Woodward MRIK3-C User manual

MRIK3-C
Digital time overcurrent relay with Control
function and auto reclosing
Manual MRIK3-C (RevisionA)

Woodward Manual MRIK3-C EN
2 DOK-TD-MRIK3-C Rev. A
Woodward Governor Company reserves the right to update any portion of this publication at any time. Information
provided by Woodward Governor Company is believed to be correct and reliable. However, no responsibility is as-
sumed by Woodward Governor Company unless otherwise expressly undertaken.
© Woodward

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 3
Contents
1.Comments on the manual...........................................................................7
1.1Information Concerning Liability and Warranty ...................................................................7
1.2IMPORTANT DEFINITIONS ...............................................................................................8
1.3How to use this instruction ..................................................................................................8
1.4Electrostatic Discharge Awareness.....................................................................................9
2.Introduction and Application....................................................................10
3.Characteristics and Features....................................................................10
4.Design.........................................................................................................11
4.1Connections ......................................................................................................................11
4.1.1Analog input circuits ......................................................................................................13
4.1.2Output relays .................................................................................................................13
4.1.3Digital inputs..................................................................................................................13
4.1.4Low/High range of the digital Inputs..............................................................................14
4.2Password...........................................................................................................................15
4.2.1Code jumpers ................................................................................................................15
4.2.2Password programming ................................................................................................15
4.3Front plate (for –ICE relay type)........................................................................................16
4.3.1Indicating LEDs .............................................................................................................16
4.3.2Adjusting LEDs..............................................................................................................16
4.4Front plates (for -ER/-XR-relay types) ..............................................................................17
4.4.1Indicating LEDs .............................................................................................................17
4.4.2Adjusting LEDs..............................................................................................................17
5.Working principle.......................................................................................18
5.1Analogue circuits...............................................................................................................18
5.2Digital circuits ....................................................................................................................18
5.3Status descriptions............................................................................................................18
5.3.1„Inactive“........................................................................................................................18
5.3.2„Reclaim time“ tR...........................................................................................................18
5.3.3„AR-ready“.....................................................................................................................19
5.3.4„AR-starting“ (dead time)...............................................................................................19
5.3.5„AR-cycle“ (auto reclosing)............................................................................................19
5.3.6„AR-blocked“ .................................................................................................................19
5.3.7„Fast Trip Mode“............................................................................................................19
5.3.8„Blocking mode“ ............................................................................................................19
5.3.9„Activating of AR“ ..........................................................................................................19
5.3.10Description of the status transition............................................................................20
5.3.11AR information inputs................................................................................................20
5.4Functional sequence .........................................................................................................21
5.4.1Switching on MRIK3-C ..................................................................................................21
5.4.2Circuit breaker manual closing......................................................................................21
5.4.3Circuit breaker manual open .........................................................................................21
5.4.4Starting AR ....................................................................................................................21
5.4.5Unsuccessful reclosing .................................................................................................22
5.4.6Successful reclosing .....................................................................................................22
5.4.7Repeated reclosing .......................................................................................................22
5.4.8Supervision of the circuit breaker ready information.....................................................23
5.4.9External blocking...........................................................................................................23
5.4.10Time sequence diagrams of MRIK3-C......................................................................23
5.4.11The unit is programmed for two shots, successful AR at the second shot ...............23
5.4.12The unit is programmed for two shots, unsuccessful AR..........................................24
5.4.13Manual closing of the circuit breaker to faulty lines ..................................................24
5.4.14Unsuccessful AR .......................................................................................................25
5.5Earth fault protection .........................................................................................................26
5.5.1Generator stator earth fault protection .........................................................................26
5.5.2System earth fault protection ........................................................................................26
5.6Earth-fault directional feature (ER/XR-relay type).............................................................27
5.7Control functions ...............................................................................................................29

