MC30-R2
Doc. N°
MO-0462-ING
Copyright 2012
FW: 1290.37.01.x
Date
06.09.2022
Rev.
1
Pag.
21
of
38
4. Logic Blocking of Functions
4.1 - Blocking Outputs
The instantaneous element of each of the protection functions (1F50, 2F50, 3F50, 1F50N, 2F50N, 3F50N)
can be programmed to control one of the Output Relays.
This relay picks-up as soon as the input quantity exceeds the set trip level of the Protection Function and it
automatically resets when the input quantity drops below the function reset level (
95% of the trip level) or,
in any case as soon as the time delay (tBF) of the Breaker Failure function is expired.
This instantaneous output can be used to activate the Blocking Input of another Protection Relay to
implement a logic selectivity systems. As above explained, in case of Breaker Failure, the blocking output is
released and the back-up protection enabled.
4.2
–
Blocking Inputs
The time delayed tripping of any of the Protection functions (1F51, 2F51, 3F51, 1F51N, 2F51N, 3F51N) can
be controlled by the activation of the Digital Input D1 (BI=Enable): in this case the set trip time delay of the
function is increased by “2xtBF” so that other Protection Relays (set with the same trip time delay) that send
the activation signal to the blocking Input D2, can trip before open and the C/B nearest to the Fault.
Also in this case, however, another “2xtBF” seconds from the expiry of the set trip time delay, the blocking
input is disregarded so allowing the protection relay to trip in case of Failure to open of the upstream Circuit
Breaker.
5. Output Relays
Four user programmable Output Relays are normally available R1, R2, R3, R4.
Each of them can be programmed to be controlled by any element (instantaneous or time delayed) of any of
the Relay Functions including Breaker Failure and Internal Relay Fault.
Each output relay can also be programmed to operate “
” and “
” control of the C/B either by the
Relay Keyboard or via the serial communication bus
Moreover, the operation of each of the output relays can be programmed to be either Normally Deenergized
(energized on tripping of the controlling Functional Element) or Normally Energized (Deenergized on tripping of
the controlling Functional Element).
As an option (to be required when ordering the relay), the output relay “
R4
” can be rep
laced by a Field Bus
output (CANBUS) that controls additional I/O modules for increasing as needed the number of user
programmable Output Relays and Digital Inputs controlled from the relay.
