Woodward MRP2 User manual

MRP2 - Directional Power Relay
(May 2008)
Manual MRP2 (Revision New)

Woodward Manual MRP2 GB
2 TD_MRP2_05.08_GB_Rev.New
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 1994-2008

Manual MRP2 GB Woodward
TD_MRP2_05.08_GB_Rev.New 3
Contents
1.Introduction and application ....................................................................... 5
2.Features and characteristics....................................................................... 6
3.Design ........................................................................................................... 7
3.1Connections ...................................................................................................................... 7
3.1.1Analog input circuits ...................................................................................................... 8
3.1.2Output relays................................................................................................................. 8
3.1.3Blocking input................................................................................................................ 8
3.1.4External reset input ....................................................................................................... 8
3.2LEDs ............................................................................................................................... 10
4.Working principle ....................................................................................... 11
4.1Analog circuits................................................................................................................. 11
4.2Digital circuits .................................................................................................................. 11
4.3Measuring principle ......................................................................................................... 12
4.4Demand imposed on the main current transformers ....................................................... 12
5.Operations and settings ............................................................................ 13
5.1Display ............................................................................................................................ 13
5.2Setting procedure............................................................................................................ 14
5.2.1Pickup value for power increase (P>), power decrease (P<) and reverse power (Pr) 14
5.2.2Pickup value for under voltage U<Pr of the voltage dependent reverse power
element ....................................................................................................................... 15
5.2.3Tripping times for power increase (P>), power decrease (P<) and reverse
power (Pr) ................................................................................................................... 15
5.2.4Y/Δ- Change-over of the input transformers............................................................... 16
5.2.5Circuit breaker failure protection tCBFP ......................................................................... 17
5.2.6Selection of the rated voltage (100V/110V)................................................................. 17
5.2.7Display of the activation storage (FLSH/NOFL) .......................................................... 17
5.2.8Adjustment of the slave address ................................................................................. 17
5.2.9Setting of Baud rate (applies for Modbus Protocol only) ............................................. 17
5.2.10Setting of parity (applies for Modbus protocol only) ................................................ 17
5.2.11Blocking the protection functions and assignment of the output relays................... 18
5.3Indication of measuring values and fault data ................................................................. 20
5.3.1Indication of measuring values.................................................................................... 20
5.3.2Indication of fault data ................................................................................................. 20
5.3.3Fault Recorder ............................................................................................................ 21
5.4Reset............................................................................................................................... 22
5.5Hints for the setting procedure ........................................................................................ 22
5.5.1Setting of the power measuring circuits switching point.............................................. 22
6.Relay Testing and commissioning ........................................................... 24
6.1Power-On ........................................................................................................................ 24
6.2Testing the output relays................................................................................................. 24
6.3Checking the set values .................................................................................................. 25
6.4Secondary injection test .................................................................................................. 25
6.4.1Test equipment ........................................................................................................... 25
6.4.2Example of test circuit for MRP2 relay ........................................................................ 26
6.4.3Checking the input circuits and measured values ....................................................... 27
6.4.4Checking the operating and resetting values of the relay ........................................... 27
6.4.5Checking the relay operating time............................................................................... 27
6.4.6Test of the CB failure protection.................................................................................. 28
6.4.7Checking the external blocking and reset functions .................................................... 28
6.5Primary injection test....................................................................................................... 29
6.6Maintenance.................................................................................................................... 29
7.Technical data ............................................................................................ 30
7.1Measuring input circuits .................................................................................................. 30
7.2Common data.................................................................................................................. 30
7.3Setting ranges and steps ................................................................................................ 31

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4 TD_MRP2_05.08_GB_Rev.New
7.3.1Setting ranges and steps MRP2-1 and MRP2-3.......................................................... 31
7.3.2Setting ranges and steps MRP2-R1 and MRP2-R3 .................................................... 31
7.3.3Interface parameters ................................................................................................... 32
7.4Output contact ratings ..................................................................................................... 32
8.Order form................................................................................................... 33