Woodward Manual MRIK3-C EN
4 DOK-TD-MRIK3-C Rev. A
5.7.1Introduction ................................................................................................................... 29
5.7.2Interlocking / Password for control mode ..................................................................... 29
5.7.3Operating assignment of C.B. control........................................................................... 29
5.7.4Changing the operating assignment............................................................................. 29
5.7.5Saving the operating assignment ................................................................................. 30
5.7.6Remote switching on and off of the C.B. ...................................................................... 30
5.7.7Switching on or off the C.B. via the front panel (LCAL)................................................ 30
5.7.8Handling of the control function .................................................................................... 31
5.7.9Display for the control functions ................................................................................... 33
5.7.10LED-indication under normal mode .......................................................................... 34
5.7.11LED-indication auto reclosing conditions (AR) ......................................................... 35
5.8Requirement on the Main Current Transformers.............................................................. 36
6.Operation and Adjustments......................................................................37
6.1Displayed text for parameter settings ............................................................................... 37
6.2Setting procedure ............................................................................................................. 38
6.3Parameter levels............................................................................................................... 39
6.4System parameters........................................................................................................... 40
6.4.1Presentation of Measuring Values as Primary Quantities on the Display (Iprim Phase)
40
6.4.2Display of residual voltage UE as primary quantity (Uprim/Usec)................................ 40
6.4.3Voltage transformer connection for residual voltage measuring (3pha/e-n/1:1) ........ 40
6.4.4Operation cycle counter................................................................................................ 40
6.4.5I2*t Operation cycle counter ......................................................................................... 41
6.4.6Rated -Frequency ......................................................................................................... 41
6.4.7Indication of pickup ....................................................................................................... 41
6.4.8Parameter Set Changeover Switch (P2) ...................................................................... 41
6.5Protection Parameters ...................................................................................................... 42
6.5.1Pickup current for phase Overcurrent element............................................................. 42
6.5.2Trip Characteristics for the Phase Overcurrent Element (I>) ....................................... 42
6.5.3Tripping Time or Time Factor for the Phase Overcurrent Element .............................. 42
6.5.4Fast/Time tripping by switch ON of the CB for the overcurrent element ..................... 43
6.5.5Reset Mode for the Trip Characteristics in Phase Current Path ................................. 43
6.5.6Current setting for high set element ............................................................................. 43
6.5.7Trip-Block for all protection elements ........................................................................... 43
6.5.8Trip delay for high set element ..................................................................................... 43
6.5.9Fast/Time tripping by switch ON of the CB for the short circuit element.................... 44
6.5.10Pickup value for residual voltage (UE) (ER/XR-relay types) .................................... 44
6.5.11Pickup current for earth fault element (IE>).............................................................. 44
6.5.12WARN/TRIP changeover.......................................................................................... 44
6.5.13Time current characteristics for earth fault element (for E/X-relay types) ............... 44
6.5.14Tripping Time or Time Factor for the Earth Fault Element ....................................... 44
6.5.15Fast/Time tripping by switch ON of the CB for the earth fault low set element ....... 44
6.5.16Reset mode for inverse time tripping in earth current path ...................................... 45
6.5.17Current setting for high set element of earth fault supervision (IE>>)..................... 45
6.5.18Trip delay for high set element of earth fault supervision......................................... 45
6.5.19Fast/Time tripping by switch ON of the CB for the earth fault high set element...... 45
6.5.20COS/SIN Measurement (ER/XR-relay type)............................................................. 45
6.6AR Parameter ................................................................................................................... 45
6.6.1Number of AR shots ..................................................................................................... 45
6.6.2Fault time (tF) ............................................................................................................... 45
6.6.3Dead time (tD) .............................................................................................................. 45
6.6.4Close impulse time (tCI) ............................................................................................... 46
6.6.5Reclaim time (tR) .......................................................................................................... 46
6.6.6Fault time activation...................................................................................................... 46
6.7Control functions............................................................................................................... 47
6.7.1Block/Trip-time.............................................................................................................. 47
6.7.2Time delay for ext. Trip ................................................................................................. 47
6.7.3Dead time for Trip/Restore ........................................................................................... 47
6.7.4CB failure protection ..................................................................................................... 48
6.7.5Release of the pickup relay for CB failure protection ................................................... 48
6.8Interface Parameters ........................................................................................................ 49

