GE MDP User manual

I
l
MDP
DIGITAL
TIME
OVERCURRENT
RELAYING
SYSTEM
s
r
.
N
:
•
5
:
*
r
>
SRW
•
DCi
-
AY
t
‘
'
*
’
•
1
•
tf
'
&
y
I
:
X
513
/
*
i
:
•
v
$
s
*
f
|
®
“
S
.
.
I
,
5
mm
&
:
}
*
V
MODEL
MOP
2120000
6
AMPS
48
/
136
VDO
i
Vp
«
100802
QEK
\
•
.
v
.
-
•
.
•
:
*
•
'
-
-
f
=
‘
•
‘
A
..
.
J
«
•
i
Wli
>
'
;
>
•
V
.
.
-
’
*
7
.
i
Courtesy of NationalSwitchgear.com

GEK
-
100682
Table
of
Contents
PRODUCT
DESCRIPTION
NOMENCLATURE
APPLICATION
TECHNICAL
SPECIFICATIONS
Ranges
and
Settings
OPERATING
PRINCIPLES
Inputs
External
Inputs
COMMUNICATIONS
PORT
Installation
/
Replacement
of
a
Communications
Upgrade
Card
.
,
MEASUREMENT
Inverse
Time
Unit
Instantaneous
Unit
4
5
5
6
8
9
9
9
9
9
10
10
12
Changing
Settings
Settings
12
13
Pickup
TOC
Pickup
IOC
Time
Dial
'
Curve
Selection
IOC
Delay
Communications
Address
OUTPUT
CONTACT
CONFIGURATION
13
13
13
13
13
13
14
14
Display
and
Reset
Self
Test
and
Error
Routines
CONSTRUCTION
Internal
Connection
Diagram
Displays
RECEIVING
,
HANDLING
,
&
STORAGE
ACCEPTANCE
TESTS
Visual
Inspection
Electrical
Tests
15
15
15
15
15
16
16
16
16
Inverse
Time
Unit
Instantaneous
Unit
Ground
Unit
18
18
18
MDP
-
Link
Software
,
Overview
System
Reuirements
Installation
GENERAL
OPERATION
Main
Horizontal
Menu
Bar
.
Pull
Down
Menus
Dialog
Boxes
List
Boxes
Entering
Text
and
Numbers
PROGRAM
OPERATION
Main
Menu
Relay
Functions
18
18
19
19
19
19
19
20
21
21
21
21
21
Login
2
Courtesy of NationalSwitchgear.com

GEK
-
100682
|
|
|
lOgout
22
Hang
up
phone
request
relay
Data
request
Fault
data
Reset
fault data
Breaker
status
Trip
breaker
Close
breaker
Local
functions
go
to
DOS
Setup
Communication
port
number
Dial
type
Modem
connection
time
Relay
parameters
..
.
.
Add
relay
to
list
dElete
relay
list
display
mode
Memory
available
...
Help
Exiting
MDP
-
LINK
INSTALLATION
,
.
PERIODIC CHECKS
AND
ROUTINE
MAINTENANCE
22
22
22
23
.
23
23
24
24
24
24
24
24
24
25
25
25
26
.
<
'
26
26
26
26
27
m
Cover
Photo
:
8919557
These
instructions do
not
purport
to
cover
all
details
or
variations
in
equipment
nor
provide
for
everypossible
contingency
to
be
met
in
connection
with
installation
,
operation
or
maintenance
.
Should
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
(
USA
)
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
vary
greatly
.
§
1
m
3
Courtesy of NationalSwitchgear.com

GEK
-
100682
MDP
DIGITAL
TIME
OVERCURRENT
RELAYING
SYSTEM
PRODUCT
DESCRIPTION
Phase
and
ground
current
metering
;
Operating
time
and
fault
current
of
the
last
trip
.
MDP
relays
digital
,
Type
microprocessor
-
based
,
non
-
directiona
!
overcurrent
relays
that
protect
against
phase
-
to
-
phase
and
phase
-
to
-
ground
faults
.
are
Breaker
status
•
v
>
:
'
Breaker
operation
(
RS
232
and
RS
485
versions
only
)
The
MDP
relay
performs
the
following
functions
:
The
MDP
series
relays
include
four
measuring
units
,
one
for
each
of
the
three
phase
currents
and
an
additional
one
for
ground
or
residual
current
,
Each
of
the
four
measuring
units
includes
a
time
and
an
instantaneous
overcurrent
unit
.
