Doc.

N° MO-0048-ING

MICROELETTRICA SCIENTIFICA
MILANO ITALY MD32-G Rev. 1
Pag. 1 of 22

DIGITAL-MULTIFUNCTION
GENERATOR DIFFERENTIAL
PROTECTION RELAY
TYPE MD32-G

OPERATION MANUAL

Copyright 1997 Microelettrica Scientifica

1 MOD. N°426 17-07-97 P.Brasca D.Abad

0 EMISSION 23-01-97 P.Brasca D.Abad
REV. DESCRIPTION DATE PREP. CONTR. APPR.
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MICROELETTRICA SCIENTIFICA
MILANO ITALY MD32-G Rev. 1
Pag. 2 di 22

INDEX
1 General utilization and commissioning directions.............................................................. 3
1.1 Storage and transportation................................................................................................3
1.2 Installation........................................................................................................................3
1.3 Electrical connection........................................................................................................ 3
1.4 Measuring inputs and power supply................................................................................. 3
1.5 Outputs loading................................................................................................................ 3
1.6 Protection earthing........................................................................................................... 3
1.7 Setting and calibration..................................................................................................... 3
1.8 Safety protection.............................................................................................................. 3
1.9 Handling...........................................................................................................................3
1.10 Maintenance.....................................................................................................................4
1.11 Fault detection and repair................................................................................................. 4
2 General characteristics and operation................................................................................. 4
2.1 Power supply.................................................................................................................... 4
2.2 Differential protection F87TG.......................................................................................... 5
2.3 Stator Overcurrent Protection F51G................................................................................. 6
2.4 Breaker Failure Protection................................................................................................6
2.5 Earth Fault protection F87N/F51G................................................................................... 7
2.6 Functions blocking........................................................................................................... 7
2.7 Characteristics required for C.Ts. ................................................................................... 8
2.8 Value of the stabilising resistor....................................................................................... 8
3 Controls and measurements.................................................................................................. 9
4 Signalization........................................................................................................................... 10
5 Output relays.......................................................................................................................... 10
6 Serial communication............................................................................................................ 11
7 Oscillography records........................................................................................................... 11
8 Digital inputs.......................................................................................................................... 11
9 Test.......................................................................................................................................... 11
10 Keyboard and display operation.......................................................................................... 12
11 Reading of measurements and recorded parameters......................................................... 12
ACT. MEAS (Actual measure)........................................................................... 12
MAX VAL (Max val)..................................................................................…... 13
LASTTRIP (Last trip)....................................................................................... 13
TRIP NUM (Trip number)................................................................................ 13
12 Reading of programmed settings and relay’s configuration.............................................. 14
13 Programming.......................................................................................................................... 14
13.1 Programming of functions settings.......................................................................... 14
13.2 Programming the configuration of output relay...................................................... 15
14 Manual and automatic test operation................................................................................... 16
15 Maintenance............................................................................................................................16
16 Electrical characteristics........................................................................................................ 17
17 Connection diagram............................................................................................................... 18
87G + 87N.............................................................................................................. 18
87G + 64G.............................................................................................................. 18
18 Wiring the serial communication bus................................................................................... 19
19 Direction for pcb’s draw-out and plug-in............................................................................ 20
20 Overall dimensions................................................................................................................ 20
21 Keyboard operational diagram............................................................................................ 21
22 Setting’s form......................................................................................................................... 22
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MILANO ITALY MD32-G Rev. 1
Pag. 3 of 22

1. GENERAL UTILIZATION AND COMMISSIONING DIRECTIONS

Always make reference to the specific description of the product and to the
Manufacturer's instruction.
Carefully observe the following warnings.
1.1 - STORAGE AND TRANSPORTATION,
must comply with the environmental conditions stated on the product's instruction or by the
applicable IEC standards.
1.2 − INSTALLATION,
must be properly made and in compliance with the operational ambient conditions stated by
the Manufacturer.
1.3 - ELECTRICAL CONNECTION,
must be made strictly according to the wiring diagram supplied with the Product, to its electrical
characteristics and in compliance with the applicable standards particularly with reference to
human safety.
1.4 − MEASURING INPUTS AND POWER SUPPLY,
carefully check that the value of input quantities and power supply voltage are proper and within
the permissible variation limits.
1.5 − OUTPUTS LOADING,
must be compatible with their declared performance.
1.6 − PROTECTION EARTHING
When earthing is required, carefully check its efficiency.
1.7 − SETTING AND CALIBRATION
Carefully check the proper setting of the different functions according to the configuration of the
protected system, the safety regulations and the co-ordination with other equipment.
1.8 - SAFETY PROTECTION
Carefully check that all safety means are correctly mounted, apply proper seals where
required and periodically check their integrity.
1.9 − HANDLING
Notwithstanding the highest practicable protection means used in designing M.S. electronic
circuits, the electronic components and semiconductor devices mounted on the modules can be
seriously damaged by electrostatic voltage discharge which can be experienced when handling
the modules.
The damage caused by electrostatic discharge may not be immediately apparent but the design
reliability and the long life of the product will have been reduced. The electronic circuits produced
by M.S. are completely safe from electrostatic discharge (15 KV IEC 255.22.2) when housed in
their case; withdrawing the modules without proper cautions expose them to the risk of damage.
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MILANO ITALY MD32-G Rev. 1
Pag. 4 of 22

a. Before removing a module, ensure that you are at the same electrostatic potential as
the equipment by touching the case.
b. Handle the module by its front-plate, frame, or edges of the printed circuit board.
Avoid touching the electronic components, printed circuit tracks or connectors.
c. Do not pass the module to any person without first ensuring that you are both at the
same electrostatic potential. Shaking hands achieves equipotential.
d. Place the module on an antistatic surface, or on a conducting surface which is at the
same potential as yourself.
e. Store or transport the module in a conductive bag.
More information on safe working procedures for all electronic equipment can be found
in BS5783 and IEC 147-OF.
1.10 − MAINTENANCE
Make reference to the instruction manual of the Manufacturer ;
maintenance must be carried-out by specially trained people and in strict conformity
with the safety regulations.
1.11 − FAULT DETECTION AND REPAIR
Internal calibrations and components should not be alterated or replaced.
For repair please ask the Manufacturer or its authorised Dealers.
Misapplication of the above warnings and instruction relieves the Manufacturer of any liability.

2. GENERAL CHARACTERISTICS AND OPERATION 5Amp.

Input currents from system’s CT.s are supplied to two internal Dip-switch
sets of 3 CT.s 5Amp. 1Amp.
An additional CT is used either for Restricted Earth Fault 1A 8
protection or for Stator Earth Fault current protection 1B 7
6
1C
(see connection diagrams). 2A 5
4 1
2B
Input rated current can be set to 1 of 5A by 7 dip-switches 2C 3
Io 2
provided on relay’s card. 1

1Amp.

2.1- POWER SUPPLY

The auxiliary power is supplied by a built-in interchangeable module fully isolated an self
protected. Two options are available :
 24V(-20%) / 110V(+15%) a.c.  80V(-20%) / 220V(+15%) a.c.
a) -  b) - 
 24V(-20%) / 125V(+20%) d.c.  90V(-20%) / 250V(+20%) d.c.
Before energising the unit check that supply voltage is within the allowed limits.
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MILANO ITALY MD32-G Rev. 1
Pag. 5 of 22

2.2 - Differential Protection F87G

The relay performs a percentage biased differential protection of generator or rotating machinary:
- Two or three phase internal faults
- Interturn faults
- Earth Fault in low-impedance or directly earthed generators.
For each phase the relay measures :
- The R.M.S. value of the Vector Difference between side 1 currents
− −
d x =I 1x − I 2x x = A, B, C
− −
I 1+I 2
- The Generator’s “Through current” Ir = (per unit of rated relay’s input current In)
2
The operation is based on the above measurements and on the following programmable levels :
- Basic minimum differential pick-up level : d> = (0.02 - 0.2)In, step 0.01In
IR
- Percent bias in the zone 0.5 < <P : 1R% = (2-20)%, step 1%
In
IR
- Percent bias in the zone >P : 2R% = (5-50)%, step 1%
In
- Point of bias slope changement : P = (1.00 - 3.00)
To compensate differential current produced by errors of the CT the actual differential current
minimum pick-up level Is is dynamically adjusted in function of the actual Through Current Ir
depending on the set percent bias levels 1R%, 2R%.
Fig.1

Is/In 4 ∆I d ∆(I1 - I 2 )
R% = 100 = 100
8
∆I R ∆(I1 + I 2 ) : 2

Is I d
0,2
3 • =
∆lR ∆ld In In
∆lR
Is I d I 1R%
0,1
2 ‚ = + ( R − 0,5) ⋅
In In In 100
∆ld
1
Is I d (P - 0,5)1R% I R
ld/In
2R%
ƒ = + + ( − P)
0 IR/In In In 100 In 100
0,5 1 2 P 3
Is= Effective relay’s operation differential current
Id= Relay’s setting differential current „ Is
≅8
In

The low set differential element operates instantaneously (less than 30ms) when the measured
differential current Idx of any phase is above the pick-up level Is,
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2.3- Stator Overcurrent Protection F51G

Relays measures the R.M.S. value of the phase currents.