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 5
6.8.1Adjustment of the Slave-Address (RS) .........................................................................49
6.8.2Adjustment of the Baud-Rate ........................................................................................49
6.8.3Adjustment of the Parity ................................................................................................49
6.9Using communication port RS232 or RS485 ....................................................................49
6.10Fault Recorder (FR) ..........................................................................................................50
6.10.1Fault Recorder...........................................................................................................50
6.10.2Number of fault recordings........................................................................................51
6.10.3Adjustment of the Trigger Event................................................................................51
6.10.4Pre-Trigger time (T_pre) ...........................................................................................51
6.11Setting of the clock............................................................................................................52
6.12Additional functions ...........................................................................................................52
6.12.1Blocking the protection functions ..............................................................................52
6.12.2Assignment of the output relays................................................................................53
6.12.3Assignment of the AR functions ................................................................................56
6.12.4Function assignment of the digital inputs..................................................................58
6.12.5Description of the digital input function .....................................................................58
6.13Measuring Value and Fault Indications.............................................................................59
6.13.1Measuring Value Indications .....................................................................................59
6.13.2Units of the measuring values displayed ..................................................................60
6.13.3Indication of fault data ...............................................................................................61
6.13.4Fault Memory ............................................................................................................62
6.14Reset .................................................................................................................................63
6.14.1Erasure of the Fault Memory.....................................................................................63
7.Notes on Relay Tests and Commissioning..............................................64
7.1Connection of the auxiliary voltage ...................................................................................64
7.2Testing of Output Relays and LEDs..................................................................................64
7.3Secondary injection test ....................................................................................................65
7.3.1Test equipment..............................................................................................................65
7.4Example of test circuit for MRIK3-C relays without directional feature ...........................66
7.4.1Checking the input circuits and measured values.........................................................66
7.4.2Checking the operating and resetting values of the relay.............................................67
7.4.3Checking the relay operating time.................................................................................67
7.4.4Checking the high set element of the relay...................................................................67
7.4.5Test circuit for MRIK3 relay with earth-current directional recognition (ER/XR models)
68
7.4.6Checking the auto reclosing function ............................................................................69
7.4.7Checking the circuit breaker position ............................................................................69
7.4.8Checking the AR blocking function ...............................................................................70
7.4.9Checking the external blocking and reset functions......................................................70
7.4.10Testing the external blocking with Block/Trip function ..............................................70
7.4.11Test of the CB failure protection................................................................................71
7.5Primary Test ......................................................................................................................71
7.6Maintenance......................................................................................................................71
8.Technical Data............................................................................................72
8.1Measuring input.................................................................................................................72
8.2Common data....................................................................................................................72
8.3Setting ranges and steps ..................................................................................................73
8.3.1System parameter.........................................................................................................73
8.3.2Time overcurrent protection (I-type)..............................................................................74
8.3.3Earth fault protection (E - type) .....................................................................................74
8.3.4Earth fault protection (ER/XR-type)...............................................................................74
8.3.5AR Parameter................................................................................................................75
8.3.6Control Function............................................................................................................76
8.3.7Interface parameter.......................................................................................................76
8.3.8Parameter for the fault recorder ....................................................................................76
8.4Tripping characteristics .....................................................................................................77
8.4.1Inverse time overcurrent protection relay......................................................................77
8.4.2Determination of earth fault direction (MRIK3-ER/XR) .................................................77
8.5Tripping characteristics .....................................................................................................78
8.6Output relays .....................................................................................................................81

Woodward Manual MRIK3-C EN
6 DOK-TD-MRIK3-C Rev. A
9.Order form..................................................................................................82

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 7
1.Comments on the manual
This manual explains in general the tasks of device planning, parameter setting, installation, com-
missioning, operation and maintenance of the MRIK3-C device.
The manual serves as working basis for:
•Engineers in the protection field,
•commissioning engineers,
•people dealing with setting, testing and maintenance of protection and control devices,
•as well as trained personnel for electrical installations and power stations.
All functions concerning the type code will be defined. Should there be a description of any func-
tions, parameters or inputs/outputs which do not apply to the device in use, please ignore that in-
formation.
All details and references are explained to the best of our knowledge and are based on our experi-
ence and observations.
This manual describes the (optionally) full featured versions of the devices.
All technical information and data included in this manual reflect their state at the time this docu-
ment was issued. We reserve the right to carry out technical modifications in line with further de-
velopment without changing this manual and without previous notice. Hence no claim can be
brought based on the information and descriptions this manual includes.
Text, graphic and formulae do not always apply to the actual delivery scope. The drawings and
graphics are not true to scale. We do not accept any liability for damage and operational failures
caused by operating errors or disregarding the directions of this manual.
No part of this manual is allowed to be reproduced or passed on to others in any form, unless
Woodward Kempen GmbH have approved in writing.
This user manual is part of the delivery scope when purchasing the device. In case the device is
passed on (sold) to a third party, the manual has to be handed over as well.
Any repair work carried out on the device requires skilled and competent personnel who need to be
well aware especially of the local safety regulations and have the necessary experience for working
on electronic protection devices and power installations (provided by evidence).
1.1 Information Concerning Liability and Warranty
Woodward Kempen GmbH does not accept any liability for damage resulting from conversions or
changes carried out on the device or planning (projecting) work, parameter setting or adjustment
changes done by the customer.
The warranty expires after a device has been opened by others than Woodward Kempen special-
ists.
Warranty and liability conditions stated in Woodward Kempen GmbH General Terms and Condi-
tions are not supplemented by the above mentioned explanations.

Woodward Manual MRIK3-C EN
8 DOK-TD-MRIK3-C Rev. A
1.2 IMPORTANT DEFINITIONS
The signal definitions shown below serve the safety of life and limb as well as for the appropriate
operating life of the device.
DANGER indicates a hazardous situation which, if not avoided, will
result in death or serious injury.
WARNING indicates a hazardous situation which, if not avoided,
could result in death or serious injury.
CAUTION, used with the safety alert symbol, indicates a hazardous
situation which, if not avoided, could result in minor or moderate in-
j
ury.
NOTICE is used to address practices not related to personal injury.
CAUTION, without the safety alert symbol, is used to address prac-
tices not related to personal injury.
1.3 How to use this instruction
In this instruction the technical description of all MRIK3-C versions is included. The user is given a
comprehensive insight into the various applications, the selection, installation, setting of parame-
ters and putting into operation of the MRIK3-C.
The manual MR- Digital multifunction relay describes the common part
of the MRIK3-C relay functionality e.g. how to change parameters. The
manual describe the device function which is equal to all HighTechLine
device types based on micro controller technology. E.g. MRI3, MRIK3,
MRN3, MU3, etc.
OUT-OF-DATE PUBLICATION
This publication may have been revised or updated since this copy
was produced. To verify that you have the latest revision, be sure
to check the Woodward documentation website:
www.woodward.com
If your publication is not there, please contact your customer ser-
vice representative to get the latest copy.

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 9
1.4 Electrostatic Discharge Awareness
All electronic equipment is electro static-sensitive, some components
more than others. To protect these components from electro static
damage, you must take special precautions to minimize or eliminate
electrostatic discharges.
Follow these precautions when working with or near the control.
1. Before doing maintenance on the electronic control, discharge the
static electricity on your body to ground by touching and holding a
grounded metal object (pipes, cabinets, equipment, etc.).
2. Avoid the build-up of static electricity on your body by not wearing
clothing made of synthetic materials. Wear cotton or cotton-blend
materials as much as possible because these do not store static
electric charges as much as synthetics.
3. Keep plastic, vinyl, and Styrofoam materials (such as plastic or
Styrofoam cups, cup holders, cigarette packages, cellophane
wrappers, vinyl books or folders, plastic bottles, and plastic ash
trays) away from the control, the modules, and the work area as
much as possible.
4. Do not remove any printed circuit board (PCB) from the control
cabinet unless absolutely necessary. If you must remove the PCB
from the control cabinet, follow these precautions:
Do not touch any part of the PCB except the edges.
Do not touch the electrical conductors, the connectors, or the
components with conductive devices or with your hands.
When replacing a PCB, keep the new PCB in the plastic antistatic
protective bag it comes in until you are ready to install it.
Immediately
after removing the old PCB from the control cabinet, place it in
the
antistatic protective bag.
To prevent damage to electronic components caused by improper
handling, read and observe the precautions in Woodward manual 82715,
Guide for Handling and Protection of Electronic Controls, Printed Circuit
Boards, and Modules.
Woodward Kempen GmbH reserves the right to update any portion of this publication at any
time. Information provided by Woodward Kempen GmbH is believed to be correct and relia-
ble. However, no responsibility is assumed by Woodward Kempen GmbH unless otherwise
expressly undertaken.
© Woodward Kempen GmbH All Rights Reserved

