit
to
close.
With
the
E 2
tap
of
each
unit
set
in
the
80
percent
position,
that
unit
should
develop
a
strong
contact
opening
torque.
2.
Directional
Check
-
The
following
checks
are
to
determine
that
each
unit
has
correct
directional
characteristics.
Use
the
test
connections
shown
in
Figure
10.
Set the
voltages
to
two
volts
and
set
the
phase
shifter
so
that
the
current
leads
the voltage
by
30
degrees
with
the
connections
shown.
The
contacts
of
each
unit
should
close
at
some
value
less
than
the
minimum
amperes
given
in
Tble
III
and
remain
closed
as
the
current
is
increased
to
the
maximum
value
given
in
Table
III.
The
EL
taps
should
be
on 100
percent
for
these
tests.
10

GE
K-
26423
TABLE
III
OHMIC
REACH
MINIMUM
MAXIMUM
TAP
SETTING
AMPERES AMPERES
0.5
32
60
1.0
16
60
1.5
12
60
2.0
8
60
3.0
6
60
Set
the
phase
shifter
so
that
the
current leads the
voltage
by
210
degrees.
The
contacts
of
each
unit
should
remain open
from
zero
to
60
amperes.
3.
Maximum Torque
Angle
-
The
maximum
torque angle
of
the
mho—type
units
can
be
checked using
the
connections
shown
in
Figure 10,
but with
the
E
tap
disconnected.
The
operating
current
should be
set
for
5
amperes, with
polarizing
voltage
at
120
volts.
With
the
phase
shifter
set
so
that
operating
current leads
polarizing
voltage by
30°,
the
left
contact
of
the
unit
will be
closed.
Next
find
the
angles
on
either side
of
the
300
position
which
cause the
left
contact
to
just
open.
These
are
the
zero
torque angles
of
the
unit.
The maximum
torque
position will
be
at
the
bisector
of
the
angle
between
the
two
zero
torque
lines.
For
example,
assume
that
for
a
particular
unit
the
left
contact
just
opens
at
1100
and
3100.
The
angle
of
maximum torque
will
be:
(110
+
310)
=
210°,
ie
3Q0
lead
The
maximum
torque
angle
of
the
units
should
be
at
300
lead,
+3°.
This
is
the
angle
by
which the
operating
current
leads
the
polarizing
voltage for
a
particular
unit.
4.
Pickup Check
- The
following
check
is
to
determine
that
the
ohmic
reach
of
each
unit
is
witin
+14
percent
of
the
minimum
reach
as
given
on
the nameplate.
These
checks should
be
made
with
the
E
taps
set
at
100
percent
and
the
voltage
adjusted
for
the
value
shown
in
Table
IV
for
the
specific
ohmic
range
and
with
the
relay
connected
as
shown in
Figure 10.
Set
the
phase
shifter
so
that
current
leads
voltage by
30
degrees,
check
that
the
current
required
to
close
the
contacts
falls
within
the
range
shown
in
Table IV.
Resistor
R 11 -R 12 -R 13
should
not
be
used
to
adjust
pickup. The
resistors
are
used
to
make
the
phase angle of the
restraint circuit
the
same
as
the
phase
angle
of
the
polarizing
circuit.
TABLE IV
REACH
RESTRAINT
POLAR.
PHASE
UNIT
LINK
APPLIED APPLIED
PICKUP
ANGLE
-N
SETTING
VOLTAGE VOLTAGE
CURRENT
°LEAD
0.5
0.5
20V
120V
34.4
—
45.6
30°
1.0
1.0
25
120
21.6
- 28.5
30°
1.5
1.5
35
120
20.0
- 26.6
300
2.0
2.0
35
120
15.0 - 20.0
30°
3.0
3.0
70
120
20.0
-
26.6
30°
5.
Compensating
Winding
Check
- The
following
check
is
to
confirm
that
the
relative
polarity
of
the
compensating windings
between
terminals
9-10, is
correct.
Use
the
basic
test
connections
of
Figure
10,
but
connect the
current
circuits
as
tabulated
in
the
following:
•
I
TO
2
TO
JUMPER
UNiT
SUD
STUD
STUDS
Ml
3
10
4-9
M2
5
10
6
- 9
M3
7
10
8-9
With
voltage,
E 2
tap,
and
phase
angle
set
as
in
the
pickup
check
(4),
measure
the
current
required
to
close
the
left
contact of
edch
unit.
