ABB eVM1 Installation And Service Instructions Manual page 66

C1: The start condition is
False for phases a, b,
and c.
C2: The start condition is
True for at least one
phase.
C3: The start-drop off
condition is True for all
the phases.
C4: The start condition is
True and t< Trip for at
least one phase.
C5: The condition of start
persistency is True
and t< Trip for at least
one phase.
C6: The condition of start
persistency is True
and t> Trip for at least
one phase.
C7: The condition of trip
persistency is True for
at least one phase.
C8: The trip drop-off con-
dition is True for all the
phases.
C9: The logic state Block
input is active.
64
When a protection is ticked it is enabled and the relative setting button is active; the protection
parameters setting window will be opened by clicking the setting button.
The parameters can be modified and a check of their ranges is made before applying the new
values.
14.7.1 General Protection Machine State
The machine state for a generic protection is shown in the figure below.
BEGIN
C: Trip exit (C8), (C9)
A: Reset all the protection
variabels
TRIP
C: Trip (C7)
A:
Fig. 56 General Protection Machine State
When the block input is passive and the measured current exceeds the setting threshold value
(Start Value), and pick-up value, the protection function is started. If the value of at least one
phase current is above the setting threshold value then the relative start signal will be activated.
The protection function will remain in START status until there is at least one phase started. It will
return to passive status and the start signal will be cleared when the block input becomes active
or at drop-off value, if the current falls below 95% the set threshold value for all the phases.
C: Protection activated
A: Reset all the protection
variabels
PASSIVE
C: Start reset (C3)
A: Reset protection counter
A: Reset the output start
C: Trip initiated (C6)
A: Set protection tripping
state
C: Protection activated (C1),
(C9)
A:
C: Start detected
A: Start protection counter
A: Set the output start
START
C: Start persistent (C4), (C5)
A: Wait protection counter to
expire