- Minimum pick-up level : I> = (0.5-10)In, step 0.01In
- Trip time delay (Independent Definite time) : tI> = (0.05-9.99)s, step 0.01s

2.4- Breaker Failure Protection

- tBF = (0.05-1.00)s, step 0.01s

If after the time tBF from tripping of one function the tripping cause (d>, I>, Io>) is not removed,
a proper output relay is energized to operate the second opening circuit of the Circuit Breaker
or a back-up breaker.
It is possible to select which protection element controls the Breaker Failure function by
programming the variable:

- BF = d, I, do

any combination is possible

BF = d - -
BF = - I -
BF = - - do
BF = d I -
BF = d - do
BF = d I do
BF = - I do
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MILANO ITALY MD32-G Rev. 1
Pag. 7 of 22

2.5- Earth Fault protection F87N/F51G

The relays measures the fundamental component only of the current feeding the input
terminals 32-33
Depending upon connection this element can perform:

- Restricted Earth Fault Protection

- Neutral current protection (stator earth fault).

The adjustable parameters are :

- Minimum pick-up level : do> = (0.01 - 1)Ion, step 0.01

(Ion = Rated current of CT feeding input terminals 32-33)

- Instantaneous element : t ≤ 30ms

- Time delayed element : tdo = (0.05 - 9.99)s, step 0.01

(trip level do> same as instantaneous element Definite time)

2.6 - Functions Blocking

Any function can be permanently disactivated setting to Dis the relevant variable, or temporarily
blocked via the digital input B1
The operation of the blocking input B1 can be programmed to block (when activated) any of the
relay functions by programming the variable B

- B = d>, I>, Io

any combination is possible :

B= d> - -
B= - I> -
B= - - Io
B= d> I> -
B= d> - Io
B= d> I> Io
B= - I> Io
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Pag. 8 of 22

2.7 - CHARACTERISTICS REQUIRED FOR C.Ts.

Relay burden on inputs at rated current

Phase inputs : PB = 0.01VA for C.T. 1A; PB = 0.2VA for C.T. 5A

Neutral inputs : EB = 0.02VA for C.T. 1A; EB = 0.3VA for C.T. 5A

C.T.’s requirements for phase differential protection

- Class 5P10 (or better)

- Minimum burden 10xPB+(RCT+RL), where:
RCT = Resistance of C.T.’s secondary winding
RL = Resistance of the loop lead between C.T. and relay

Additional requirements for R.E.F. protection

- Minimum Knee-point voltage Vm = 2If(RCT+RL), where If is the maximum expected Earth

Fault current (C.T.’s secondary).
The effective minimum C.T.’s. secondary current that produces relay pick-up is:
domin = [do>] - 4Im, where:
[do>] = Relay setting current
Im = C.T. excitation current at Vm/2.
As a consequence to operate on a Fault Current Ido the relay setting current shall be
[do>] = Ido - 4Im

2.8 - VALUE OF THE STABILISING RESISTOR

- The value of the externally mounted series resistor R is calculated as follows:

Vm / 2 − EB / [do >]
R=
[do >]

Continuously variable resistors are normally used:

- for 1A C.T.: (0-200)Ohm 100W rated
- for 5A C.T.: (0-50)Ohm 100W rated

In the unlikely case where the maximum prospective current Iom during internal Earth Fault can
produce at C.T.’s terminals a voltage Vm = Iom(R+RTC+RL) >2kV a non linear voltage limiting
device Z is available
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MILANO ITALY MD32-G Rev. 1
Pag. 9 of 22

3. CONTROLS AND MEASUREMENTS

Five key buttons allow for local management of all relay's functions.
A 8-digit high brightness alphanumerical display shows the relevant readings (xxxxxxxx)
(see synoptic table fig.1)
FIG.1
MODE SELECT + - ENTER

ACT MEAS Actual measuremant values

MAX VAL Max. values measured

MEASURES Scanning of
Measurements LastTr-X Recording of last five events the menus by
display the key
TRIP NUM N° of tripping for each function “+” “-”
SETTINGS Display of setting
SET DISP
F→RELAY Display of configuration of output relay
Setting Program
display Paramater scanning
by the key
(*) PROG SELECT
SETTINGS Setting of parameters
PROGR Parameter modification
F→RELAY Configuration of output relays by the key “+” “-”
Set Programming
Set validation
by the key ENTER

W/O TRIP Test with operation of signals only

TEST PRG
WithTRIP Test activation
Functional Test
Test with operation of signals and output relays
by the key ENTER
(*)
(*) Enabled only if input current is zero
Pressing this button progressively
The + and - buttons are used to
selects between
select the actual measurement or
Measurements Display,
display desired when in
Setting Display, Programming,
Measurements Display or Settings
and Test modes
Display modes. When in Program
MODE SELECT
+ mode, these buttons increase or
The SELECT button chooses decrease the value of the
which category of values within displayed setting.
the chosen mode to display
PROG
-
When in Program mode, and
When in Program mode, this
when all input currents are zero,
button stores the newly selected ENTER/RESET
pressing this recessed button
value. If not in Program mode and
places the relay into active
the relay has tripped, this button
programming mode, allowing any
resets the relay and all output
or all of the relays settings to
contacts. If not tripped, this button
altered.
restores the default display.
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Pag. 10 of 22