The
phase
settings
arc
combined
so
that
all
phase
units
are
set
the
same
.
Inverse
overcurrent
,
including
four
characteristic
curves
,
and
four
values
of
definite
time
protection
,
as
well
as
instantaneous
overcurrent
protection
with
programmable
delay
;
Phase
and
ground
current
measurement
;
CURRENT
RANGES
Nominal
Current
Inverse
Time
Unit
Instantaneous
unit
«
*
(
In
)
(
Is
)
Ground
1
,
5
to
13
,
125
Amps
0.5
to
4.375
Amps
0.1
to
0.875
Amps
Phase
5
Amp
Nominal
1.5
-
13.125
Amps
0.5
-
4.375
Amps
1
to
31
x
Is
(
All
Relays
)
0.5
-
4.375
Amps
0.3
to
2.625
Amps
0.1
to
0.875
Amps
0.05
to
0.4375
Amps
(
'
A
AMP
CT
)
1
Amp
Nominal
0.3
-
2.625
Amps
£
V
-
The
pickup
value
for
the
instantaneous
unit
can
be
adjusted
between
1
and
31
times
the
value
selected
for
the
inverse
-
time
unit
.
produced
(
A
)
by
an
instantaneous
unit
or
an
inverse
unit
,
or
(
B
)
by
phase
or
ground
.
That
selection
is
made
by
means
of
a
switch
behind
the
right
lower
side
of
the
nameplate
.
An
alarm
output
is
provided
,
to
signal
a
critical
alarm
such
as
power
-
supply
failure
or
self
-
check
failure
.
An
output
contact
is
provided
to
close
the
breaker
from
a
command
issued
via
the
Communications
Channel
.
The
instantaneous
unit
can
be
disabled
by
adjusting
the
setting
to
zero
(
0
)
times
the
inverse
value
.
The
MDP
relay
has
two
trip
output
relays
,
which
can
be
selected
to
indicate
whether
a
trip
has
been
©
4
Courtesy of NationalSwitchgear.com

GEK
-
100682
©
NOMENCLATURE
1
MDP
0
000
A
No
communications
or
control
inputs
(
Block
Ground
,
Block
Instantaneous
,
Breaker
Status
)
Control
inputs
and
communications
upgrade
socket
CommNet
MOD
BUS
RTU
RS
232
RS
485
0
I
2
3
4
5
5
Amp
Nominal
,
0.5
to
4.375
Amps
Ground
5
Amp
Nominal
,
1.5
to
13.125
Amps
Ground
5
Amp
Nominal
,
0.1
to
0.875
Amp
Ground
1
Amp
Nominal
,
0.1
to
0.875
Amp
Ground
1
Amp
Nominal
,
0.3
to
2.625
Amp
Ground
1
Amp
Nominal
,
0.05
to
0.4375
Amp
Ground
5
Amp
Nominal
,
0.5
to
4.375
Amp
Ground
/
Phase
1
2
3
4
5
«
;
6
7
1
24
-
48
VDC
(
19
to
60
VDC
)
48
-
125
VDC
/
AC
(
38.5
to
150
VDC
/
AC
)
35
to
120
AC
110
-
250
VDC
(
88
to
285
VDC
)
85
to
240
AC
D
Revision
Level
2
3
APPLICATION
Time
-
overcurrent
relays
are
used
for
the
protection
of
feeders
,
transmission
lines
,
alternating
-
current
machines
and
transformers
,
and
for
numerous
other
applications
where
accurate
measurement
of
current
and
timing
is
necessary
.
The
operating
tune
of
associated
protective
devices
should
be
considered
in
the
selection
of
a
time
-
current
characteristic
for
a
particular
application
,
to
ensure
proper
coordination
with
a
minimum
of
circuit
isolation
.