The
current
should
be
one
half
the
values
listed
in
Table
IV.
11

GEK-26423
6.
Target
Seal-in
Unit
—
With
the
target
in
the
down’
or
unexposed
position,
check
pickup
on
both
taps.
Use
a
DC
source
with
the
circuit
arranged
so
that
test
current
through
studs
1-11, with
Ml
contact
held
closed,
can
be
gradually
increased
to
the
pickup
point.
Pickup
current
should
be tap
rating
or
less.
Refer
to
the
section
on
Target
Seal-in
Unit
Settings
under
INSTALLATION
PROCEDURE
for
the
recommended
steps
to change
the
tap
setting.
INSTALLATION
PROCEDURE
If
after
the
ACCEPTANCE
TESTS
the
relay
is held
in storage
before
shipment
to
the
job
site,
it is
recommended
that
the
visual
and
mechanical
inspection
described
under
the
section
on
ACCEPTANCE
TESTS
be
repeated
before
installation.
The
relay
should
be
mounted
on
a
vertical
surface
in a
location
which
is
clean
and
dry
and
free
from
excessive
vibration.
The
outline
and
panel
drilling
dimensions
are
shown
in
Fig.
15.
The
internal
connections
are
shown
in
Fig.
3
and
typical
external
connections are
shown
in
Fig.
4.
RELAY
SETTINGS
1.
Mho
Units
Refer
to
the
section
on
CALCULATIONS
AND
SETTINGS
for
a discussion
of suggested
procedures
for
determining
the
mho
unit
tap
block
settings
for
a
specific
application.
The
reach
of the
mho
units
can
be
adjusted
in
five
percent steps
by
connecting
the
tap
leads
to
the
proper
taps
on
the tap
blocks.
The
red
leads
should
be
connected
to
one
of
the
10
percent
tap
positions
of
the blocks.
The
green
leads
should
be
connected
to
one
of
the
two
5t
tap
positions.
MECHANICAL
CHECKS
1.
Check
the
movable
contact
structures
of
each
unit
by
hand.
There
should
be
no
noticeable
friction.
When
the
left
contact
is
closed
by
hand
and
then
released
the
movable
structure
should
reset
to
the
right
and
reclose
the
normally
closed
contact
with
the
relay
completely
deenergized.
2.
Examine
the
contact
surfaces
for
signs
of tarnishing
or
corrosion.
Fine
silver
contacts
should
be
cleaned
with
a
burnishing
tool,
which
consists
of
a
flexible
strip
of
metal
with
an
etched,
roughened
surface.
Burnishing
tools
designed
specially
for
cleaning
relay
contacts
can
be
obtained
from
the
factory.
Do
not
use
knives,
files,
or
abrasive
paper or
cloth
of
any
kind
to
clean
relay
contacts.
3.
Operate
the
target seal-in
unit
by hand
and
check
that
the
target
latches
before
the
contacts
make,
and
that
the
contacts
have
at
least
1/32”
wipe.
With
the
cover
replaced
check
that
the
target
resets
when
the
reset
button
is
operated.
ELECTRICAL
CHECKS
Using
the
test
connections
shown
in
Figure
10
check
the
relay
reach
setting
as
described
under
ACCEPTANCE
TEST
-
PICKUP
CHECK.
PORTABLE
TEST
EQUIPMENT
The
manner
in
which
reach
settings
are
made
on
the
starting
units
is
briefly
discussed
in
the
section
titled
SAMPLE
CALCULATIONS
FOR
SETTINGS.
Examples
of
the
calculation
of
typical
settings
are
given in
that
section.
It
is the
purpose
of the
electrical tests
in
this
section
to
check
the
starting
unit
ohmic
pick
up
settings
which
have
been
made
for
a
particular
line section.
To
eliminate
errors
which
may
result
from
instrument
inaccuracies
the
test circuit
shown
in
schematic
form
in
Fig.
16
for
the
mho
units
are
recommended.
In
the
figure
R 5
+jX 5
(when
used)
is
the
source
impedance,
5 F
is the
fault
switch,
and
RL
+
jX
is
the
impedance
of
the
line
section
for
which
the
relay
is
being
tested.
The
autotransformer
TA
which
is
across
the
fault
switch
and
line
impedance
is
tapped
in
10
percent
and
1
percent steps
so
that
the
line
impedance
RL
+
jXL
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
fea
sible
to
provide
the
portable
test
reactor
XL
and
the
test resistor
with
enough
taps
so
that
the
combina
tion
may
be
made
to
match
any
line.