4. SIGNALIZATIONS
Eight signal leds (normally off) provide the following information:

a) Red LED dA> : Illuminated on tripping of differential elements phase A (IdA≥[d>])

b) Red LED dB> : Illuminated on tripping of differential elements phase B (IdB≥[d>])
>
c) Red LED dC> : Illuminated on tripping of differential elements phase C ((IdC≥[d>])
>
d) Red LED d0> : Illuminated on tripping of the earth fault element (Io>[do>])
e) Yellow LED PROG/I.R.F. : Flashing during the programming of the parameters or in case of
Internal Relay Fault.
f) Red LED I> : Flashing when the current in any phase exceeds the set level [I>]
Illuminated on trip at the end of time delay tI>
g) Red LED B.F. : Illuminated on trip of the Breaker Failure function
h) Yellow LED BLOCK INPUT : Flashing when digital input B1 is activated
The reset of the leds takes place as follows:
-From flashing to off, automatically when the lit-on cause disappears.
-From ON to OFF, by "ENTER/RESET" push button only if the tripping cause has disappeared.
In case of auxiliary power supply failure the status of the leds is recorded and reproduced when power
supply is restored.
5. OUTPUT RELAYS
Five output relays are available (R1, R2, R3, R4, R5)
a) - The relays R1,R2,R3,R4 are normally deenergized (energized on trip): these output relays are user
programmable and any of them can be associated to any of the MD32's functions.
For function do> both instantaneous and time delayed elements are provided.
Any relay associated to of any function picks-up as soon as the measured input value gets into the
operation zone.
The reset after tripping of the relays (when tripping cause has been cleared) can be programmed as
Manual or Automatic (Variable RR=Man/Aut).
FRes = Aut : Automatic Reset as soon as pick-up cause has been cleared.
FRes = Man : Reset by ENT/RESET KEY on relay’s front or via serial port
It has to be remarked that the programming structure does not allow to associate the same relay both
to instantaneous and delayed elements. Therefore any relay already associated to any time delayed
element cannot be associated to any instantaneous element and viceversa.
b) - The relay R5, normally energised, is not programmable and is deenergized on:
- internal fault
- power supply failure
- during the programming
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Pag. 11 of 22

6. SERIAL COMMUNICATION (Optional: see relevant instruction manual)

The relays fitted with the serial communication option can be connected via a cable bus or
(with proper adapters) a fiber optic bus for interfacing with a Personal Computer
Via the communication bus all settings and commands available from relay's keyboard can be operated
from the computer and viceversa all information available at relay's level can be received at computer's
level. The transmission standard is RS485 (converter 485/232 available) with ModBus/Jbus protocol.
Each relay is identified by its programmable address code (NodeAd) and can be called from the P.C. fitted
with a WINDOWS (version 3.1 or later) program driven by an application program supplied by
Microelettrica Scientifica or made by the user.

7. OSCILLOGRAPHY RECORDS

The relay continuously records in a buffer the samples of the six input phase currents and the residual zero
sequence current.
The buffer contains samples for approximately 16 periods.
Recording is stopped after approximately 8 periods after a trigger signal and the content of the buffer is
stored into memory.
Therefore in the memory are stored the wave forms for 8 cycles before and 8 cycles after the trigger
instant.
The trigger can be operated either internally on tripping of any function programmed d>, I>, Io>, or
externally by activation of the digital input B3.
Selection between the two modes is made by programming the variable TRG = EXT, d>, I>, do>
The last two oscillography records are stored; a third record replaces the first of the two records.
8. DIGITAL INPUTS
Two inputs active when the relevant terminals are shorted are provided:
- B1 (terminals 1 - 2) : For function blocking
- B2 (terminals 1 - 3) : Not used
- B3 (terminals 1 - 14) : External trigger for oscillography records
9. TEST
Besides the normal "WATCHDOG" and "POWERFAIL" functions, a comprehensive program of self-test
and self-diagnostic provides:
- Diagnostic and functional test with checking of program routines and
memory's content, run every time the aux. power is switched-on:
the display shows the type of relay and its version number and then switches over
to the default display.
- Dynamic functional test run during normal operation every 10 minutes.
- Complete test activated by the keyboard or via the communication bus either
with or without tripping of the output relays.
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Pag. 12 of 22

