EAAM057608EN
GC250 Technical Manual 93
Parameter
Description
Default value
Voltage (Volt)
P.0102
Rated voltage
400 V
400
P.0226
Stopped engine threshold due
to voltage
17.5 %
70
P.0227
Started engine threshold due
to voltage
20.0 %
80
P.0301
Minimum voltage threshold
75.0 %
300
P.0303
Maximum voltage threshold
112.5 %
450
P.0202
Hysteresis
2.5 %
10
To the two settable thresholds (P.0301 and P.0303) the hysteresis is entirely applied in the
threshold input direction. This means that generator voltage is out of the tolerance if out of the
thresholds P.0301 and P.0303; it is in tolerance if between P.0301 + hysteresis and P.0303
–
hysteresis; otherwise, the previous status is maintained.
Keeping in account these values, the following bands are defined:
0
V
.
Band A:
Absent
70
V
.
Band B: Hysteresis
80
V
.
Band C:
Low
300
V
.
D band: Hysteresis
310 (300+10) V
.
Band E:
In tolerance
440 (450-10) V
.
Band F: Hysteresis
450
V
.
Band G:
High
xxx
V
.
If the voltage is in the “B”,”D” or ”F” bands, previous status is maintained (hysteresis). For
example, if the voltage was in the “E” band and now it is in “D” band, it is considered however
“In tolerance”. On the other hand, if it was in “C” band and now is in “D” band, it is considered
“Low”.
Such statuses are managed for each phase. With a three-phase system, in order to diagnose
the generator “global” status, the following algorithms are used, shown in the order they are
computed:
In case all the three phases are in “Absent” status, global status is also “Absent”.
In case all the three phases are in “In tolerance” status, global status is also “In
tolerance”.
In case at least one phase is in “High” status, global status is also “High”.
In case none of the previous conditions occurs, global status is “Low”.
Thresholds P.0301 and P.0303 are used also to manage the generator protections on voltage.
These protections can be individually disabled setting to zero the relevant parameter that
specifies the delay (respectively P.0302 and P.0304). Thresholds are however used in order
to define voltage status: this allows not to switch the loads on the generator if the electrical
magnitudes are out of the tolerance band, even though protections are disabled.
9.3.3
Generator status.
For general management purposes, generator can be in three conditions:
