ABB RELION SMU615 Technical Manual page 156

Supervision functions
The fuse failure detection outputs FUSEF_U and FUSEF_3PH are controlled
according to the detection criteria or external signals.
Table 183: Fuse failure output control
Fuse failure detection criterion
Negative-sequence criterion
Current and voltage delta function
criterion
External fuse failure detection
156
It is recommended to always set
that the blocked protection functions remain blocked until normal
voltage conditions are restored if the fuse failure has been active for
5 seconds, that is, the fuse failure outputs are deactivated when the
normal voltage conditions are restored.
Conditions and function response
If a fuse failure is detected based on the negative se-
quence criterion, the
FUSEF_U
If the fuse failure detection is active for more than five
seconds and at the same time all the phase voltage
values are below the set value of the
Enable seal in turned to "True", the function
ting with
activates the
FUSE_3PH
The output signal is also activated if all the
FUSEF_U
phase voltages are above the
for more than 60 seconds and at the same time the
negative sequence voltage is above
Lev for more than 5 seconds, all the phase currents are
Current dead Lin Val setting and the circuit
below the
breaker is closed, that is,
If the current and voltage delta criterion detects a fuse
failure condition, but all the voltages are not below the
Seal in voltage setting, only the
activated.
If the fuse failure detection is active for more than five
seconds and at the same time all the phase voltage
values are below the set value of the
ting with Enable seal in turned to "True", the function
activates the
FUSE_3PH
The input signal is supposed to be con-
MINCB_OPEN
nected through a merging unit binary input to the
N.C. auxiliary contact of the miniature circuit breaker
protecting the VT secondary circuit.The
signal sets the
FUSEF_U
the voltage-related functions when MCB is in the open
state.
The input signal is supposed to be
DISCON_OPEN
connected through a merging unit binary input to the
N.C. auxiliary contact of the line disconnector.The
signal sets the
CON_OPEN
block the voltage- related functions when the line dis-
connector is in the open state.
Enable seal in to "True". This secures
1MRS758407 C
output is activated.
Seal in voltage set-
output signal.
Seal in voltage setting
Neg Seq voltage
is TRUE.
CB_CLOSED
output is
FUSEF_U
Seal in voltage set-
output signal.
MINCB_OPEN
output signal to block all
output signal to
FUSEF_U
SMU615
Technical Manual
DIS-