10. KEYBOARD AND DISPLAY OPERATION

All controls can be operated from relay's front or via serial communication bus.
The keyboard includes five hand operable buttons (MODE)-(SELECT)-(+)-(-)-(ENTER/RESET)
plus one indirect operable key (PROG) (see synoptic table a fig.1):
a) - White key MODE: when operated it enters one of the following operation modes indicated on the
display:
MEASURE = Reading of all the parameters measured and of those recorded in the memory
SET DISP = Reading of the settings and of the configuration of the output relays as
programmed.
PROG = Access to the programming of the settings and of relay configuration.
TEST PROG = Access to the manual test routines.
b) - Green key SELECT : when operated it selects one of the menus available in the actual
operation MODE
c) - Red key"+" AND "-" : when operated they allow to scroll the different information
available in the menu entered by the key SELECT
d) - Yellow key ENTER/RESET : it allows the validation of the programmed settings
- the actuation of test programs - the forcing of the default
display indication - the reset of signal Leds.
e) - Indirect key PROG : enables access to the programming.

11. READING OF MEASUREMENTS AND RECORDED PARAMETERS

Enter the MODE "MEASURE", SELECT the menus "ACT.MEAS"-"MAX VAL"-"LASTTRIP"-

"TRIP NUM", scroll available information by key "+" or "-" .

ACT.MEAS = Actual values as measured during the normal operation.

The values displayed are continuously updated.

Display Description
dAxx.xxn R.M.S. value of differential current of phase A : (0-99.99) per unit of rated phase input
current
dBxx.xxn As above phase B
dCxx.xxn As above phase C
do x.xxn System frequency component of current Io :(0-9.99) per unit of rated phase input current
1AxxxxxA R.M.S. value of current of phase A of Generator’s side 1: (0-99999) CT’s primary Amp
1BxxxxxA As above phase B
1CxxxxxA As above phase C
2AxxxxxA R.M.S. value of current of phase A of Generator’s side 2: (0-99999) CT’s primary Amp
2BxxxxxA As above phase B
2CxxxxxA As above phase C
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MAX VAL = Highest values recorded from Breaker closing, (updated any time the breaker closes).

Display Description
dAxx.xxn Differential current of phase A : (0-99.99) per unit of rated phase input current
dBxx.xxn As above phase B
dCxx.xxn As above phase C
dox.xxxn System frequency component of current Io : (0-9.99) p.u. of rated phase input current
1Axx.xn Current of phase A of Generator’s side 1: (0-99.9) p.u. of phase input current
1Bxx.xn As above phase B
1Cxx.xn As above phase C
2Axx.xn Current of phase A of Generator’s side 2: (0-99.9) p.u. of phase input current
2Bxx.xn As above phase B
2Cxx.xn As above phase C

LASTTRIP = Display of the function which caused the tripping of the relay plus values of the
parameters at the moment of tripping. The memory buffer is refreshed at each new
relay tripping.

Display Description
LastTr-x Indication of the recorded event (x= 0 to 4)
Example: Last event (LastTr -0)
Last but one event (LastTr-1) etc...
Cau:xxxx Function which produced the event being displayed: dA>, dB>, dC>, I>, do>
dAxx.xxn Differential current phase A
dBxx.xxn Differential current phase B
dCxx.xxn Differential current phase C
dox.xxn Residual current Io
1Axxxxn Current phase A of Generator’s side 1
1Bxxxxn As above phase B
1Cxxxxn As above phase C
2Axx.xn Current of phase A of Generator’s side 2: (0-99.9) p.u. of phase input current
2Bxx.xn As above phase B
2Cxx.xn As above phase C

TRIP NUM = Counters of the number of operations for each of the relay’s function.
The memory is non-volatile and can be cancelled only with a secret procedure.

Display Description
dA> xxxx Differential element phase A
dB> xxxx Differential element phase B
dC> xxxx Differential element phase C
do> xxxx Earth fault element
I> xxxx Overcurrent element
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Pag. 14 of 22

12. READING OF PROGRAMMED SETTINGS AND RELAY'S CONFIGURATION

Enter the mode "SET DISP", select the menu "SETTINGS" or "F → RELAY", scroll information available
in the menu by keys "+" or "-".
SETTINGS= values of relay's operation parameters as programmed
F → RELAY= output relays associated to the different functions as programmed.

13. PROGRAMMING
The relay is supplied with the standard default programming used for factory test. [ Values here below
reported ( ----- ) ].
All parameters can be modified as needed in the mode PROG and displayed in the mode SET DISP
Programming is enabled only if no input current is detected (main circuit breakers open).
As soon as programming is enabled, the Led PRG/IRF flashes and the reclosing lock-out relay R5 is
deenergized. Enter MODE "PROG" and SELECT either "SETTINGS" for programming of parameters
or "F→RELAY" for programming of output relays configuration; enable programming by the indirect
operation key PROG.
The key SELECT now scrolls the available parameters. By the key (+) , (-) the displayed values can be
modified; to speed up parameter's variation press the key SELECT while "+" or "-" are pressed.
Press key "ENTER/RESET" to validate the set values.
13.1 - PROGRAMMING OF FUNCTIONS SETTINGS

In 500 Ap

1In is the name 500 is the Ap is the unit of measure,

of the variable setting default Amps primary.