Four
basic
time
-
current
characteristics
are
available
in
Type
-
MDP
relays
.
short
-
circuit
current
flowing
through
any
given
relay
is
more
dependent
upon
the
location
of
the
fault
relative
to
the
relay
than
on
the
system
generation
setup
at
the
time
of
the
fault
.
The
extremely
inverse
-
time
-
current
characteristic
shown
in
Figure
4
is
preferred
for
applications
where
sufficient
time
delay
must
be
provided
to
allow
a
re
-
energized
circuit
to
pick
up
an
accumulated
cold
load
without
unnecessary
tripping
on
inrush
currents
.
Distribution
-
feeder
circuits
are
a
good
example
of
such
applications
,
and
the
extremely
-
inverse
characteristic
is
best
suited
to
such
applications
because
it
more
nearly
approximates
typical
power
-
fuse
and
fuse
-
cutout
characteristics
.
m
The
inverse
-
time
-
current
characteristic
curves
are
shown
in
Figures
1
,
2
and
5
.
Figure
5
depicts
the
BS
142
inverse
curve
and
applies
to
the
1
Amp
model
relays
only
.
These
relays
are
generally
applied
where
the
short
-
circuit
-
current
magnitude
is
dependent
largely
upon
the
system
generating
capacity
at
the
time
of
the
fault
.
The
very
inverse
-
time
-
current
characteristic
shown
in
Figure
3
is
generally
applied
where
the
magnitude
of
The
general
practice
for
grounded
-
distribution
-
system
protection
is
to
use
three
phase
-
overcurrent
functions
for
protection
against
interphase
faults
and
a
ground
/
residual
overcurrent
function
for
single
-
phase
-
to
-
ground
faults
.
5
Courtesy of NationalSwitchgear.com

GEK
-
100682
The
use
of
a
separate
grounid
-
overcurrent
function
is
advantageous
because
it
can
generally
be
adjusted
to
provide
faster
and
more
sensitive
protection
for
single
-
phase
-
to
-
ground
faults
'
than
the
phase
-
overcurrent
functions
.
Typical
connections
for
such
an
application
are
shown
in
Figures
9
and
10
,
This
safety
factor
can
be
reduced
to
0.07
second
if
the
time
unit
is
instead
set
to
the
desired
time
accurate
tests
.
by
#
The
instantaneous
-
overcurrent
unit
can
be
applied
in
many
instances
to
reduce
the
fault
-
clearing
time
for
high
-
fault
currents
.
This
unit
is
normally
set
to
pick
up
only
on
internal
faults
in
the
protected
zone
.
Significant
transient
overreach
can
be
experienced
under
certain
conditions
,
and
this
must
be
taken
into
account
by
selecting
a
pickup
setting
that
is
higher
than
that
which
would
be
dictated
by
the
maximum
steady
-
state
external
-
fault
current
.
The
pickup
setting
of
the
MDP
time
unit
should
be
chosen
so
that
it
will
operate
for
all
short
circuits
in
the
protected
zone
,
and
also
provide
back
-
up
protection
for
short
circuits
in
the
immediately
-
adjacent
system
element
when
possible
.
The
time
-
unit
pickup
should
be
set
low
enough
to
ensure
that
the
minimum
fault
current
is
at
least
1.5
times
the
setting
.
IMPORTANT
NOTE
If
one
unit
(
instantaneous
or
inverse
)
operates
,
the
other
unit
(
inverse
or
instantaneous
)
will
also
operate
.
The
MDP
’
s
fault
report
will
record
the
first
fault
that
occurred
.
When
the
fault
is
cleared
the
MDP
’
s
fault
LED
’
s
will
display
Phase
-
Phase
,
Phase
-
Ground
,
Instantaneous
and
inverse
time
faults
.
See
display
section
on
how
to
interpret
the
display
for
various
fault
conditions
.
The
MDP
will
generate
a
new
fault
report
when
the
fault
current
drops
below
the
pick
-
up
value
and
a
new
fault
occurs
.
The
time
-
delay
adjustment
of
the
time
unit
should
be
chosen
to
assure
selectivity
with
the
protection
on
the
adjacent
system
elements
.
This
adjustment
should
be
made
for
the
condition
that
yields
maximum
fault
current
at
the
relay
location
.
The
time
delay
is
determined
by
the
adjacent
relay
operating
time
for
this
condition
,
plus
a
coordinating
time
allowance
that
includes
the
adjacent
circuit
-
breaker
maximum
operating
time
and
a
safety
factor
to
accommodate
any
uncertainties
.
Since
the
MDP
time
unit
has
insignificant
overtravel
,
the
only
relay
variation
that
needs
consideration
in
the
safety
factor
is
the
tolerance
on
the
time
curves
.
A
0.17
-
second
safety
factor
is
generally
used
if
the
relay
time
is
determined
by
selecting
a
time
-
dial
setting
from
the
time
curves
.
i
Contact
converter
input
CC
1
and
the
output
-
select
switch
of
the
MDP
allow
a
Zone
Selective
Interlocking
of
the
MDP
relays
.
This
scheme
provides
instantaneous
operation
(
with
a
minimum
time
delay
)
of
the
upstream
relay
for
faults
between
the
upstream
and
downstream
relays
.
Refer
to
Figure
11
for
a
typical
scheme
and
settings
considerations
.
Note
that
all
the
feeders
must
be
radial
,
with
no
,
or
very
weak
,
source
.
TECHNICAL
SPECIFICATIONS
Nominal
frequency
:
25
/
50
/
60
Hz
t
!
Nominal
current
:
1
or
5
amps
24
-
48
VDC
(
19
to
60
VDC
)
48
-
125
VDC
/
AC
(
38.5
to
150
VDC
/
AC
)
35
to
120
AC
110
-
250
VDC
(
88
to
285
VDC
)
85
to
240
AC
0.1
-
0.875
/
0.3
-
2.65
=
0.09
/
,
2.8
°
at
60
Hz
(
2.25
VA
at
5
A
)
0.1
-
0.875
/
0.3
-
2.65
=
0.09
/
,
2.4
°
at
50
Hz
(
2.25
VA
at
5
A
)
0.5
-
4.375
/
1.5
-
13.25
=
0.01
/
,
11.5
°
at
60
Hz
(
0.25
VA
at
5
A
)
0.5
-
4.375
/
1.5
-
13.25
=
0.01
/
,
9
,
7
°
at
50
Hz
(
0.25
VA
at
5
A
)
Less
than
3
watts
at
all
voltages
,
quiescent
Less
than
4.5
watts
at
maximum
voltages
Auxiliary
power
supply
:
AC
Burden
:
DC
6
Courtesy of NationalSwitchgear.com

GEK
-
100682
-
20
°
to
+
65
°
C
(
-
40
°
C
available
upon
request
)
-
40
°
to
+
65
°
C
Operating
:
Storage
:
Temperature
:
Overcurrent
Ratings
:
2
x
In
Three
Second
;
50
x
In
One
Second
:
100
x
In
Continuous
:
RATINGS
I
/
t
CT
34500
87500
13600
1
AMP
5
AMP
*
1
AMP
SPECIAL
*
Models
MDPx
6
have
a
sensitive
ground
CT
.
Relative
Humidity
:
Up
to
95
%
without
condensing
<
:
Accuracy
:
Operating
Value
:
Operating
Time
:
5
%
5
%
or
0.025
seconds
,
whichever
is
greater
Repeatability
:
Operating
Value
:
Operating
Time
:
1
%
2
%
or
0.025
seconds
,
whichever
is
greater
Output
and
Trip
Contacts
:
Closing
:
1
Contact
will
close
and
conduct
up
to
a
maximum
of
30
amps
for
tripping
duty
at
control
voltages
up
to
300
VDC
.
The
output
contact
is
also
rated
for
Capacitive
trip
devices
.
Interrupting
:
50
watts
resistive
with
a
maximum
of
2
amps
and
300
VDC
Continuous
:
5
amps
,
with
300
VDC
maximum
25
-
70
Hz
(
Note
:
responds
to
RMS
values
of
harmonics
to
600
Hz
)
Frequency
operating
range
:
Communications
Address
:
002
to
998
r
.
'
T
-
rv
§
NOTE
Interference
suppression
ground
connection
This
connection
should
be
as
short
as
possible
,
to
assure
maximum
protection
,
conductors
are
recommended
.