12

GEK-26423
For
convenience
in field
testing,
the
fault
switch
and
tapped
autotransforiner
of
Fig.
16
have been
arranged
in
a portable
test box,
Cat.
No.
102L201,
which
is
particularly
adapted
for
testing directicnal
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.
B. T[STING
TIlE MHO
UNITS
To
check the
calibration
of
the who
unit
it is
suggested
that
the test
box,
test
reactor,
and
test
resistor
be
arranged
with
Type
XLA
test plugs
as
shown
in
Fig.
18. These
connections
are
similar
to the
schematic
connections
of Fig.
16, except
that
the
XLA
test
plug
connections
are
now
included.
As
noted
in
the
section
on
CHARACTERISTICS
the
mho
unit
provides
an
accurate
distance
measurement
on
ground
faults
only
for
the special
case
where
the zero
sequence
impedance
is
equal
to the
positive
sequence
impedance
to
the
fault.
The
tests
outlined
below
check
the
line-to—neutral
ohms
that
the
unit
would
measure
under
these
conditions.
After
the who
unit
has
been
set
for
the
desired
reach,
select
a
value
of test
impedance
at
600,
that
is
RL + jXL
/60°,
which
exceeds
the reach
setting
of the
unit
by the
smallest
amount
possible.
Then
using the
test
circuit
of
Fig.
18 (note
that
current limiting
impedance
X 5
and
R 5
is omitted),
turn
the
test
box fault
switch
SF
to
the
‘ON”
position
and
adjust
the
selector
switches
to
obtain
a balance
point.
The
percent
tap setting
of
the
test box
autotransfornier,
which should
cause
the
starting
unit
to
just
close
its
contacts,
is
given
by
equation (12).
Z
cos (60
-
0)
%
Tap
=
(100)
(12)
L
where:
ZMU
=
Ohmic
reach
of
the
mho unit
(See
Equation
5
in CHARACTERISTICS
section).
ZL
=
Test
impedance
in
ohms
0
= Angle
of
test
impedance
The
portable
test
reactor
(Cat. No.
6054975)
and
test resistor
(Cat.
No.
6158546)
are normally
sold
as
a set
identified
by
a calibration
curve number
shown
on
the nameplate.
The test
resistor
taps
have
been
set at
the factory
n
conjunction
with
taps
on
the associated
test
reactor
to provide
a
range
of
impedances
at
600 and
30
angles.
If one
of
the 60°
impedance
values
thus
obtained
is
used
the
angle
9
in
the above
equation
will
be
600.
If a
resistor-reactor
tap
combination
other
than those
covered
by
the
calibration
sheet
is used,
or
if
the
test reactor
is
used
with
some other
non-inductive
resistance
to approximate
the
600
impedance, then
the
actual
value
of
0
should
be
used
in
equation
12.
The angles
of
the test
reactor
at
the various
nominal
tap
settings
are given
in Table
VI.
TABLE
VI
TEST
REACTOR
TAP
ANGLE
24
88°
12
87°
6
86°
3
85°
2
83°
1
81°
0.5
78°
As
an
illustration
of
the
above
assume
that
the
3
ohm basic
minimum
reach
link
setting
is
to
be
used
and that
is has
been
decided
to
set
the
E tap
on 45
percent.
This
setting
falls
within
the
limits
of
10
and 67
percent
determined
in the
example
in the
section
SAMPLE
CALCULATIONS OF SETTINGS.
Ohmic
reach
of
the
starting
unit
at
its
600
angle
of maximum
torque
will
then
be
6.68
ohms, as
determined
from
equation
5 in
the
CHARACTERISTICS
section.
Using
a
typical
combination
of
test
reactor
and test
resistor,
the
600
impedance
closest
above
this
reach
setting
is 14.4
ohms.
The
percent
tap
of
the
test
box
autotransfornier
at
which
the
who
unit contacts
will
just close
can
then
be calculated
as
follows
from
equation
(12):
Tap
6.68 c0 0
- 600)
(100)
= 46.3
13

GEK-
26423
The
ruho
unit
should
therefore
theoretically
close
its
contacts
at
46
percent
and
remain
open
at
47
percent.
