GE SFF201A User manual

GEK-90636D
INSTRUCTIONS
Static Frequency Relays
SFF2O1A, B
SFF2O2A, B
SFF2O4A, B

GEK-90636
rrabl
of
Contents
Page
Description
3
Application
4
Under
Frequency
4
Rate
of
Change
5
Over
Frequency
5
Load
Restoration
6
Specifications
7
DC
Control Voltage
7
AC Control
Voltage
7
AC
Measurement
Input
7
Settings
7
Environmental
7
Ratings
8
Burden
8
Contact Ratings
8
Settings
8
Displays
9
Functional
Description
9
Construction
10
Receiving,
Handling
and
Storage
10
Acceptance
Tests
10
General
10
Visual
11
TestEquipment
11
General
Testing
Considerations
11
Relay
Outputs
11
Tests
12
Over
Frequency
Relay
Tests
12
Over
Frequency
Test With
Variable
Frequency
Generator
12
Over
Frequency TestWith
Single
or Line
Frequency
13
Under
Frequency
Relay
Tests
14
Under
Frequency Test
With
Variable
Frequency
Generator
14
Under
Frequency Test
With
Single or
Line
Frequency
14
Rate
of
Change
for
Multiple
Setpoint
Models
Only
15
Rate
of
Change
Test
for
Variable
Frequency
Generators
15
Rate
of
Change Test
for
Single
or
Line
Frequency
16
Restore
Relay
Tests
16
Restore
Test
With
Variable
Frequency
Generator
17
Restore
Test
With Single
or
Line
Frequency
17
Installation
Procedure
17
Surge
Ground
18
Electrical
Tests
18
Settings
18
Trouble
Shooting
18
Servicing
19
Periodic
Checks
and
Routine
Maintenance
19
Renewal
Parts
20
Cover Photo:
8043796
2

GEK-90636
DESCRI PTION
The type SUP relays are
digital frequency relays that measure the system
frequency.
Three versions of the 5FF are available providinç one,
two,
or four
frequency setpoints. Each
S
the frequency measuring elements
is independent, and
can
be
independently
set
for under frequency,
over frequency, or restore operation,
and has
I form
C output contact. Each element may be set for any freQuency over the
ranse
of 40 to
79.9
Nz in 0.1 Hz steps in the SFF2O(-)A and 0.01 Hz
steps
in the
SFF2O(-)B. If a frequency setting outside of the acceptable range is made, that
frequency will be prevented from operating.
A simple rate-of-change (ROC) feature can
be
enabled on the multi-frequency
models. When this feature is enabled, an
output will be
produced
at the higher set
frequency if the next lower frequency setpoint is
reached
before
the timer associated
with the higher
set
frequency can time
out.
For example,
assume that a two setpoint
relay is set to operate at 59 Hz with an
0.75
second delay. and
at 58
Hz with
a I second
delay.
If 58 Hz is reached 0.5 seconds after 59 Hz is reached, the
output
relay
associated with the
59
Hz setting
will operate at that time rather than waiting until
the full 0.75 seconds has expired. Similar performance can
be
obtained between the
second and third setpoints and between
the third and fourth setpoints in the four
setpoint relay.
The minimum operating time for an under
frequency, over frequency, or restore
output to occur is 3 cycles. In addition, an adjustable timer is provided for each
frequency setpoint wherein
a delay can be added to the output. When used in the
under frequency or over frequency mode this time is
used to delay the output,
whereas it is used
to
prolong the
output
when the function is
used in the
restore
mode.
Timer ranges are shown below:
Mpdel Timer
Ranae SteDs
Sfl20(-)A:
0
to
1.55
seconds
.05
second
SF’F20(-)B: 1.0 to 255 milliseconds 1 millisecond
0.lto 25.5
seconds 0.lsecond
The
AC undervoltage cutoff function operates to block all outputs whenever the
input voltage is less than the undervoltage
cutoff setting. The function has a dropout
time
Sapproximately one-half
(1/2)
cycle and a pickup time dapproximately one (1)
cycle. The function
is adjustable over the range 535 to 95 percent inS percent
stçps.
