
Woodward
Manual MRI3 GB
36
DOK-TD-MRI3 Rev.A
5.4.17 SOLI/RESI changeover (SR/YR-relay type)
Depending on the method of neutral-point connection of the system to be protected, the directional
element for the earth-current circuit must be set to "SOLI" (= solidly earthed) or "RESI" = (resis-
tance earthed).
5.4.18 Block/Trip – time
The block/trip time serves for detection of a c.b. failure protection by rear interlocking. It is activated
by setting the blocking input D8/E8 and by setting the parameter to TR_B. After the set block/trip
time has expired, the relay can be tripped if the excitation of a protective function has been applied
the delay time of which has expired and the blocking function is still active. If the parameter PR_B
is set, the individual protection stages are blocked (refer to Chapter 5.7.1).
5.4.19 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 I
N
within t
CBFP
(Circuit Breaker Failure Protection - adjustable between 0.1 -
2.0 s). If not all of the phase currents have dropped to <1%xIN within this time, CB failure is de-
tected and the related relay activated. The CB failure protection function is deactivated again as
soon as the phase currents have dropped to <1% x I
N
within t
CBFP
5.4.20 Adjustment of the slave address
Pressing push buttons <+> and <-> the slave address can be set in the range of 1-32.
5.4.21 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>.
5.4.22 Setting of parity (applies for Modbus Protocol only)
The following three parity settings are possible :
• "even"
=
even
• "odd"
=
odd
•
"no"
= no parity check
The setting can be changed by push buttons <+> and <-> and saved by pressing <ENTER>.