Manual MRP2 GB Woodward
TD_MRP2_05.08_GB_Rev.New 5
1. Introduction and application
The power relay MRP2 is used in 3-phase systems for active power measurement.
In the single-phase relay type MRP2-1, the load of the three phases is assumed to be symmetrical
so that a single phase power measurement can be realized.
For application fields (i.e. turbine movers) where two reverse power switching points with higher
precision are required, the relay type MRP2-R is avail-able.
Among others, the MRP2-relays serve:
•for supervision of load flow between two systems. (MRP2)
If the generated power of one system fails, unimportant consumers have to be disconnected by the
power relay. Thereby the mains is stabilized and the supply of important consumers maintained. If
gen.-sets are operating in parallel, these consumers can be disconnected if the load remains below
the set minimal value or - in peak load operating mode - they can be connected if a limit value for
the mains power is exceeded.
•as reverse power relay to protect turbines and Diesel gen.-sets from reverse power if this
prime mover fails. (MRP2 and MRP2-R)
For generators operating in parallel with a mains or another generator, it is imperative to supervise
the power direction. If for example the prime mover fails the alternator operates as a motor and
drives the prime mover (diesel or turbine). The MRP2 "recognizes" the reverse of the power direc-
tion and - in case of this error - switches off the alternator. This way, power losses and damages of
the prime mover are avoided.
•as voltage dependent reverse power relay for mains decoupling
The criterium for tripping the voltage-dependent reverse power element is the reverse power with
simultaneous voltage decrease as a result of an external mains fault. Decoupling prevents external
mains faults from affecting the own mains section. Internal faults are selectively detected by other
protection devices.

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2. Features and characteristics
Unit MRP2 still has another feature besides those described in the general MR-description,
namely:
•Measuring of the actual power by means of multiplication and integration of the
instantaneous values of current and voltage.
•Correct measuring even at unequally loaded phases (MRP2-3).
•Switchable measuring for delta or star connection of v.t.'s.
•Indication of current, voltage and power
•Serial interface
•Three adjustable power switching-points.
•voltage dependent reverse power element
•Plug-in type design with automatic short-circuiters for current transformer circuits.
•Circuit Breaker failure protection
•Storing of trip values and breaking times (tCBFP) of eight fault events
•Ability of serial data transmission via RS485 interface optional with SEG RS485 Pro Open
Data Protocol or Modbus Protocol

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TD_MRP2_05.08_GB_Rev.New 7
3. Design
3.1 Connections
Figure 3.1: Connection diagram MRP2-1 and MRP2-R1 (Star-/Delta adjustment has to be set to DELTA)
Figure 3.2: Connection diagram MRP2-3 and MRP2-R3 (Star-/Delta adjustment has to be set to Y)

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8 TD_MRP2_05.08_GB_Rev.New
Figure 3.3: Voltage transformer in V-connection
3.1.1 Analog input circuits
The analog input signals of the conductor currents IL1 (B3-B4), IL2 (B5-B6), IL3 (B7-B8) and the
phase voltages U1 (A3), U2 (A5), U3 (A7) with A8 as star point are each transmitted to the protec-
tion device MRP2-3 by means of separate input transformers (star connection).
At the single-phase version of unit MRP2-1 the in-put signals are also transmitted via separate in-
put transformers: IL1 (B3-B4); U1 (A3-A4).The constantly measured current values are galvanically
decoupled, filtered by a low pass-filter and finally fed to the analog/digital converter.
3.1.2 Output relays
The MRP2 is equipped with 5 output relays. Apart from the relay for self-supervision, all protective
functions can be optionally assigned:
•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
•Self-supervision C7, D7, E7
All trip and alarm relays are working current relays, the relay for self supervision is an idle current
relay.
3.1.3 Blocking input
The function for blocking can be parameterized arbitrary. When an auxiliary voltage is connected to
D8/E8 those relay functions will be blocked which were parameterized before (refer to chapter
5.2.6).
3.1.4 External reset input
Please refer to chapter 5.4

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Figure 3.4: Front plate MRP2-1 and MRP2-R1
Figure 3.5: Front plate MRP2-3 and MRP2-R3

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3.2 LEDs
Measuring values will be indicated on display together with the LEDs P, L1, L2, L3, U and I (refer to
chapter 5.3).
The MRP2 provides one LED to indicate the power direction (green and red arrow). Green indi-
cates generator power, red indicates reverse power.
For setting and indication of protection trippings the LEDs beneath the push buttons are used.
The five LEDs below push-button <SELECT/RESET> are bi-colored: green relates to P>, P<, Pr,
U<Pr, Δ/Y, red relates to tp>, tp< and tpr and tU<Pr.
The LED marked with letters RS lights up during setting of the slave address of the device for serial
data communication.