The
MDP
relay
contains
high
-
frequency
interference
protection
consisting
of
a
series
of
capacitors
connected
between
the
input
terminals
and
the
case
,
Braided
#
12
AWG
The
case
stud
of
the
relay
should
be
connected
to
ground
,
so
these
interference
suppression
circuits
can
perform
their
protective
function
.
7
Courtesy of NationalSwitchgear.com

GEK
-
100682
RANGES
AND
SETTINGS
The
following
indicates
the
ranges
of
standard
models
.
Nominal
Currcntlnverse
Time
Unit
5
Amperes
Phase
Unit
Models
(
1
-
3
)
Phase
Unit
:
1.5
to
13.125
Amps
,
in
cumulative increments
of
0.375
,
0
,
750
,
1
,
50
,
3.0
,
6.0
A
Ground
Unit
,
model
1
:
0
,
5
to
4
,
375
Amps
,
in
cumulative
increments
of
0.125
,
0.250
,
0
,
50
,
1
,
0
,
2.0
A
Ground
Unit
,
model
2
:
1.5
to
13.125
Amps
,
in
cumulative increments
of
0.375
0.750
,
1
,
50
,
3.0
,
6.0
A
Ground
Unit
,
model
3
:
0.1
to
0.875
Amp
,
in
cumulative increments
of
0.025
,
.
0.050
,
0
,
10
,
0.2
,
0.4
A
v
-
5
Amperes
Phase
Unit
Model
(
7
)
Phase
Unit
:
0.5
to
4
,
375
Amps
in
cumulative
increments
of
0.125
,
0.25
,
0.50
,
1.0
,
2.0
A
Ground
Unit
,
model
7
:
0.5
to
4.375
Amps
in
cumulative increments
of
0.125
,
0.250
,
0.50
,
1.0
,
2.0
A
Nominal
Current
Inverse
Time
Unit
1
Ampere
Phase
Unit
Models
(
4
-
6
)
Phase
Unit
,
models
4
-
6
;
0
,
3
to
2
,
625
Amps
in
cumulative
increments
of
0
,
075
,
0.150
,
0.30
,
0.60
,
1.20
Ground
Unit
,
model
4
:
0
,
1
to
0.875
Amp
in
cumulative
increments
of
0.025
,
0.050
,
0.10
,
0.2
,
0.4
A
Ground
Unit
,
model
5
:
0.3
to
2.625
Amps
in
cumulative increments
of
0.075
,
0.150
,
0.30
,
0
,
6
,
1.2
A
Ground
Unit
,
model
6
:
0.05
to
0.4375
Amp
in
cumulative increments
of
0.0125
,
0.0250
,
0.050
,
0.1
,
0.2
I
*
-
*
Time
Delay
(
TOC
)
(
independent
for
phase
and
ground
)
Instantaneous
Unit
Time
Delay
(
independent
for
phase
and
ground
)
Depends
on
the
curve
selected
,
Five
Inverse
Time
curves
are
available
(
see
Figures
1
,
2
,
3
,
4
,
and
5
)
as
well
as
four
definite
times
(
maximum
time
2
,
4
,
6
,
8
seconds
)
,
all
in
the
same
relay
.
0
-
1.55
seconds
in
50
-
millisecond
steps
.
Phase
Operating
Curves
Curve
Selection
i
Inverse
/
BS
142
*
(
for
1
Amp
models
)
,
Long
Time
Inverse
,
Veiy
Inverse
,
and
Extremely
Inverse
.
Four
families
of
definite
time
characteristics
,
with
maximum
values
of
2
,
4
,
6
,
and
8
seconds
Instantaneous
Unit
Pickup
(
independent
for
phase
and
ground
)
1
-
31
times the
pickup
of
the
TOC
setting
.
Setting
of
zero
(
0
)
disables
instantaneous
unit
(
X
)
no
multiples
selected
,
Between
each
family
of
curves
,
a
specific
curve
can
be
selected between
0.5
and
10
in
cumulative
steps
of
0
,
5
,
1
,
2
,
2
and
4
for
5
Amp
relays
.
