EAAM057608EN
GC250 Technical Manual 89
Such statuses are managed for each phase.
9.2.1.3
Mains voltage asymmetry control
In three-phase systems, the mains can be 'out of tolerance' in case the absolute value of the
three phase-to-phase voltages differs more than the set threshold.
To disable this check, simply set parameter P.0238 to zero.
Here follows an example about the various threshold used, including default values for a.m.
parameters:
Parameter
Description
Default value
Voltage (Volt)
P.0116
Rated voltage
400 V
400
P.0238
Mains asymmetry threshold
10.0 %
40
In case the absolute value of two phase-to-phase voltages differs more than 40 V, the mains
is seen as out of tolerance. In case the absolute values of all phase-to-phase voltages are
lower than 40 V, the mains is seen in tolerance. No hysteresis is managed for this check.
9.2.1.4
Rotation direction check
For three-phases systems, mains can be 'out of tolerance' in case the rotation direction of the
phases differs from the specification set with parameter P.0239
“Phases frequency required
on mains“. To disable this check, simply set parameter P.0239 to zero.
In case a “clockwise” rotation direction is required, please set “1” in P.0239; in case the rotation
direction is “counter-clockwise”, the mains is seen as “Out of tolerance”.
In case a “clockwise” rotation direction is required, please set “2” in P.0239; in case the rotation
direction is “counter-clockwise”, the mains is seen as “Out of tolerance”.
9.2.1.5
Internal mains sensor status
In order to diagnose the mains “global” status, the following algorithms are used, shown in
their computing order:
In case the status of all existing voltages (1 or 3)
and
the frequency are “Absent”,
also the global status is “Absent”.
In case the status of all existing voltages (1 or 3)
and
the frequency is “In tolerance”,
also the global st
atus is “In tolerance”.
In case the status of at least one voltage
or
the frequency
is “High”, also the global
status is “High”.
In case none of the previous conditions occurs, global status is “Low”.
In case the tests show that the mains is “In tolerance”, perform also the following tests:
If we have an unusually high asymmetry on the vo
ltages, the global status is “Low”.
If the direction of rotation of the mains is different from the one configured, the global
status is “Low”.
9.2.2
External mains sensor.
The use of a digital input is provided, configured with the function DIF.3101 -
“Sensor of
external mains”, for the connection with a generic mains sensor in alternative, or in addition to
the internal sensor.
To use the external sensor and deactivate the internal one, it is
necessary to put the rated mains voltage P.0116 to zero.