Note that the percentage is based on 120 volts,
the
nominal rating
d’the relay. For
example, if the input voltage is 110 volts, and the cutoff level is
set to 50 percent,
cutoff will occur at 60 volts (50 percent of 120) rather than 55 volts (50 percent of
These
instructions do not
purport
to cover all details or variations in equipment nor to prouide for
evely
possible contingency to be met in connection with installation, operation or maintenance.
Should funher
information
be desired or should particular problems arise
which
are
not covered
sufficiently
flu’ the purchaseri purposes. the matter
should be
referred
to the General Electric
Company.
To the extent required the products described herein
meet
applicable ANSI, IEEE
and NEMA
standards, but no such assurance is given with respect
to local codes and
ordinances
because they
vaiy gnat4y.
a

GEK-90636
The
relays
can
be
powered
from
either
a
DC
or
AC
source.
External
connections
to
the SFF2O1,
SFF2O2
and
SFF2O4
relays
can
be
seen
in
Figures
1, 2
and
3,
respectively.
Table
I
summarizes the
models
available.
Table
I
Model
Case
Set
SFF
Size
Points
201
S2
1
202
M2
2
204
M2
4
APPlICATION
The
SFF
series
of
frequency
relays
can
be applied
wherever
an extremely
stable
device
is
required
for
the
accurate
detection
of
under
frequency or
over
frequency
conditions.
Under
Krequency
The
under
frequency trip feature
of
the
SFF
relays may
be
used
in load
conservation
schemes where
accuracy and
repeatability
of frequency
measurement
is
important. If
a system
disturbance
results
in
loss of
generating
capacity
such
that
load
exceeds
generation,
system frequency
will
start
to
decay
and
the
system
may
be
in
danger
of collapsing.
Under
frequency
relays
distributed
around
the system
can
be
used
to
detect
this
condition
and
to
disconnect selected
system
load
to
compensate
for
the
loss
of generation.
Sufficient
load
must
be
disconnected
to
enable the remainder
of the
system
to
recover to normal,
or
near
normal
frequency. In
this
way,
restoration
of the
entire
system
will
be facilitated.
An
overall
load
conservation
scheme
can
be
arranged
to
trip
off
selected
load
in
different
ways:
a.
Disconnect blocks
of
load
in
several
steps
with
each
step
occurring
at
a
successively lower
frequency.
b.
Disconnect
blocks
of
load
in
several
steps
on
a time
basis
at
one
frequency
level
so
that
some
load
is disconnected
as each
time
step is
reached.
c.
Any
combination of
the
above.
Each
frequency
measuring
element
in
the
SFF compares
the
period
of
each
cycle
of
the
voltage wave
against
a
crystal
reference and
requires three
successive
cycles
of
under
or over
frequency
before
the
delay
timer
is
started. If
the
input
voltage
wave is
distorted
so
as
to
affect
the period
of
the
wave,
and
if
this
distortion
persists
for the
total
time
setting, it
is
possible
for
the
relay
to make an
incorrect
measurement.
Longer
time delay settings
will
make
this less
likely
to occur.
On
the other
hand,
if
the
frequency
exceeds
the
setting
for
at
least
one cycle
after
the delay
timer
is
4

GEK-90636
started,
arid
before
the
time
delay
is
reached,
the
timer
will
be
immediately
reset
and
a
new
measurement
will
be
started.
An
important
consideration
in
the
application
of
frequency
relays
is
the location
of
the potential
source
from
which
the relay
makes
its
measurement.
It
is
generally
not
good
practice
to
supply
a
relay
from
a
potential
source
that
is
connected
to
one
bus
section
and
use
that
relay
to
disconnect
load
on
another
bus
section.
For
example,
the
voltage and
frequency
of
circuits supplying
motor
load
do
not
go
to
zero immediately
when
the
circuits
are
de-energized.
Rather,
both
the
voltage
and
the
frequency
decay
to
zero and
often
at
different
rates depending
on
the
characteristics
of
the
circuit
and
the
load.
A
frequency
relay
connected
to
such
a
circuit
could
produce
an
output
for
this
condition
if
the
voltage
stays above
the
voltage cutoff
setting
for
the
time delay
setting
(if
any).
If
the
relay
is
connected
to
disconnect
load
on
a
separate
bus section,
then
this load
will
be
inadvertently
disconnected.
A
substation
which
has
a
large
amount
of
motor
load
may
present
a
problem
of
time
coordination
in
load
shedding
applications.
If the
transmission
sources
to
the
substation
are tripped
out,
the
motor
load
would
tend
to
maintain
the voltage
while
the
frequency decreased
as
the motors
were slowing
down.
This
slow
decay
of
voltage
combined
with
a
fast
operating
under
frequency
relay
may cause
the
motor
breakers
to
trip
and
lock
out
unnecessarily.
In
an
unattended station,
restoration
of
the
motor
load would
not
then
be accomplished
by
simply
reenergizing
the transmission
sources.
‘This problem
could be
avoided
by
coordinating
the
settings
of
the
time
delay
of
the
under
frequency
trip
and
the level
of
the
undervoltage
cutoff
function.
The
SFF
relay may
also
be
used
in
an
industrial
installation
that
is
tapped
off
of
a
power company
transmission
circuit
that utilizes
high
speed
automatic
reclosing.
For
faults
on
the line,
both
ends of
the
line
will
be
tripped.
This
will
be
followed
by
a
high
speed
reclose.
It
is
important
for
the industrial
load
to
be
disconnected
prior
to
the
reclosure
to
prevent
damage
to
motors
andlor
generators
that may
have
slowed
down
during
the
interruption.
An
SFF
relay
at
the plant
could
be
used
to
detect
the
drop
in
frequency
that might
occur
during
the
time
that
the
transmission
line
is
open.
The
relay
could
be
used to
trip the
incoming
breaker
to
the
plant
to
separate
it
from
the
power
system
before
reclosing
takes
place.
Each
application
will
have
to be
analyzed
to
determine
the
amount
of
frequency
decay,
if
any,
that
will
occur
during
the
open circuit
period.
Rate
of
Change
The
rate
of
change
feature
is
available
only in
multi-setpoint
models
of
the
SFF
relays,
and
is
usable
only
between
two
adjacent
setpoints;
i.e., Fl
and
F2, F2
and
F3
or
F3
and F4.
This
feature
will
allow
load
to
be
shed
faster
if
the frequency
decays
at
a
rate
faster
than
was
anticipated
when
the
delay
timer
settings
were
determined.
The
rate of
change
feature
is
enabled
by
setting
the
appropriate
ROC switch
to
the
IN
position.
Over
Frequency
The
over
frequency
function
may
be
used
anywhere
that it
is
desired
to
detect
an
over
frequency
condition.
For
example,
it
can
be
used
to
protect
a
generator
against
operation
at
frequencies
above
rated
speed
that
could
be
caused
by an
inadvertent
load
rejection.
Another
possible
application
of
the over
frequency
function
is
in
schemes
to
be
used to
protect
a
generator
against
accidental
energization
at
sub
synchronous
speeds
or
on
turning
gear.
In
such
schemes
the over
frequency
function
would
be
used
to
remove
supplemental
protection
that
is
required
to
be
enabled
only
during
off-line
operation.
5

GEK-90636
CAUTION
It
should
be
recognized
when
applying
the
over
frequency
function in
this
fashion
that
a
loss of
I)C
to
the
relay
will
cause
the
output
relay
to
reset,
thus
enabling
the
associated
off-line
protection.
Load
Restoration
If
a
load
shedding
program has
been
successfully
implemented,
the
system
frequency
will
stabilize,
and
through
system
control
will
recover
to
normal.
The
recovery
to
normal
is
likely
to be
quite
slow
and
may
extend
over
a period
of
several
minutes.
As
the frequency
approaches
normal
the
restore
function
in
the SFF
relay
can
be
used
to automatically
begin
the
load
restoration
process.