Mode PROG menu SETTINGS. (Production standard settings here under shown).

Display Description Setting Range Step Units

Fn 50 Hz System frequency 50 - 60 10 Hz
In 500A Rated primary current of CTs 1 - 9999 1 A
d> 0.15n Basic minimum pick-up level of low set phase differential element 0.02-0.2-Dis 0.01 In
1R 2% Bias percentage in the zone 0,5<IR<P 2-20 1 %
2R 20% Bias percentage in the zone IR>P 5-50 1 %
P 2.50 Bias slope change point 1.00-3.00 0.01 -
I>5.00In Minimum pick-up level of overcurrent element 0.50-8 0.01 In
tI>3.00s Time delay of overcurrent element 0.05-9.99 0.01 s
do> .10n Minimum pick-up level of Earth Fault element 0.01-1-Dis 0.01 In
tdo5.00s Time delay of Earth Fault element 0.05-9.99 0.01 s
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Display Description Setting Range Step Units

BF I Selection of element controlling the Breaker Failure function d - I - do any combination

tBF 0.25s Breaker Failure time delay 0.05-1.00 0.01 s

B1 do Digital input B1 blocks the function selected d - I - do any combination

TRG Ext Trigger for oscillography records is Internal or External Ext, d>, I>, do> -
(via digital input B3)
NodAd 1 Identification number for connection on serial communication bus 1 - 250 1 -

The setting Dis indicates that the function is disactivated.

13.2 - PROGRAMMING THE CONFIGURATION OF OUTPUT RELAYS

d> - 2 - 4

This is the name of This dash means that The number 2 This dash means The number 4 means
protective element output relay number means that output that output relay that output relay 4 will
1 is not assigned to relay 2 will number 3 is not operate when this
this element operate when this assigned to this element trips
element trips element

Mode PROG menu F→RELAY (Production standard settings here under shown).
The key "+" operates as cursor; it moves through the numbers corresponding to the four programmable
relays in the sequence 1,2,3,4,(1= relay R1, etc.) and makes start flashing the information actually present
in the digit. The information present in the digit can be either the number of the relay (if this was already
associated to the function actually on programming) or a dot (-) if the relay was not yet addressed.
The key "-" changes the existing status from the dot to the relay number or viceversa.
After having programmed all the four relay, press “ ENTER “ to validate the programmed
configuration.
Display Description
d> 1--- Differential element operates relay R1, R2, R3, R4 as programmed (one or more)
I> ---- Instantaneous Overcurrent element operates relay R1, R2, R3, R4 as programmed
tI> --3- Time delayed Overcurrent element operates relay R1, R2, R3, R4 as programmed
do> -2-- Instantaneous Earth Fault element operates relay R1, R2, R3, R4 as programmed
tdo --3- Time delayed Earth Fault element relay R1, R2, R3, R4 as programmed
tBF ---4 Breaker Failure function relay R1, R2, R3, R4 as programmed
FRes: Aut. Reset of output relays after tripping is:
Aut. = Automatic Man. = Manually key Enter /Reset or via serial bus
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MILANO ITALY MD32-G Rev. 1
Pag. 16 of 22

14. MANUAL AND AUTOMATIC TEST OPERATION

- Mode "TESTPROG" subprogram “W/O TRIP":

Operation of the yellow key activates a complete test of the electronics and the process routines.
All the leds are lit-on and the display shows (TEST RUN). If the test routine is successfully completed
the display switches-over to the default reading (dAxx.xxn). If an internal fault is detected, the display
shows the fault identification code and the relay R5 is deenergized. This test can be carried-out even
during the operation of the relay without affecting the relay tripping in case a fault takes place during
the test itself.

- Mode "TESTPROG" subprogram "WithTRIP":

Access to this program is enabled only if the current detected is zero (breaker open).
Pressing the yellow key the display shows "TEST RUN?". A second operation of the yellow key starts
a complete test which also includes the activation of all the output relays. The display shows
(TEST RUN) with the same procedure as for the test with W/O TRIP. During the normal operation the
relay continuously operates an auto test procedure. If any internal fault is detected during the auto test,
the relay R5 is deenergized, the relevant led is activated and the fault code is displayed. If at the next
automatic test no internal fault is detected the display and R5 reset.

- Further operation of key SELECT instead of the TEST programs gives the indication of the version and
production date of the firmware.