Woodward Manual MRIK3-C EN
10 DOK-TD-MRIK3-C Rev. A
2.Introduction and Application
The digital net protection relay MRIK3-C an universal time - over -current and earth fault relay with
integrated control- and supervision function as well as optional an integrated auto reclosing func-
tion The earth fault protection is applicable for insulated and compensated grids. The controlling of
the circuit breaker take place by the means of the front plate via push button in the case of a local
operation, the remote operation can be done via digital inputs or via the serial communication inter-
face.
The earth-fault supervision is either realised in Holmgreen connection or by means of a core-type
current transformer. The MRIK3-C is available with rated currents of 1 A or 5 A.
3. Characteristics and Features
Microprocessor technology with self-supvervision,
Measuring of phase currents as RMS value,
Digital filtering of the earth current with discrete Fourier analysis, by which the influence of
interference signals, such as harmonics and transient DC components during an earth-fault are
suppressed.
Two sets of parameters,
Operation cycle counter,
Suppression of an LED indication after activation (LED flash),
Selectable protective functions : Definite time overcurrent protection (DMT) and inverse
time overcurrent protection (IMT),
Selectable IMT trip characteristics of IEC 255-4:
Normal inverse (Type A)
Very inverse (Type B)
Extremely inverse (Type C)
Special-purpose characteristics eg. RINV, LINV and RXIDG in earth path
Reset mode for DMT/IMT trip characteristics is selectable,
Definite element for short-circuit high-speed trip
Defined time overcurrent protection without directional feature (DEFT)
Inverse time overcurrent protection without directional feature (INV)
Two element defined- or inverse time earth fault protection,
Optionally with integrated directional feature for the earth fault element.
Control of the CB via potential free auxiliary relays,
Supervision of the CB via digital wide range inputs,
Remote indication of the CB position via serial interface.,
CB failure protection,
Display of the measuring values as primary quantities,
Measuring of the phase currents during short-circuit free operation,
Blocking of the individual protective elements or the trip elements can be set freely,
The protective functions can be freely allocated to the output relays. (Relay Matrix),
automatic auto reclosing (optional),
free assignment of protective function for every reclosing separately adjustable,
Free assignment of the input function to the digtial input,
Saving of trip values and the switch-off times (tCBFP) of 25 fault events (voltage fail-safe),
Recording of up to 8 fault events with time stamp,
Display of date and time,
Trip via digital inputs,
Rack mounting, with self-acting short-circuit mechanism for CT circuits,
Possibility of serial data exchange via the RS485 or RS232 interface, with Modbus Proto-
col.
The minimum operating time including boot time (power-on-time) is <100ms

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 11
4.Design
4.1 Connections
Figure 4.1: Connection diagram MRIK3-ICE
Figure 4.2: Connection diagram MRIK3-ICER/ICXR

Woodward Manual MRIK3-C EN
12 DOK-TD-MRIK3-C Rev. A
Figure 4.3: Measuring of phase currents and earth current detection in Holmgreen connection (IE)
This kind of connection can be used where three phase CTs are available and a combination of
phase and earth current measuring is required.
Figure 4.4: Measuring of earth current with core-type CT (IE)
With the combination of phase and earth current measuring, CTs to be connected according to
Figure 4.3 or Figure 4.4.
P1
P2
S1
S2
P1
P2
S1
S2
P1
P2
S1
S2
I1
I2
I3
IE
L1.1
B3
B4 L1.2
L2.1
B5
L2.2
B6
L3.1
B7
L3.2B8
B1
B2
L
1
L2
L3