The
amount
of load
that
can
be
restored
is determined
by the
ability
of
the
system
to
serve
it. The
availability
of
generation, either
locally
ol- through
system
interconnections,
determines whether
or not
the
shed
load
can
be successfully
restored.
A load
restoration
program
usually
incorporates
substantial time
delay,
which
must
be
provided
by
a timer
external
to
the
SFF
relay.
The
amount
of
time
delay
to
use
is
related
to
the amount of time
required
to
add
generation
or
to close
tie
lines
during
emergency
conditions.
Also,
both
the time
delay
and
the
restoration
frequency
setpoints
should
be
staggered
so that
all
of the
load
is
not
reconnected
at the
same
time.
Reconnecting loads
on
a distributed
basis
also
minimizes
power
swings
across
the
system
and
thereby
minimizes the
possibility
of initiating
a
new
disturbance.
Since
the
restoration timers
will
be
set
for
long
time
delays,
it
is
essential
that
they
do
not
reset
as
a result
of
transient
system
frequency
oscillations
that
may
momentarily
reset
the
restore
output
function. For
this
reason,
the
restore
function
is
provided
with
an
adjustable
time
delay
reset
before
the contacts
change
state
whenever
the
function
is
subjected to a
frequency
change
from
above
the
setpoint
to
below
the setpoint.
This
delay
is adjustable
and should
be
kept
very
brief,
only
long
enough
to
ride over
momentary
under
frequency conditions.
The
restore
frequency
setting
of the
function
will
most
likely
be
at
or
very
close
to
rated
frequency. If the
continuous
variations in
normal
frequency
are such
that
the
restore
function
output
relay
will
pick
up and
drop
out
continually,
the
life
of the
relay
may
be
shortened. To
prevent
this,
a
contact
converter
designated
CC
is
provided
to control
the
restore
output.
CC
is to
be energized
by an
external
device
after
load
shedding has
occurred
and
when
it is
desired
to
restore
load.
CC
should
be
kept
energized
until
all
of the
load
that
was
shed
has
been
restored
at
which
time
it
should
be
de-energized.
In
this
way,
the
restore
output
relay
will
only
be
operated
after
an
under
frequency
condition
has
been
detected and
until
the
load
that
was shed
has
been
restored. During
normal
frequency conditions,
CC
will
be
de-energized
and
the
restore
function
will
not operate
due to
minor
changes
in
frequency.
6

GEK-90636
SPECIFICATIONS
DC
Control
Voltage
Nominal
48, 110,
125,
220,
250
Minimum
37
Volts
Maximum
280 Volts
AC Control
Voltage
Nominal
110-120
Vrms
Minimum
45
Vrms
Maximum
132
Vrms
AC Measurement
Input
Nominal
120
Vrms
Minimum
42
Vrms
(35%
of
nominal)
Maximum
132
Vrms
(110% of
nominal)
Settings
Frequency
SFF2O(-)A:
Setpoint
40.0
to
79.9
Hz in
0.1
Hz
steps
SFF2O(-)B:
Setpoint
40.0 to
79.9 Hz
in 0.01
Hz
steps
Repeatability
±0.002
Hz
Timing
SFF2O(-)A:
Setpoint
0
to 1.55
seconds
in 0.05
second
steps
SFF2O(-)B:
Setpoint
1 to
255
milliseconds in 1
millisecond steps
Setpoint
0.lto 25.5
seconds in
0.1
second
steps
Repeatability
± 3%
Undervoltage
Setpoint
35% to
95%
in 5%
steps
based
on l2OVrms
nominal
Setpoint
Accuracy ±5%
Repeatability
±3%
of
setting
from
35% to
90%
Rate
of
change
(multi-setpoint
models
only)
Frequency
1
to
frequency
2:
IN
or
OUT
Frequency
2
to frequency
3:
IN
or OUT
Frequency
3 to
frequency
4:
IN
or OUT
Environmental
Operating
-20°C
to
+55°C
95% relative
humidity
(noncondensing). Note
that
the
unit
will
not malfunction,
nor
be damaged,
in
ambient
up to
+
65°C
Storage
-40°C
to + 75°C
95%
relative
humidity
(noncondensing)
Surge
ANSI
C37.90
(SWC
and Fast
Transient)
IEC 255
GE RFI
7

GEK-9063
RATINGS
Burden
Table
II
Burdens
Model
Case
Set Power Supply
Measurement
SFF
Size
Points
DC
AC
AC
________
VA
VA
48
125
250
120
201 S2
1
3.2
3.5 6.3 8.1
1
202
M2
2
4.9
5.2
8.0
10.6
1
204
M2
4
8.4 8.7
11.5
15.7
1
Contact
Ratings
Make
and carry
30
amps
for
1 second.