CAUTION
Running the WithTRIP test will operate all of the output relays. Care must be taken to ensure that no
unexpected or harmful equipment operations will occur as a result of running this test.
It is generally recommended that this test be run only in a bench test environment or after all dangerous
output connections are removed.

15. MAINTENANCE

No maintenance is required. Periodically a functional check-out can be made with the test procedures
described under MANUAL TEST chapter. In case of malfunctioning please contact Microelettrica
Scientifica Service or the local Authorised Dealer mentioning the relay's Serial No reported in the label on
relays enclosure.

WARNING
In case of Internal Relay Fault detection, proceed as here-below indicated :
Ø If the error message displayed is one of the following “DSP Err”, “ALU Err” ,”KBD Err” ,”ADC
Err”, switch off power supply and switch-on again. If the message does not disappear send the relay to
Microelettrica Scientifica (or its local dealer) for repair.
Ø If the error message displayed is “E2P Err” , send the relay to Microelettrica Scientifica (or its local
dealer) for repair.
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MILANO ITALY MD32-G Rev. 1
Pag. 17 of 22

16. ELECTRICAL CHARACTERISTICS

- Reference standards IEC 255, IEC1000; IEEE C37; CE Directive

- Dielectric test voltage IEC 255-5 : 2kV, 1 min.
- Impulse test voltage IEC 255-5 : 5kV (c.m.), 2 kV (d.m.) - 1,2/50µs
- HF disturbance test with damped
oscillatory wave (1MHz burst test) IEC255-22-1 class 3 : 2,5kV (m.c.), 1kV (d.m.)
- Electrostatic discharge test IEC1000-4-2 level 4 : 15 kV
- Conducted disturbances immunity test IEC1000-4-6 level 3 : 0.15-80MHz, 10V/m
- Radiated electromagnetic field immunity test IEC1000-4-3 level 3 : 80-1000MHz, 10V/m
- Electrical fast transient/burst IEC1000-4-4 level 4 : 4kV, 2.5kHz, 15/300ms (c.m.)
2kV, 5kHz, 15/300ms (d.m.)
- Surge immunity test IEC1000-4-5 level 4 : 4kV(c.m.), 2kV(d.m.)
- Oscillatory waves (Ring waves) IEC1000-4-12 level 4 : 4kV(c.m.), 2kV(d.m.)
- Power frequency magnetic test IEC1000-4-8 : 1000A/m
- Pulse magnetic field IEC1000-4-9 : 1000A/m, 8/20µs
- Damped oscillatory magnetic field IEC1000-4-10 : 1000A/m, 0.1-1MHz
- Immunity test for voltage dips,
short interruptions and voltage variations IEC1000-4-11
- HF inducted voltage IEC1000-4-1 A.2.6 level 4 : 100V, 0.01-1MHz
CE EMC Compatibility:
- Electromagnetic emission EN50081-2
- Radiated electromagnetic disturbance test EN50082-2
- Resistance to vibration and shocks IEC255-21-1, IEC255-21-2
- Accuracy at reference value of 1% In; 0,1% On for measure
influencing factors +/- 10ms for times
- Rated input current In = 1 or 5A, On = 1 or 5A
- Current overload 200A for 1 sec; 10A continuos
- Burden on current inputs Phase : 0.01VA at In = 1A; 0.2VA at In = 5A
Neutral : 0.015VA at On = 1A; 0.35VA at On = 5A
- Average power supply consumption 8,5 VA
- Output relays rating 5 A; Vn = 380 V
A.C. resistive switching = 1100W (380V max)
make = 30 A (peak) 0,5 sec.
break = 0.3 A, 110 Vcc,
L/R = 40 ms (100.000 op.)
- Operation ambient temperature -20°C / +60°C
- Storage temperature -30°C / +80°C

Microelettrica Scientifica S.p.A. - 20089 Rozzano (MI) - Italy - Via Alberelle, 56/68
Tel. (##39) 2 575731 - Fax (##39) 2 57510940 - Telex 351265 MIELIT I
http://www.microelettrica.com
The performances and the characteristics reported in this manual are not binding and can modified at any moment without notice
 Doc. N° MO-0048-ING

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MILANO ITALY MD32-G Rev. 1
Pag. 18 of 22

17. CONNECTION DIAGRAM (SCE1492 Rev.0)

(SCE1493 Rev.0)
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Pag. 19 of 22

18. WIRING THE SERIAL COMMUNICATION BUS (SCE1309 Rev.0)

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MILANO ITALY MD32-G Rev. 1
Pag. 20 of 22

19. DIRECTION FOR PCB'S DRAW-OUT AND PLUG-IN

DRAW-OUT
Rotate clockwise the screws • and ‚ in the horizontal position of the screws-driver mark.
Draw-out the PCB by pulling on the handle ƒ
PLUG-IN
Rotate clockwise the screws • and ‚in the horizontal position of the screws-driver mark.
Slide-in the card on the rails provided inside the enclosure.
Plug-in the card completely and by pressing the handle to the closed position.
Rotate anticlockwise the screws • and ‚ with the mark in the vertical position (locked).