A
1
Amp
model
'
s
range
is
from
0.05
to
1.0
in
cumulative
steps
of
0.05
,
0.1
,
0
,
2
,
0
,
2
,
and
0
,
4
.
i
8
Courtesy of NationalSwitchgear.com

GEK
~
100682
©
Ground
Operating
Curves
Curve
Selection
EXTERNAL
INPUTS
Three
external
inputs
are
provided
.
One
,
when
energized
,
blocks
tripping
by
the
ground
units
.
The
second
blocks
the
phase
and
ground
instantaneous
trip
elements
when
it
is
energized
.
The
third
,
when
energized
,
indicates
that
the
Breaker
Status
is
"
closed
"
.
Diode
bridges
are
provided
on
all
inputs
;
thus
they
can
all
be
actuated
by
either
switched
-
to
-
positive
depending
on
the
polarity
connected
to
the
stud
.
These
inputs
can
be
energized
by
either
AC
or
DC
.
Inverse
/
BS
142
*
(
for
1
Amp
models
)
,
Long
Time
Inverse
,
Very
Inverse
,
and
Extremely
Inverse
,
Four
families
of
definite
time
characteristics
,
with
maximum
values
of
2
,
4
,
6
,
and
8
seconds
*
Between
each
family
of
curves
,
a
specific
curve
can
be
selected
between
0.5
and
10
in
cumulative
steps
of
0.5
,
1
,
2
,
2
,
and
4
for
5
amp
relays
.
A
1
amp
model
'
s
range
is
from
0.05
to
1.0
in
cumulative
steps
of
0.05
,
0.1
,
0
,
2
,
0.2
,
and
0
,
4
.
©
switched
-
to
-
negative
,
or
*
BS
142
is
the
INVERSE
curve
of
the
one
-
amp
model
.
NOTE
that
the
Breaker
Status
and
Block
Ground
inputs
,
CP
-
7
and
CP
-
6
respectively
,
must
be
switched
by
the
same
polarity
,
since
they
share
a
common
ground
(
CP
-
8
)
.
Communications
Address
•
<
;
A
setting
of
000
indicates
no
communications
and
sets
the
default
display
to
phase
A
Current
.
002
to
998
.
COMMUNICATIONS
PORT
The
MDP
relay
has
a
communications
feature
that
permits
easy
installation
of
various
communications
interface
modules
.
All
values
are
adjusted
with
dip
switches
located
at
the
front
of
the
relay
,
except
the
communications
address
,
which
is
located
on
the
rear
of
the
cradle
.
m
INSTALLATION
/
REPLACEMENT
OF
A
COMMUNICATIONS
UPGRADE
CARD
NOTE
1
.
To
install
a
communications
upgrade
card
or
replace
an
existing
card
,
begin
by
removing
the
relay
from
the
case
,
Refer
to
Figures
14
-
19
during
the
following
procedure
.
For
RS
232
and
RS
485
all
relays
will
respond
to
address
001
.
2
.
Before
continuing
,
connect
an
approved
wrist
grounding
strap
to
ground
,
to
discharge
any
static
electricity
in
your
body
that
could
damage
the
electronics
of
the
MDP
relay
.
A
wrist
strap
is
provided
with
the
communications
card
kit
.
The
wrist
strap
must
provide
a
"
safe
"
high
resistance
to
ground
.
OPERATING
PRINCIPLES
INPUTS
m
The
secondaiy
current
from
the
current
transformers
of
the
protected
line
is
connected
to
the
relay
and
immediately
reduced
via
the
internal
current
transformers
.
The
secondaries
of
the
relay
'
s
current
transformers
are
connected
across
input
resistors
,
yielding
a
voltage
proportional
to
the
relay
input
current
,
3
.
Remove
four
screws
attaching
the
nameplate
settings
board
and
the
NOMEX
insulation
paper
to
the
relay
cradle
.
(
Cover
photograph
)
Note
that
there
are
four
metal
spacers
between
the
nameplate
and
the
settings
board
.
Do
not
lose
them
or
let
them
fall
into
the
relay
assembly
.