A
range
of
40
to
54 percent
in the
balance
point
(+14
of
the
nominal)
is
satisfactory
tolerance
for
the
mho
unit.
If
the
ohmic
reach
of
the
rnho
unit
checks
correctly
according to
the
above
procedure,
the
angle
of
maximum
torque
is
probably
correct
also.
The
angle
can
be
verified
if
desired
by
checking
two
other
points
on
the
iiiho
chara 8 teristic
of
the
niho
unit.
It
is
suggested
that
the
check
be
made
for
a
fault
impedance
angle
near
90 by
using
the
test
reactor
alone,
and
for
a
fault
impedance
of
3Q0
by
using
the
appropriate
resistor-reactor
combination.
Assume
that
the
nominal
12
ohm
reactor
tap
is
used
with
RL
=
0,
and
that
the
actual
reactance
value
of
this
tap
is
11.9
ohms.
Since
the
angle
of
this tap
(Table
VI)
is
87°, the
impedance
is:
X 1
11.9
=
cos
30
993
=
11.95
ohms
It
is obvious
from
the
above
that
the
reactance
and
impedance
can
be
assumed
to
be
the
same
for
this
reactor
tap. Actually
the
difference
need
only
be
taken
into
account
on
the
3, 2,
1
and
0.5
ohm
taps.
The
test
box
autotransforrner
tap
required
for
the
contacts
to
just
close
can
be
determined
from
equation
(12)
as
follows:
6.68
cos
(60
-
87)
%
Tap
=
(100)
=
50%
11.9
A range
of
43
to
57
percent
in
the
balance
point
indicates
acceptable
tolerance
for
the
mho
unit
angle.
A
similar
approach
can
then
be
taken
using
a
3Q0
combination
of
reactor-resistor
taps.
If
a
four-wire
test
source
is
not
available,
the
mho
unit
characteristic
can
then
be
checked
using
a
three-phase, three-wire
test
source
and
the test circuit
of
Fig.
17.
Following
the
same
procedure
outlined
above
for
the
four-wire
test
circuit
the
only
difference
in
results
if
a
30°
shif
in
the
mho
characteristic.
With
these
connections
maximum
reach
occurs
at
9Q0
with
88.6w
reach
at
60
,
and
50%
reach
at
3Q0
A
mho
unit
which
produces
the
mho
characteristic
shown
in
Fig.
17
for
the
three-wire
connections
will
produce
the
mho
characteristic
shown
in
Fig.
18
when
supplied
with
normal
polarizing,
restraining,
and
operating
quantities.
TABLE
VII
UNIT
A
BC
D
E
F
TOP
15
18
16
17
3
4
MID.
16 18
17
15
56
BOT.
17
18
15
16
7
8
J
COMPENSATING
WDG
H
L
10
9
10
1.9
10
Check
the
unit
using
E
and
F
currents
as
shown
in
Table
VII
above.
Then
move
the
E
and
F
leads
to
G
and
H
connections
to
check
the
compensating
windings.
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
located
from
Figure
1
and 2.
-
Ml
unit
restraint
angle
adjustment
-
Ml
unit
angle
of
maximum
torque
adjustment
-
M2
unit
restraint
angle
adjustment
14

GEK-26423
R 22
-
M2
unit
angle
of
maximum
torque
adjustment
R 13
- M3
unit
restraint
angle
adjustment
R 23
- M3 unit
angle
of maximum
torque
adjustment
NOTE:
Before
making
pickup
or
phase
angle
adjustments on
the
mho
units,
the
unit
should
be allowed
to
heat
up
for
approximately
15 minutes
energized
with
rated voltage. Also
it
is
important
that
the
relay
be
mounted in
upright
position
so
that
the
units
are
level.
RESTRAiNT
CIRCUIT
ANGLE
ADJUSTMENT
The
resistors
R 11 -R 1 -R 13 are
used
to
make
the
phase
angle
of
the
restraint circuit
the
same
as the
phase
angle of the
polarizing
circuit.
This
is done
to
improve
the
transient performance of the
unit.
To
properly
adjust
R 11 -R 12 -R 13
the
following
is
required.
1,
Remove
lower
connection
plug.
2.
Adjust
control
spring
so
that
the
contacts
float
between
the
two
stationary
contacts,
when
the
relay
is de-energized.
3.
Connect
studs
15
and
16 to
one side
of
a
70
volt
test
source.
Connect
studs
17
and
18
to
the
other
side
of
the
70 volt
test
source.