DC
Break
60
Watts
Resistive
Break
25
VA
(40
ms
L/R)
AC
277
Volts
maximum
5
Amperes
Target
supervision
unit
0.1
amp
operate
level
with
less
than
0.6
volt
drop
at 30
amps.
SWFTI
NGS
The
following
settings,
which
must
be
set
in
each application,
are
made
from
the
front
of
the
relay
without
the
need
for
pulling
boards
or
removing
the
nameplate.
It
is
only
necessary
to remove
the
front
cover
from
the relay.
Frequency
A
three
or
four digit thumbwheel
switch
on
the front
panel
allows
the
frequency
of each
setpoint
to
be
set.
Note:
if
a
setting
is
made
outside
of the
stated
range,
that
frequency
setpoint
will
be
prevented
from
operating.
Function
A
three
position
slide
switch
permits
the
choice of
under,
over,
or restore
modes of
operation.
When
the
restore
mode
is chosen
the timer
is switched
to
dropout
delay and
the contact
converter
input
is enabled.
Rate
of
Change
(Multi
frequency
models
only)
A
two position
recessed
switch
selects
the
rate of
change
function.
This
function
is
only
valid for
under
frequency
operation.
It
is
disabled
when
over
frequency
or
restore
modes
are
chosen.
Time
Delay
An
array
of
two-position
toggle
switches
allows
setting
the
output
delay.
The
setting
is equal
to
the
sum of
the
switches
in
the
UP
position.
Voltage
Cutoff
An array
of
two-position
toggle
switches
calibrated
in 5%
steps
is
used
to choose
the
undervoltage cutoff
level.
The
cutoff
setting
is equal
to
the
sum
of
the
switches
in the
UP
position.
8

GEK-
90636
DISPLAYS
jp
The
trip indicators
are
red LED’s
which are supervised
by
the
passage
of trip
current.
One
is
provided
for
each
tripping
element.
Table
HI
Model
Target
Description
201
Fl
Frequency
1
output contact
operated
202
Fl
Frequency
I
output
contact operated
ROC
Rate of
change
caused
Fl
contact
to
operate
F2
Frequency
2
output
contact
operated
204
Fl
Frequency
1
output
contact
operated
ROC
Rate
of
change
caused
Fl
contact
to
operate
F2
Frequency
2
output
contact
operated
ROC
Rate
of
change
caused
F2
contact
to
operate
F3
Frequency
3
output
contact
operated
ROC
Rate
of
change
caused
F3
contact
to
operate
F4
Frequency
4
output
contact
operated
Test
Amber
LED’s
light
to indicate
when
the
frequency
detection
circuit
has
an
output and
if an output relay
is
energized
(TB).
In
Service
A normally
lit green
LED indicates
the
regulated
DC
and
start-up
circuity
are
operational.
FUNCTIONAL
DESCRIPTION
The
potential
source
connected
to studs
5 and 6
is
stepped
down
to
6.9 VRMS
filtered
and converted
to a
square wave.
It
is
this square
wave
that
is
measured
by
the frequency element.
The frequency
measuring
circuit
compares
the
period
of the
incoming
square
wave
against
a
crystal
reference.
If
the source
frequency
differs
from
the
setpoint
for
more
than
three
consecutive periods
or cycles
the circuit
gives
an output. If
the
under
voltage supervision
has not
operated
this output
starts
a time
delay
(which
can
be
set
to
0)
which in
turn drives
the
output
contact.