Carefully
place
the
settings
board
on
top
of
the
cradle
to
expose
the
This
voltage
is
rectified
and
filtered
before
being
applied
to
the
multiplexor
and
analog
-
to
-
digital
converter
,
which
are
internal
to
the
microprocessor
.
©
9
Courtesy of NationalSwitchgear.com

GEK
-
100682
communication
card
’
s
SIMM
socket
located
on
the
lowest
board
(
digital
input
/
communications
board
)
,
SET
THE
COMMUNICATIONS
ADDRESS
(
Figure
19
)
before
restoring
the cradle
to
the
case
.
f
4
.
To
expose
the
SIMM
socket
located
on
the
lowest
board
,
carefully
push
down
on
the
board
to
disengage
the
board
spacers
.
(
Figure
14
)
(
Do
not
try
to
remove
the board
from
the
cradle
.
)
MEASUREMENT
A
timer internal
to
the
microprocessor
generates
an
interrupt
every
millisecond
.
Phase
and
ground
measurements
are
made
at
each
of
these
interrupts
.
These
measurements
are
grouped
,
separately
for
each
phase
and
ground
,
in
groups
of
ten
,
and
the
average
of
the
maximum
value
of
these
groups
is
taken
.
Replacing
Existing
Board
4
a
.
For
Replacement
Only
( Skip
to
Step
5
if
installing
card
for
the
first time
)
.
Si
*
•
>
.
This
average
is
converted
to
"
times
pickup
TOC
"
,
which
is
the value
with
which
the
relay
works
.
This
value
is
displayed
in
5
second
intervals
.
If
you
are
replacing
an
existing
SIMM
card
,
then
the
old
one
needs
to
be
removed
!
Start
by
simultaneously
pushing
outwards the catches
on
either
side
of
the
SIMM
board
,
while
lifting
the
board
to
a
45
°
angle
.
This
will
release the board
.
INVERSE
TIME
UNO
'
Installing
New
Board
The
times
-
pickup
-
TOC
measurement
obtained is
compared
,
independently
for
each
phase
and
ground
,
with
a
value
,
the
pickup
setting
,
that
corresponds
to
one
times
(
lx
)
pickup
TOC
,
If
the
measurement
exceeds the fixed
setting
,
a
Pickup
LED
lights
on
the
front of
the
relay
,
Remove
the
communications
card
from
its
protective
packaging
.
Insert
the
card into
the
SIMM
socket
at
a
45
°
angle
to
the
socket with the
integrated
circuits
facing
up
,
Push
the
card
down
until
it
snaps
into
the socket and
the
latches
on
either side
of
the
board
catch
above
the
new
board
(
Figure
16
)
.
r
;
*
6
,
Re
-
assemble
the
MDP
relay by engaging
the
board
spacers
of
the
lowest
board
(
digital
input
/
communications
board
)
into
the
processor
board above
it
.
(
Figure
18
)
Align
the
NOMEX
shield
on
the
solder side
of
the
settings
board
.
Take
one screw
and
spacer
at
a
time
and
push
the
screw
through
the
nameplate
,
spacer
,
settings
board
and
NOMEX
.
5
.
f
The minimum
current
necessary
to
cause
the
Inverse
Time
measuring
elements
to
operate
is
never
less
than
the
set
value
(
Is
)
,
nor
greater
than
10
%
more
than
(
110
%
of
)
the
set
value
.
1.0
Is
<
Imin
<
1.1
Is
The
dropout
-
to
-
pickup
ratio
is
not
less
than
95
%
,
based
on
the
actual
operating
value
.
The
MDP
relay
incorporates
five
inverse
time
curves
and
four
definite
times
(
see
Figures
1
to
5
)
,
NOTE
i
The
NOMEX
protects
the
ribbon
cable
from
the
leads
on
the
settings
board
.
The
curve
within
a
family
is
selected
by
the
time
dial
.
The
characteristic
curves
for
the
MDP
relay
correspond
approximately
to
the
following
formulae
:
Tighten the
screw
just
enough
to
hold
the
assembly
in
place
until
all
four
screws
are
aligned
.
When
all
the
screws
are
aligned
,
tighten
them
with
gentle
pressure
so
that
the
board
is
mounted
evenly
.
10
Courtesy of NationalSwitchgear.com