Adjust
R 11 until
the
moving
contact
on
the top
unit
floats
be
tween
the two
stationary
contacts.
4.
Connect
studs
16
and
17 to
one
side
of
the
70
volt
test
source
and
studs
15
and
18 to
the
other
side.
Adjust
R 12
until
the
moving
contact
of the
middle
unit
floats
between
the
two
stationary
contacts.
5.
Connect
stud
15
and
17 to
one
side
of
the
70
volt
test
source
and
studs
16
and
18
to
the
other
side.
Adjust
R 13 until
the
moving
contact
of the
bottom
unit
floats
between
the two
stationary
contacts.
DIRECTIONAL CHARACTERISTIC
If
the
mho unit
fails
to
perform
properly
at
high current levels
as
outline
under
ACCEPTANCE
TESTS
the inner
stator
or core
must
be
readjusted.
This
can
be accomplished
by
means
of
rotating
the
core
(slightly
clockwise
or
counterclockwise
as
required
to
make
sure
that
the
contacts
close
and remain
closed
within
specified
currents),
with
the
special
core
adjusting
wrench.
(Cat.
No.
0178A9455
Pt.
1)
(See
Fig.
12).
MAXIMUM
TORQUE
ANGLE
The
maximum
torque angle of the
mho—type
units
can be
checked
using
connections
shown
in Fig.
10, but
with
the
E 2
taps
disconnected,
as
outlined
in
ACCEPTANCE
TESTS.
If
it
is
found
that
the
angle
of
maximum
torque
is outside
of
limits
it can be
restored
by
means
of
the
adjustable
resistors,
R 21 ,
R 22 .
and
R 23
for
mho
units
Ml,
M2
and M3
respectively.
PICKUP
The
pickup
or ohmic
reach
of each
unit
should
be
within
+14
percent
of
the
published
minimum
reach
at
the
angle
of
maximum
torque
as
checked,
in
ACCEPTANCE
TESTS.
On
the CEYG51A
the
adjustable resistors
in
the
restraint
circuits
(Ru,
Rl2,
and
R13)
are
used
to adjust
the
angle
of the
restraint
circuit
to
equal
the angle
of the
polarizing
circuit.
This
is
done
so
that the
restraint
torque
will
be
proportional
to the
area
of
the voltage
triangle.
Therefore, since
the
resistors
R 11 ,
R 12
and
R 13
are
used
to set
the
angle
of
the
restraint
circuit,
they
must
not
be used
to
adjust
reach.
CLUTCH
ADJUSTMEN1
The
clutch
of
each
unit
should
slip
when
a force
of
45-65
grams
is
applied
to
the
moving
contact.
The
cup
assembly
must be
held
securely
with
a
special
wrench
0246A7916
(1/2
inch wrench,
1/32
inch
thick)
placed
between
the
front
coils
and
the
contact
head.
The
clutch
pressure
is
varied
by
loosening
or
tightening
the
self
locking
nut
(3/8
inch)
at
the
top
of
the
cup
shaft.
15

GEK-26423
RENEWAL
PARTS
It
is
recommended
that
sufficient
quantities
of
renewal
parts
be
carried
in
stock
to
enable
the
prompt
replacerrient
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,
arid
give
the
General
Electric
Requisition
number
on
which
the
relay
was
furnished.
16

GEK-26423
APPENDIX
I
MINIMUM
PERMISSIBLE
REACH
SETTING
FOR THE
CEYG51A
The CEYG5IA
relay
will
measure
positive
sequence
impedance
and, therefore,
distance
on the
transmis
sion
line
accurately
on
three
phase
faults.
However,
on
single
phase to
ground
faults,
when zero
sequence
current
compensation is
NOT
used,
its reach
is
foreshortened. If
zero
sequence
current
compensation
is
used,
the
only remaining
variation
in
unit
reach
will be
due to
zero sequence
mutual
impedance
with a
parallel line.
These
factors
will
be
evident
from
the
following
equations
Ta
and lb
The
mho
units of
the CEYG51A
relay must
not
be
compensated
for
the zero
sequence
mutual
impedance
due
to
a
parallel line.
This
is because
reversal
mutual
in
the
parallel
line
could cause
the
who unit
to
operate
incorrectly
on
the
protected
line.