The
rate of
change
feature if
selected
will
bypass
the time
delay if
the
next lower
frequency
element
has
operated.
The
rate of change
path
is
F4
to F3,
F3
to F2,
and F2
to Fl. Therefore when
the
frequency
settings
are made,
F4
should
be
less
than F3,
etc.
This does
not
preclude
setting
one element
for
restore, another
for
over, and
the remaining
two
for under
in
a
four
frequency relay.
It is
only
important
that the under
frequency
elements
be
adjacent
(F1-F2,
F2-F3,
F3-F4)
if rate
of
change is
desired. Block
diagrams
of
each
model can
be
found
in
Figures
4,
5
and
6. Internal
connection
diagrams
for
each
model
can be
found
in
Figures 10,
11 and
12.
9

GEK-90636
CONSTRUCTION
The components
of
the
relay
are
mounted
on
a cradle assembly
that
can easily
be
removed
from
the
relay
case.
The
cradle
is
locked
in the
case
by
latches
at
the top
and
bottom.
The
electrical
connections between the
case blocks
and
the cradle
b1ocks
are
completed
through
removable
connection
plugs to
permit
testing
the
relay
in
its
case.
The
cover is
attached
to the
front
of
the case
and
includes
two
interlocking
arms
that
prevent
the cover
from
being
replaced
until
the
connection
plugs
have
been inserted.
The
case
is
suitable
for semi-flush
mounting
on
panels.
Hardware
is
available
for
all
panel
thicknesses
up
to two
inches.
A
panel
thickness of 1/8
inch
will
be
assumed
unless
otherwise
specified
on the
order.
Outline
and
panel
drilling
dimensions
for
the
SFF2O1
are
shown
in
figure
8 and
for
the
SFF2O2
and 204
figure
7.
The
printed
circuit
boards are
mounted
behind
the nameplate
and
can
be accessed
by
removing
the
four screws
securing
the
nameplate.
The
boards
are mounted
horizontally in
guides.
Each
board
is labeled
to
correspond
to
a given location.
Use
GE
part number
286A2847P1
card
puller
or other
suitable means
to
remove
the
circuit
boards.
If
you
do
not have
a
card
puller,
be
careful
not
to damage
or
bend
any
components when removing the
boards.
The
output
relays
are
mounted
in
sockets
on
a
board
fixed to
the
back
of
the
cradle.
If
a relay requires
replacement
unclip the
retaining
wire
and pull
the
relay
out
of
the
socket.
The
input
transformer
is
mounted
on
the bottom
plate
of the
relay
cradle.
RECEIVING,
HANDLING
AND
STORAGE
This
relay
contains
electronic
components
that
could
be
damaged
by
electrostatic
discharge
currents if
those
currents flow through
certain
terminals
of
the
components.
The
main
source
of
electrostatic
discharge
currents
is
the
human
body,
and the
conditions
of low humidity,
carpeted
floors
and
isolating
shoes
are
conducive
to the
generation
of
electrostatic
discharge
currents.
Where these
conditions
exist,
care should
be
exercised
when
removing
and
handling
the
modules
to
make
settings
on
the
internal
switches.
The
persons
handling
the
module
should
make
sure
that
their body
has
been
discharged, by touching
some
surface
at
ground
potential,
before
touching
any
of
the
components
on
the modules.
These
relays,
when not
included
as
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
damage
resulting
from
handling
is
evident,
file a
damage
claim
at
once with
the transportation
company
and
promptly
notify
the
nearest
General
Electric Sales Office.
The
relays
should
be stored
in
their
original
cartons.
If
the relays
are not
to
be
installed
immediately, and
in
a
place
that
is free from
moisture,
dust
and metallic
chips.
ACCEPTANCE
TESTS
General
The
relay should
be examined
and tested
upon
delivery
to
insure
that
no
damage
has been
sustained
in
shipment
and
that
the
relay
is
functioning
correctly.
10