ABB Relion 670 Series Technical Reference Manual page 615

1MRK505222-UUS C
Technical reference manual
prolongs the presence of MCBOP signal to prevent the unwanted operation of voltage
dependent function due to non simultaneous closing of the main contacts of the
miniature circuit breaker.
The input signal 89b is supposed to be connected via a terminal binary input to the
N.C. auxiliary contact of the line disconnector. The 89b signal sets the output signal
BLKV in order to block the voltage related functions when the line disconnector is
open. The impedance protection function does not have to be affected since there will
be no line currents that can cause malfunction of the distance protection.
The output signals 3PH, BLKV and BLKZ as well as the signals DLD1PH and
DLD3PH from dead line detections are blocked if any of the following conditions occur:
• The operation mode selector OpMode is set to Disabled
• The input BLOCK is activated
• The input BLKTRIP is activated at the same time as no fuse failure indication is
present
• The IED is in TEST status (TEST-ACTIVE is high) and the function has been
blocked from the HMI (BlockFUSE=Yes)
The input BLOCK is a general purpose blocking signal of the fuse failure supervision
function. It can be connected to a binary input of the IED in order to receive a block
command from external devices or can be software connected to other internal
functions of the IED. Through OR gate it can be connected to both binary inputs and
internal function outputs.
The input BLKTRIP is intended to be connected to the trip output of any of the
protection functions included in the IED and/or trip from external equipments via
binary inputs. When activated for more than 20 ms without any fuse fail detected, the
operation of the fuse failure is blocked during a fixed time of 100 ms. The aim is to
increase the security against unwanted operations during the opening of the breaker,
which might cause unbalance conditions for which the fuse failure might operate.
Secondary system supervision
Section 11
609