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DOK-TD-MRIK3-C Rev. A 13
4.1.1 Analog input circuits
The analog input signals of the phase currents IL1 (B3 - B4), IL2 (B5 - B6), IL3 (B7 - B8) and the earth
current IE(B1 - B2) are fed to the protection device via separate input CTs. The current measuring
quantities are galvanical decoupled, analogously filtered, and then fed to the analog/digital con-
verter.
For the unit type with earth fault directional features (ER/XR-relay type) the residual voltage from
the open delta winding can directly be connected to A3 and A2.
See chapter 5.6 for voltage transformer connections on isolated/compensated systems (direction
feature of the earth fault element)
4.1.2 Output relays
The MRIK3-C has 5 output relays. Two of these relays with two change-over contacts and three re-
lays with one change-over contact each are used for signalling. The protective functions can be
freely allocated except of those for the self-supervision relay.
Relay 1: C1, D1, E1 and C2, D2, E2
Relay 2: C3, D3, E3 and C4, D4, E4
Relay 3: C5, D5, E5
Relay 4: C6, D6, E6
Relay 5: Self-supervision C7, D7, E7
All relays are operating according to the n. o. principle with the exception of the self-supervision re-
lay, which operates acc. to the n. c. principle.
4.1.3 Digital inputs
The MRIK3-C has 7 digital inputs with fixed functions. The input functions can be selected free for
each digital input. All inputs have a common reference point: Terminal D8. (See chapter 6.12.4 /
6.12.5) MR – Digital multifunction relays
Terminal Function Code jumper
C8 Digital Input 1 X6
E8 Digital Input 2 X7
A2 Digital Input 3 X5
A5 Digital Input 4 X4
A6 Digital Input 5 X1
A7 Digital Input 6 X2
A8 Digital Input 7 X3

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14 DOK-TD-MRIK3-C Rev. A
4.1.4 Low/High range of the digital Inputs
The MRI(K)3-C is equipped with a wide-range power supply unit and hence the supply voltage is
freely selectable. The switching threshold of the digital inputs, however, has to be fixed in compli-
ance with the supply voltage. Two different switching thresholds can be adjusted:
Range Plug UAB U
AN
Low Plugged in <= 8V >= 10V
High Open <= 60V >= 80V
Figure 4.5: Code jumpers

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 15
4.2 Password
4.2.1 Code jumpers
Behind the front plate of the MR-relays there are three code jumpers to preset the following func-
tions:
Password programming
Output relay functions
The following figure shows the position and designation of the code jumpers:
4.2.2 Password programming
The two different passwords are assigned to sepa-
rate password sections.
Password 1 (Code jumper 1) With this password all
protection parameter are changeable.
Password 2 (Code jumper J2) With this password it
is allowed to change the mode of the relay from
“remote control” to “local control” and also allowed
to control the CB. (See Chap. 5.7.8) The procedure
for password programming is described in Chapter
4.4 of the description MR – digital multifunction re-
lays.
Figure 4.6: Code jumpers
Code jumper Function Code jumper
position
Operation mode
J1 Password 1* OFF Normal position
general ON Password selection (see general description
MR chapter 4.4)
J2 Password 2* OFF Normal position
Control-level ON Password selection (see general description
MR chapter 4.4)
J3 Reset OFF Output relays will be reset automatically
ON no function
Table 4.1: Summary of coding possibilities
*If both code jumpers are set it is not possible to change the password.

Woodward Manual MRIK3-C EN
16 DOK-TD-MRIK3-C Rev. A
4.3 Front plate (for –ICE relay type)
Figure 4.7: Front plate MRIK3-ICE
The LEDs No, RS and on the MRIK3-C emit a yellow
light, all other LEDs are bi-coloured. The LEDs at the
left next to the alphanumerical display give a green
light during measuring and a red one when a fault sig-
nal occurs.
The LEDs underneath the <SELECT/RESET> - push
button emit a green light during adjustment and inquiry
of the setting quantities left to the LEDs. They show a
red light if the printed setting quantities right to the
LEDs are activated.
4.3.1 Indicating LEDs
L1, L2, L3 Indication of the phase currents
E Indication of the earth current
Date and time
I2t Indication for the composite switch
off power of the CB.
No operation cycle counter
FR Parameter for the fault recorder
RS Setting of the relay address
4.3.2 Adjusting LEDs
I> Overcurrent setting
I>> Short-circuit setting
IE> Earth overcurrent setting
IE>> Earth short circuit setting
CHAR Selection of characteristics
t> emits in combination with all time
delay settings
DI Assignment of input functions to the
digital inputs.
01 AR Autoreclosing unsuccessful
Trip ext. tripping
Block Trip/Blockage time
I²t> Pick up level for the composite switch
off power
SHOT number off AR shots
tF fault time
tD1 dead time before 1. AR
tD2 dead time before 2. AR
tD3 dead time before 3. AR
tD4 dead time before 4. AR
tCl close impulse time
tR reclaim time
P2 Parameter set 2 is active
CB red CB ist switched on
CB green CB is switched off
CB blinking CB has faults

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 17
4.4 Front plates (for -ER/-XR-relay types)
Figure 4.8: Front plate MRIK3-ICER MRIK3-ICXR
The LEDs IP, IQ, RS and FR on the MRIK3-ICE and
MRI3-ICE emit a yellow light, all other LEDs are bi-
coloured. The LEDs at the left next to the alphanumeri-
cal display give a green light during measuring and a
red one when a fault signal occurs.
The LEDs underneath the <SELECT/RESET> - push
button emit a green light during adjustment and inquiry
of the setting quantities left to the LEDs. They show a
red light if the printed setting quantities right to the
LEDs are activated.
4.4.1 Indicating LEDs
L1, L2, L3 Indication of the phase currents
E Indication of the earth current
Date and time
green: forward direction; red: reverse
direction
IPIndication of the active component of
the earth fault current
IQIndication of the reactive component
of the earth fault current.
FR Parameter for the fault recorder
RS Setting of the relay address
4.4.2 Adjusting LEDs
I> Overcurrent setting
I>> Short-circuit setting
IE> Earth overcurrent setting
IE>> Earth short circuit setting
CHAR Selection of characteristics lights in
combination with all time delay
settings.
DI Assignment of the input functions to
the digital inputs
Trip ext. tripping
SHOT Number of AR shots
tF max. fault time
tD1 dead time before 1. AR
tD2 dead time before 2. AR
tD3 dead time before 3. AR
tD4 dead time before 4. AR
tCl max close impulse time
tR reclaim time
FR Parameter for the fault recorder
RS Setting of the relay address
P2 Parameter set 2 is active
CB red CB is switched on
CB green CB is switched off
CB blinking CB has faults

Woodward Manual MRIK3-C EN
18 DOK-TD-MRIK3-C Rev. A
5.Working principle
5.1 Analogue circuits
The incoming currents from the main current transformers on the protected object are converted to
voltage signals in proportion to the currents via the input transformers and burden. The noise sig-
nals caused by inductive and capacitive coupling are suppressed by an analogue R-C filter circuit.
The analogue voltage signals are fed to the A/D-converter of the microprocessor and transformed
to digital signals through Sample- and Hold-circuits. The analogue signals are sampled at 50 Hz
(60 Hz) with a sampling frequency of 800 Hz (960 Hz), namely, a sampling rate of 1.25 ms (1.04
ms) for every measuring quantity.
5.2 Digital circuits
The essential part of the MRIK3-C relay is a powerful microcontroller. All of the operations, from the
analogue digital conversion to the relay trip decision, are carried out by the microcontroller digitally.
The relay program is located in an EPROM (Electrically-Programmable-Read-Only-Memory). With
this program the CPU of the microcontroller calculates the three phase currents and ground current
in order to detect a possible fault situation in the protected object.
For the calculation of the current value an efficient digital filter based on the Fourier Transformation
(DFFT - Discrete Fast Fourier Transformation) is applied to suppress high frequency harmonics
and DC components caused by fault-induced transients or other system disturbances.
The calculated actual current values are compared with the relay settings. If a phase current ex-
ceeds the pickup value, an alarm is given and after the set trip delay has elapsed, the correspond-
ing trip relay is activated.
The relay setting values for all parameters are stored in a parameter memory (EEPROM - Electri-
cally Erasable Programmable Read-only Memory), so that the actual relay settings cannot be lost,
even if the power supply is interrupted.
The microprocessor is supervised by a built-in "watchdog" timer. In case of a failure the watchdog
timer resets the microprocessor and gives an alarm signal, via the output relay "self supervision".
5.3 Status descriptions
Reaction to protection events is possible at any time unless blocking is expressly desired (refer to
6.12.1). In the inactive and blocked state auto reclosing is not possible.
For the explanation of the functional sequence the following six status transitions are defined.
5.3.1 „Inactive“
The relay MRIK3-C is in "inactive" status if one of the following conditions is fulfilled:
The circuit breaker is in position "OFF",
the unit is in "blocked" status,
the unit is not in "starting/cycle" status
5.3.2 „Reclaim time“ tR
The relay MRIK3-C is in "reclaim time" status (tR) when the reclaim time
has not yet expired or
not interrupted by other incidents.

Manual MRIK3-C EN Woodward
DOK-TD-MRIK3-C Rev. A 19
5.3.3 „AR-ready“
The relay MRIK3-C is in position "AR-ready" status when the following conditions are fulfilled:
The circuit breaker is in position "ON",LED CB emit red light
the reclaim time has expired,
the unit is not in "blocked" status,
the unit is not in "starting cycle" status.
Only in "AR-ready" status a reaction of the AR-unit to the protection incidents is possible!
5.3.4 „AR-starting“ (dead time)
In "AR-starting" status the start conditions for an automatic reclosing by means of the protection
commands and the circuit breaker position are checked.
5.3.5 „AR-cycle“ (auto reclosing)
The reclosing commands are carried out in "AR-cycle" status by means of the conditions and the
presetting. The results (AR successful or unsuccessful) are evaluated accordingly.
5.3.6 „AR-blocked“
Unit MRIK3-C changes immediately to "AR-blocked" status when an external or internal blocking
signal (A2-A3) exists. (activation via assigned digital input, see Chap. 6.12.4). No auto reclosing is
possible in "AR-blocked" status.
5.3.7 „Fast Trip Mode“
By way of the function "Assignment of the AR functions" it is possible to activate or deactivate a
Fast Trip function for each AR stage and for each protective function. This is applicable for tripping
before the 1st AR up to tripping after the last AR. (see chapter 6.12.3)
5.3.8 „Blocking mode“
By way of the function "Assignment of the AR functions" it is possible to activate or deactivate a
protection function for each AR stage. This is applicable for tripping before the 1st AR up to tripping
after the last AR. (see chapter 6.12.3)
5.3.9 „Activating of AR“
Prior to every AR it is possible to stipulate which kind of tripping (I> or I>>, etc.) will lead to auto-
matic reclosing. This can be separately fixed for each AR stage. (see chapter 6.12.3)

Woodward Manual MRIK3-C EN
20 DOK-TD-MRIK3-C Rev. A
5.3.10 Description of the status transition
to
from inactive reclaim time ready starting (dead time) cycle (auto reclosing) blocked
inactive C.B. manual
ON
external
blocking
signal
reclaim
time reclaim time
expired
external
blocking
signal
ready C.B. OFF protection
energized
and/or
tripped and
C.B.-energy
OK
external
blocking
signal
starting starting con-
ditions not
fulfilled
start signal
interrupted
start condi-
tions fulfilled
(fault time,
C.B. OFF
etc.)
external
blocking
signal
cycle AR takes
place
external or
internal
blocking
signal
blocked external
reset of
blocking
Table 5.1: AR-status transition matrix
From Table 5.1 you can detect what status transitions of MRIK3-C are possible. When the unit is
for instance in "cycle" status (see also para. 4.3) only two status transitions are possible:
status transition to "ready"-status when the auto reclosing takes place
status transition to "blocked" status by external or internal blocking.
The grey shaded sections indicate that no transition is possible.
5.3.11 AR information inputs
By means of the information inputs the MRIK3-C decides whether and when automatic reclosing
may take place. The functions are assigned via the function assignment of the digital inputs as far
as they are required. (refer to chapter 6.12.5)
If one of the three CB position indicators described in the following is activated, it must also be
used because otherwise no correct function indication is possible.
CR = "CB ready" signal (e.g. motor switch or spring power storage)
With this function the CB ready message is signalled.
CI = "CB feedback CB – ON"
With this function the CB position ON is signalled. Signal = 1 = CB is switched on.
CO = "CB feedback CB – OFF
With this function the CB position OFF is signalled. Signal = 1 = CB is switched off.