NO
ZERO
SEQUENCE
CURRENT
COMPENSATION
When
zero
sequence
current
compensation
is
NOT
used, the
effective
impedance
as seen
by the
relay
on
the faulted
phase for
a single
phase
to
ground
fault
at
the
far end
of
the
line
is:
z
+ (Z 0 ’
- Z 1 )C 0
ZI’
1
2C+C
I
o
a
Ia
where:
=
Positive
sequence
impedance
of the protected
line.
Z’ =
Zero
sequence
impedance
of
the protected
line.
z
m
=
Total zero
sequence
mutual
impedance
between
protected
line
and
parallel
line.
I “
= Zero
sequence
current
in the parallel
line,
taken
as positive
when
the
0
current
flow in
the
parallel
line
is in the
same
direction
as
the
current
in the protected
line.
‘a’
= Phase
A
current
in
the
relay.
C
= Positive
sequence
distribution
constant
I’/l.
C 0
=
Zero sequence
distribution
constant
10/10.
T
=
Tap setting
in percent.
K =
Design
Constant
100
for
the
1.0 ohm
basic
minimum
tap
200
for the
2.0 ohm
basic
minimum
tap
300 for
the
3.0 ohm
basic
minimum
tap
0
=
The aigle
the fault
current
lags the
fault
voltage.
To
insure
that the
relay
on
the faulted
phase
picks
up
for
a
fault
at the
remote
bus, the
maximum
per
cent
tap
setting
permissible
is:
T
=
KCos
(600_U)
r
(Z 0 ’ -
z 1 )C 0
ZI”
1
lb
1.25
L
Z 1
+ 2C ÷
C 0
+ Ta
I
17

GEK-26423
If
the
solution
to
equation
lb
yields
a
tap value
CT)
greater
than
100
percent,
this
implies
that
even
the
shortest
reach
setting
possible
(100
percent
tap)
will
suffice.
The
factor
1.25
introducted
in
equation
lb is
a
safety
factor.
In
order
to
extend
the reach
of the
relay
beyond
the
far
bus,
lower tap
settings
will
be
required.
If there
is
no
zero
sequence
mutual
impedance,
the
last
term
in
the
denominator
of
equation
lb becomes
zero.
If
there
is
mutual
impedance
existing
between
the
protected
line
and
several
other
circuits,
this
last
term
becomes:
z
i
om
0
Note
that
in
this
summation,
the direction
of
the
zero
sequence
current
flow
(I
“)
in
each
of
the
parallel
circuits
must
be
considered.
0
All voltages,
currents
and
impedances
in
the
above
equations
are
interins
of
secondary
quantities
based
on
the
CT
and
PT ratios
of
the protected
line.
This
applies
to
I
as
well
as
WITH
ZERO
SEQUENCE
CURRENT
COMPENSATION
When
zero
sequence
current
compensation
is used,
the
effective
impedance
as
seen
by the
relay
on
the
faulted
pase
for
a
single
phase
to
ground
fault
at
the
far
end
of the
line
becomes:
Z
I
++
3K’
10’
where:
xo’
-
Xl’
K’
3X 1 ’
The
per
unit
ritIo
of
zero
sequence
current
to
be
used
for
compensation.
To
insure
that
the
relay
on
the
faulted
phase
picks
up
for
a
fault
at
the
remote
bus, the
maximum
percent
tap
setting
permissible
is:
—
KCos
(60-0)
=
r
Z 0 I 0 ”
1.25
LZ 1 ’
+
1 a’
+
3K’I’
APPENDIX
II
MAXIMUM
PERMISSIBLE
REACH
SETTING
FOR
THE
CEYG51A
NO
ZERO SEQUENCE CURRENT
COMPENSATION
Under
some
system
conditions
it
is
possible
during
single
phase
to
ground
faults
in the
non-tripping
direction
that
one
or
the
other
of the
units
associated
with
the
unfaulted
phase
will
pick
up.
Since
this
can
result
in
a
false
trip,
it
is
necessary
to
limit
the
reach
setting
of
the
starting
units
to
prevent
them
from
picking
up
on
reverse
faults.
Equations
ha
and
Jib
give
this
limit.
K
(C
-
C)
T
=
z°
Cos
(150—A-9)
Ha
1
K 5
(C 0
-
C)
T
=
Cos
(A-0-30)
JIb
1
18

GEK-
264
23
The
system
constants
in
the
above
equations
should
be
evaluated for
a single
phase
to
ground
fault
in
the
non-tripping
direction
at
the
relay
terminals.
This
fault
location
is
designated
as
Fl
in
Figure
5.
T
=
Minimum
permissible
tap
setting in
percent.
C
=
Positive
sequence
distribution
constant
I’/I.
C 0
= Zero
sequence
distribution
constant
I0’/IO•
= System
positive
sequence
impedance
as
viewed
from
the
fault.
Z 0
=
System
zero
sequence
impedance
as
viewed from
the
fault.
9
= The
angle
of
the
system
positive
sequence
impedance
Z 1 .
K 5
=
Constant depending
on
the ratio
of
Z 0 /Z 1 .
See
curves
on
Figure
14.
A
= Angle
depending
on
the
ratio
of
ZQ/Z 1 .
See
curves
on
Figure
14.
The
system
constants
in
these equations
should
be
evaluated
for
a
single
phase
to
ground
fault
in
the
non-tripping
direction
at
the
relay terminals.
This
fault
location
is designated
as
Fl
in
Figure
5.
Under
some
system
conditions
it
is
possible
during
double
phase
to
ground
faults
in the
non-tripping
direction
that
the
unit
on
the
unfaulted
phase
will
pick
up.
Since
this
can result
in
a false
trip,
it is
necessary
to
limit
the
reach
setting
of
the
units
to
prevent them
from
picking
up
on reverse
double
phase
to
ground
faults.
Equation JIc
gives
this limit.
K
(C
-
C)
T
=
3Z 0
Cos
(9
-
60)
lic
where:
K =
Design
Constant
100
for
1.0
basic
minimum
tap
200
for
2.0
basic
minimum
tap
300
for
3.0
basic
minimum
tap
9
=
The
angle
of
the
system
zero
sequence
impedance
Z 0 .
All
other
terms
are
defined
above.
Note
that
C 0
and
C
in equation
tIc
have
the
same
values
as
they
have
in equations ha
and
lIb.
After
the values
of
T
have
been
calculated
for
equations
ha,
hib
and TIc
above,
the
largest
of
the
three
values
should
be
selected
and
then
some
margin,
such
as 10:
(not
10
percentage points),
should
be
added
to
this
setting. This
value
of tap
setting is
then
the
minimum
permissible
tap
setting
for
the
re
lay
at
the
terminal under
consideration.
If
any
(or
all)
of the
values
of
T
calculated from
the
three
equations is negative,
that
signifies
that
the
particular
equation
(or
equations) offers
no
limitation
on
the
minimum
permissible
tap
setting.
Aside
from
all
of
the
above,
the
relay
should
never
be
set on
a
tap
that
is
lower
than
10
percent.
All
voltages,
currents
and
impedances
in
the
above
equations
are
in
terms
of
secondary
quantities
based
on
the
CT
and
PT
ratios
of the
protected
line.
The
effects
of
arc
resistance
have
not
been
included
in
these
calculations.
19

GE
K-2
6423
APPENDIX
III
MAXIMUM
PERMISSIBLE
REACH
SETTING
FOR
THE
CEYG51A
WITH
ZERO
SEQUENCE
CURRENT
COMPENSATION
When
zero
sequence
current
compensation
is
used,
the
equations
of
Appendix
II
are
modified
as
follows:
for
single
phase
to
ground
faults
in
the
non-trip
direction:
K
[(3K
+
1)
C
-
C)1
--
S
°
Cos
(15O—A--O)
lIla
Zi
K
[(3K
+
1)
C
-
C)]
T
Cos
(A-O-30)
Ilib
Zi
for
double
phase
to
ground
faults
in
the
non-trip
direction:
K
L(3K’
+
1)
C
-
C)1
T
=
—-—-——
Cos
(9
-
60)
IlIc
3
where:
Xo’
—
Xl’
K’
3X
The
per
unt
ratio
of zero
sequence
current
to
be
used
for
1
compensation.
All
other
terms
are
as
defined
in
Appendix
II.
If
the
minimum
permissible
tap
setting
includiny
suitable
margins
as
determined
from
equations
THe,
IIb,
or
Ilic
above
are
positive
and
greater
than
the
maximum
permissible
tap
setting
as
determined
from
equation
Ic,
then
it
will
be
necessary
to
use
the
zero
sequence
directional
overcurrerit
supervising
relay,
Type
CFPGI6A.
Since
the
last
edition,
Figures
4
and
15
have
been
changed.
20