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4. Working principle
4.1 Analog circuits
The incoming currents from the main current trans-formers 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 analog R-C filter circuit.
The analog voltage signals are fed to the A/D-converter of the microprocessor and transformed to
digital signals through Sample- and Hold- circuits. The measuring value detection takes with a
sampling frequency of 900 Hz (1080 Hz), namely, a sampling rate of 1.11 ms (0.93 ms) for every
measuring quantity at 50 Hz (60 Hz).
4.2 Digital circuits
The essential part of the MRP2 relay is a powerful microcontroller. All of the operations, from the
analog digital convertion to the relay trip decision, are carried out by the microcontroller digitally.
By means of a special protective routine stored in the EPROM, the microprocessor processes cur-
rents and voltages at the analog inputs and then - based on the measured values - calculates the
existing power.
The measured power is permanently compared with the threshold value stored in the parameter
memory (EEPROM - Electrically Erasable Programmable Read- Only Memory). If a measured
power exceeds the pickup value, an alarm is given and after the set trip delay has elapsed, the cor-
responding trip relay is activated.
The relay setting values for all parameters are stored in a parameter memory (EEPROM), so that
the actual relay settings cannot be lost, even if the power supply is interrupted.
The microprocessor is supervised through a built-in "watch dog" timer. In case of a failure the
watch dog timer resets the microprocessor and gives an alarm signal, via the output relay "self su-
pervision".

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12 TD_MRP2_05.08_GB_Rev.New
4.3 Measuring principle
Through multiplication of the actual current and voltage values p(t) = u(t) ·i(t), the microprocessor
calculates the phase power. 18 instantaneous values are measured and recorded per cycle. After-
wards the power value during one cycle is deter-mined.
1
󰇛󰇜·
Consequently, the total three phase current is calculated from: Ptotal = P1 + P2 + P3
Figure 4.1: Power measurement
4.4 Demand imposed on the main current transformers
The current transformers must be designed in such a manner that they are precisely dimensioned
for pure reverse power in the lower range especially with the MRP2-R. We therefore recommend
the use of measuring transformers which are at least type 1M5. The low energy consumption of the
MRP2-R of <0.2 VA has a positive effect on the design of the current transformers.

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TD_MRP2_05.08_GB_Rev.New 13
5. Operations and settings
5.1 Display
Function Display shows Pressed pushbutton Correspond-
ing LED
Normal operation SEG
Measured operating values
phase voltages,
phase currents,
power and power direction
Actual measured
voltage UL1, UL2, UL3,
UL12, UL23, UL31
current IL1, IL2, IL3
power Ptot, PL1, PL2, PL3
<SELECT/RESET>
one time for each value
L1/U, L2/U,
L3/U,
L1/I, L2/I, L3/I
→← P/L1/L2/L3
Setting values
delta/star-connection adjustment
DELT or Y <SELECT/RESET><+><-> Δ/Y
power increase
trip delay for power increase
setting value in PN
setting value in seconds
<SELECT/RESET>
one time for each value
P>
tP>
power decrease/reverse power
trip delay for power decrease
setting value in PN
setting value in seconds
<SELECT/RESET>
one time for each value
P<
tP<
reverse power
trip delay for reverse power
setting value in PN
setting value in seconds
<SELECT/RESET>
one time for each value
Pr
tP
r
undervoltage U<Pr
trip delay tU<P
r
setting value in volts
setting value in seconds
<SELECT/RESET>
one time for each value
U<Pr
tU<P
r
Function blockade EXIT <+> until max. setting value LED of blocked
parameter
Circuit breaker failure protection CBFP <SELECT/RESET><+><-> L1, L2, L3, →
←
*
P>, P<, Pr, U<P
r
Indication of memorized pickup FLSH/NOFL <SELECT/RESET><+><->
Selection of rated voltage 100 V/110 V <SELECT/RESET><+><-> U
Slave address of serial
interface
1-32 <SELECT/RESET><+><-> RS
Recorded fault data of power Measured values in the
instant of tripping
<SELECT/RESET>
one time for each value
L1, L2, L3, P>,
P<, Pr* →←
Recorded fault data of voltage
U1, U2, U3
Measured values in volts <SELECT/RESET>
one time for each value
L1, L2, L3 and
U*
Recorded fault data of current I1,
I2, I3
Measured values related
to In
<SELECT/RESET>
one time for each value
L1, L2, L3 and I*
Save parameter? SAV? <ENTER>
Save parameter! SAV! <ENTER> for about 3 s
Software version First part (e.g. D16-)
Second part (e.g. 5.01)
<TRIP>
one time for each part
Manual trip TRI? <TRIP>
three times
Inquire password PSW? <SELECT/RESET>
<+><-><ENTER>
Relay tripped TRIP <TRIP>
or after fault tripping
L1, L2, L3, →
←
*
P>, P<, Pr
Secret password input XXXX <SELECT/RESET>
<+><-><ENTER>
System reset
⏐
SEG <SELECT/RESET>
for about 3 s
Table 5.1: Possible indication messages on the display
* The units MRP2-1 and MRP2-R1 with single-phase power measurement have only the
LED P available instead of LED L1, L2 and L3

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5.2 Setting procedure
After push button <SELECT/RESET> has been pressed, always the next measuring value is
indicated. Firstly the operating measuring values are indicated and then the setting parameters. By
pressing the <ENTER> push button the setting values can directly be called up and changed. For
parameter setting a password has to be entered. (please refer to chapter 4.4 of description "MR-
Digital Multifunctional Relays")
5.2.1 Pickup value for power increase (P>), power decrease (P<) and re-
verse power (Pr)
After setting of the pickup value to supervise power increase, (P>), power decrease (P<) and re-
verse power (Pr), the display indicates a value that is related to the three phase nominal power PN
of the unit. This means:
Pickup value = indicated value x nominal power
(PN= √3·UN·INwith UN= phase to phase voltage).
Push-buttons <+> or <-> can be pressed to change, <ENTER> to store the indicated value.
It is also possible to use the power decrease relay (P<) as a second reverse power relay. If applied
for reverse power protection, the parameters for P< have to be adjusted to „negative values“, the
value which is used for Pr must be set „positive“.
In the MRP2-R (reverse power relay with increased precision) unit version, the value for a power
increase in forward direction P> can only be set to 0,5 x Pn and must therefore - as a rule - be
blocked by means of setting „EXIT“.
The functions P> and Pr are blocked each by incrementing via push-button <+> until „Exit“ appears
on the display and storage with push-button <ENTER>. P< is deactivated by incrementing the set
value via push-button <-> until „EXIT“ appears on the display. This entry as well has to be stored
via push-button <ENTER>.If trip time is set to exit but not so the threshold belonging to it, tripping
is blocked. In case of failure, the belonging alarm relay picks up nevertheless.
Tripping takes place if the sum total of individual loads exceeds or drops below the set value.

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TD_MRP2_05.08_GB_Rev.New 15
5.2.2 Pickup value for under voltage U<Pr of the voltage dependent reverse
power element
When the threshold value of the secondary voltage excitation is being adjusted, the display shows
a response value in voltage. The voltage-dependent reverse power element is excited when the
device measures a reverse power greater than Pr (set value see 5.2.1) and a secondary voltage
smaller than U<Pr in at least one phase.
The displayed set values can be changed with the keys <+> and <-> and stored with <ENTER>.
Figure 5.1: Reverse power element Pr and voltage dependent reverse power element PrU<
5.2.3 Tripping times for power increase (P>), power decrease (P<) and re-
verse power (Pr)
After setting of the tripping times a value indicated in seconds is shown on the display. The re-
quired time delay can be entered by means of push-buttons <+> and <-> and is stored via
<ENTER>.

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5.2.4 Y/Δ- Change-over of the input transformers
The voltage sensing circuits of the MRP2 may be connected in either star or delta configuration.
The relay rated voltage, UN, refer to the line-line voltage in the star connection. When the relay is
connected in the delta connection the maximum line-to-line voltage must be reduced to 1/√3 x UN.
During parameter setting the connection configuration either in star or delta has to be specified.
For the single-phase type (MRP2-1) phase-to-phase voltage U12 or phase-to-neutral voltage U1E
can be connected to terminals A3/A4. Pay attention to the correct setting of the star or delta ad-
justment.
Figure 5.2: Input transformers in delta-connection (MRP2-3)
Figure 5.3: Input transformers in star-connection (MRP2-3)

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5.2.5 Circuit breaker failure protection tCBFP
The CB failure protection is based on supervision of phase currents during tripping events. Only af-
ter tripping this protective function becomes active. The test criterion is whether all phase currents
are dropped to <1% x INwithin tCBFP (Circuit Breaker Failure Protection - adjustable between 0.1 -
1.6s). If not all of the phase currents have dropped to <1%xINwithin this time, CB failure is detected
and the related relay activated. The CB failure protection function is deactivated again as soon as
the phase currents have dropped to <1%xINwithin tCBFP
5.2.6 Selection of the rated voltage (100V/110V)
Relay types with a rated voltage of 100 V can optionally be adjusted to 110 V rated voltage. This
simplifies calculation of the trip value of 110 V systems. This parameter can be changed by push
buttons <+> and <-> and saved by pressing <ENTER>.
5.2.7 Display of the activation storage (FLSH/NOFL)
If after an activation the existing power drops again below the pickup value, e.g. P>, without a trip
has been initiated, LED P> signals that an activation has occurred by flashing fast. The LED keeps
flashing until it is reset again (push button <RESET>). Flashing can be suppressed when the pa-
rameter is set to NOFL.
5.2.8 Adjustment of the slave address
Pressing push buttons <+> and <-> the slave address can be set in the range of 1 - 32. LED RS
lights up during setting procedure.
5.2.9 Setting of Baud rate (applies for Modbus Protocol only)
Different transmission rates (Baud rate) can be set for data transmission via Modbus protocol.
The rate can be changed by push buttons <+> and
<-> and saved by pressing <ENTER>.
5.2.10 Setting of parity (applies for Modbus protocol only)
The following three parity settings are possible :
•"EVN" = even
•"ODD" = odd
•"NO" = no parity check
The setting can be changed by push buttons <+> and <-> and saved by pressing <ENTER>.

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5.2.11 Blocking the protection functions and assignment of the output relays
The blocking function of the MRP2 can be set ac-cording to requirement. By applying the voltage
(in the range from aux. voltage) to D8/E8, the functions chosen by the user are blocked. Setting of
the parameter should be done as follows:
Setting of blocking input:
•Following the simultaneous activation of the <ENTER> and <TRIP> keys the display shows
the text „BL=1“ (the blocking function is active if auxiliary voltage is fed) or „BL=0“ (the
blocking function is active if auxiliary voltage is missing).
•By pressing push buttons <+> <-> the value displayed can be changed.
•The changed value is stored by pressing <ENTER> and entering the password.
Function Display
BLOC Blockage activ BL=1
Table 5.2: Default settings blocking parameters
Blocking the protection functions:
•When pressing push buttons <ENTER> and <TRIP> at the same time, message "BLOC" is
displayed (i.e. the respective function is blocked) or "NO_B" (i.e. the respective function is
not blocked). The LED allocated to the first protection function P> lights red.
•By pressing push buttons <+> <-> the value displayed can be changed.
•The changed value is stored by pressing <ENTER> and entering the password.
•By pressing the <SELECT/RESET> push button, any further protection function which can
be blocked is displayed.
•Thereafter the blocking menu is left by pressing <SELECT/RESET> again.
Function Display LED/Colour
P> power increase BLOC P> yellow
P< power decrease BLOC P< yellow
Pr reverse power BLOC Pr yellow
U<Pr undervoltage BLOC U<P
r
red
CBFP C.B. failure protection NO_B
Table 5.3: Default settings of blocking functions
Assignment of the output relays:
Unit MRP2 has five output relays. The fifth output relay is provided as permanent alarm relay for
self supervision is normally on. Output relays 1 - 4 are normally off and can be assigned as alarm
or trip-ping relays to the power functions which can either be done by using the push buttons on the
front plate or via serial interface RS485. The assignment of the output relays is similar to the setting
of parameters:
•By pressing push button <SELECT/RESET> in blocking mode again, the assignment mode
is selected.