20. OVERALL DIMENSIONS

PANEL DRILLING 113x142 (LxH)

 MODE MILANO

I=0 I≠0
ITALY

(MEASURES) (SETDISP) (PROGR) (TESTPROG)

In programming mode
SEL
MICROELETTRICA SCIENTIFICA

SEL SEL the output relay R5 SEL

is deenergized

MEAS) (MAX VAL) (LastTrip) (TRIPNUM)

(LastTrip-1) (SETTING1) (F→RELAY) (SETTING1) (F→RELAY) MD32-G
(LastTrip-2) I=0 I≠0 (Ver.:x.xx)
(LastTrip-3) PRG (SelPrg) PRG
+/- +/- (Dtxxxxxx)
(LastTrip-4) (EntPrS) (EntPrS)
0 Fn xx Hz 0 d> xxxx (W/O TRIP) (WithTRIP)
SEL ENT SEL ENT
/- +/- +/- +/- 1 InxxxxA 1 I> xxxx (UpDwnS) (UpDwnS)
dAxx.xxn dAxx.xxn Cau:xxxx dA> xxxx 2 d> xxxxn 2 tI> xxxx +/- +/- ENT ENT
0 0 0
dBxx.xxn dBxx.xxn dAxx.xxn dB> xxxx 3 1R xx% 3 do> xxxx
1 1 1
21. KEYBOARD OPERATIONAL DIAGRAM

dCxx.xxn dCxx.xxn dBxx.xxn dC> xxxx 4 2R xx% 4 tdo xxxx 0 Fn xx Hz 0 d> xxxx TESTRUN?
2 2 2
do x.xxn do x.xxn dCxx.xxn do> xxxx 5 P xxxx 5 tBF xxxx 1 InxxxxA 1 I> xxxx
3 3 3 ENT
6 I>xxxxIn 6 FResxxx 2 d> xxxxn 2 tI> xxxx
1AxxxxxA 4 1Axxxxxn 4 do x.xxn 4 I> xxxx
x
1BxxxxxA 1Bxxxxxn 1Axxxxxn 7 tI>xxxxs 3 1R xx% 3 do> xxxx
5 5 TEST RUN TEST RUN
1CxxxxxA 1Cxxxxxn 1Bxxxxxn 8 do>xxxxn 4 2R xx% 4 tdo xxxx
6 6
MD32-G

2AxxxxxA 2Axxxxxn 1Cxxxxxn 9 tdoxxxxs 5 P xxxx 5 tBF xxxx

7 7 1 msgFAULT 1 msgFAULT
2BxxxxxA 2Bxxxxxn 2Axxxxxn 10 BFxxxxxx 6 I>xxxxIn 6 FResxxxx
8 8 2 dAxx.xxn 2 dAxx.xxn
2CxxxxxA 2Cxxxxxn 2Bxxxxxn 11 tBF xxxxs 7 tI>xxxxs
9 9
2Cxxxxxn 12 B1xxxxxx 8 do>xxxxn
10
13 TRG: xxx 9 tdoxxxxs

14 NodAdxxx 10 BFxxxxxx

11 tBF xxxxs

12 B1xxxxxx

13 TRG: xxx

14 NodAdxxx
Pag.
Rev.
1
21 of
22
Doc. N° MO-0048-ING
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MILANO ITALY MD32-G Rev. 1
Pag. 22 of 22

22. SETTING’S FORM

Date : Number Relay:

RELAY PROGRAMMING
Default Setting Actual Setting
Variable Value Measurement Unit Variable Value Measurement Unit
Fn 50 Hz Fn Hz
In 500 A In A
d> 0.15 n d> n
1R 1 % 1R %
2R 20 % 2R %
P 2,5 ------------ P ------------
I> 5 In I> In
tI> 3 s tI> s
do> .10 n do> n
tdo 50 s tdo s
BF I ------------ BF ------------
tBF 0.25 ------------ tBF ------------
B1 do ------------ B1 ------------
TRG Ext ------------ TRG ------------
NodAd 1 ------------ NodAd ------------
CONFIGURATION OF OUTPUT RELAYS
Default Setting Actual Setting
Protective Elem. Output Relays Protective Elem. Output Relays
d> 1 - - - d>
I> - - - - I>
tI> - - 3 - tI>
do> - 2 - - do>
tdo - - 3 - tdo
tBF - - - 4 tBF
FRes: Aut. FRes: