MRI1- Digital multifunctional relay for overcurrent protection
3
Contents
1 Introduction and application
2
Features and characteristics
3 Design
3.1 Connections
3.1.1 Analog input circuits
3.1.2 Output relays of MRI1-relays
3.1.3 Blocking input
3.1.4 External reset input
3.2 Relay output contacts
3.2.1 Parameter settings
3.3 LEDs
4 Working principle
4.1 Analog circuits
4.2 Digital circuits
4.3 Directional feature
4.4 Earth fault protection
4.4.1 Generator stator earth fault protection
4.4.2 System earth fault protection
4.5 Earth-fault directional feature (ER relay
type)
4.6 Determining earth short-circuit fault
direction
4.7 Demand imposed on the main current
transformers
5 Operation and setting
5.1 Display
5.2 Setting procedure
5.2.1 Pickup current for phase overcurrent
element (I>)
5.2.2 Time current characteristics for phase
overcurrent element (CHAR I>)
5.2.3 Trip delay or time multiplier for phase
overcurrent element (t
I>
)
5.2.4 Reset setting for inverse time tripping
characteristics in the phase current path
5.2.5 Current setting for high set element (I>>)
5.2.6 Trip delay for high set element (t
I>>
)
5.2.7 Relay characteristic angle RCA
5.2.8 Voltage transformer connection for
residual voltage measuring
5.2.9 Pickup value for residual voltage U
E
(ER
relay type)
5.2.10 Pickup current for earth fault element (I
E>
)
5.2.11 WARN/TRIP changeover (E and ER relay
type)
5.2.12 Time current characteristics for earth fault
element (CHAR IE) (not for ER relay type)
5.2.13 Trip delay or time multiplier for earth fault
element (t
IE>>
)
5.2.14 Reset mode for inverse time tripping in
earth current path
5.2.15 Current setting for high set element of
earth fault supervision (I
E>>
)
5.2.16 Trip delay for high set element of earth
fault supervision (t
IE>>
)
5.2.17 COS/SIN Measurement (ER relay type)
5.2.18 SOLI/RESI changeover (SR-relay type)
5.2.19 Circuit breaker failure protection to CBFP
5.2.20 Nominal frequency
5.2.21 Display of the activation storage (FLSH/
NOFL)
5.2.22 Adjustment of the slave address
5.2.23 Blocking the protection functions and
assignment of the output relays
5.3 Setting value calculation
5.3.1 Definite time overcurrent element
5.3.2 Inverse time overcurrent element
5.4 Indication of measuring values
5.5 Reset
6 Relay testing and commissioning
6.1 Power-On
6.2 Testing the output relays and LEDs
6.3 Checking the set values
6.4 Secondary injection test
6.4.1 Test equipment
6.4.2 Example of test circuit for MRI1 relays
without directional feature
6.4.3 Checking the input circuits and measured
values
6.4.4 Checking the operating and resetting
values of the relay
6.4.5 Checking the relay operating time
6.4.6 Checking the high set element of the
relay
6.4.7 Example of a test circuit for MRI1 relay
with directional feature
6.4.8 Test circuit earth fault directional feature
6.4.9 Checking the external blocking and reset
functions
6.5 Primary injection test
6.6 Maintenance
7 Technical data
7.1 Measuring input circuits
7.2 Common data
7.3 Setting ranges and steps
7.3.1 Time overcurrent protection (I-Type)
7.3.2 Earth fault protection (SR-Type)
7.3.3 Earth fault protection (E-Type)
7.3.4 Earth fault protection (ER-Type)
7.3.5 Inverse time overcurrent protection relay
7.3.6 Direction unit for phase overcurrent relay
7.3.7 Determination of earth fault direction
(MRl1-ER)
7.3.8 Determination of earth fault direction
(MRl1-SR)
7.4 Inverse time characteristics
7.5 Output contacts
8 Order form