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Definition:
Alarm relays are activated at pickup.
Tripping relays are only activated after elapse of the tripping delay.
The relays are assigned as follows:
•LEDs P>, P< and Pr are two-colored and light up green when the output relays are
assigned as alarm relays and red as tripping relays.
•After the assignment mode has been activated, first LED P> lights up green. Now one or
several of the four output relays can be assigned to power element P> as alarm relays.
•Indication "1_ _ _" means that output relay 1 is assigned to this power element. When the
display shows "_ _ _ _", no alarm relay is assigned to this power element.
•The assignment of output relays 1 - 4 to the power elements can be changed by pressing
<+> and <-> push buttons.
•The selected assignment can be stored by pressing push button <ENTER> and
subsequent input of the password.
•By pressing push button <SELECT/RESET>, LED I> lights up red. The output relays can
now be assigned to this power element as tripping re-lays. Relays 1 - 4 are selected in the
same way as described before.
•By repeatedly pressing of the <SELECT/RESET> push button and assignment of the
relays all elements can be assigned separately to the relays.
The blocking and assignment mode can be terminated at any time by pressing the
<SELECT/RESET> push button for some time (abt. 3 s).
Note:
•The function of jumper J2 described in general description "MR Digital Multifunctional
Relays" has no function. For relays without assignment mode this jumper is used for
parameter setting of alarm relays (activation at pickup or trip-ping).
•A form is attached to this description where the setting requested by the customer can be
filled-in. This form is prepared for telefax transmission and can be used for your own
reference as well as for telephone queries.
Relay function Output relays Display- Lighted LED
1 2 3 4 indication
P> alarm X _ 2 _ _ P>: green
tripping X 1 _ _ _ P>: red
P< alarm X _ 2 _ _ P<: green
tripping X 1 _ _ _ P<: red
Pr alarm X _ _ 3 _ Pr: green
tripping X 1 _ _ _ Pr: red
U<P
r
alarm X _ _ 3 _ U<P
r
: green
tripping X 1 _ _ _ U<P
r
: red
tCBFP tripping X _ _ _ 4
Table 5.4: Example of assignment matrix of the output relay (default settings).

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5.3 Indication of measuring values and fault data
5.3.1 Indication of measuring values
During normal service, the following measuring values of the MRP2-3 can be indicated:
•Total three-phase active power (LEDs L1, L2, L3 green)
•Active power in phase L1 (LED L1 green)
•Active power in phase L2 (LED L2 green)
•Active power in phase L3 (LED L3 green)
In star-connection only:
•Phase-to-neutral voltage in phase L1 (LED U and L1 green)
•Phase-to-neutral voltage in phase L2 (LED U and L2 green)
•Phase-to-neutral voltage in phase L3 (LED U and L3 green)
In delta-connection only:
•Phase-to-phase voltage U12 (LED U, L1, L2 green)
•Phase-to-phase voltage U23 (LED U, L2, L3 green)
•Phase-to-phase voltage U31 (LED U, L1,L3 green)
Phase currents:
•Current in phase 1 (LED I and L1 green)
•Current in phase 2 (LED I and L2 green)
•Current in phase 3 (LED I and L3 green)
The following measuring values of the MRP2-1 can be indicated during normal service:
•Total three-phase active power (LED P green)
In star connection:
•phase-to-neutral voltage (LED U green)
In delta connection:
•phase-to-phase voltage (LED U green)
•phase current (LED I green)
5.3.2 Indication of fault data
All faults detected by the relay are indicated on the front plate optically. For this purpose, the four
LEDs (L1, L2, L3, →←) and the four function LEDs (P>, P<, Pr, U<Pr) are equipped at MRP2 and
MRP2-R1. If, for example a reverse power occurs, first the LEDs L1, L2, L3 will light up. LED Pr
lights up at the same time. After tripping the LEDs are lit permanently.
At unit MRP2-1 and MRP2-R1 the two LEDs (P, →←) and the four functional LEDs (P>, P<, Pr,
U<Pr) are equipped to display the detected fault data.