WARNING/ALARM 302, Cap. over current
Excessive current was detected through the AC capacitors
of the LCL filter.
See for current trip points.
Troubleshooting
•
Check that the nominal voltage parameter
(300-10) is set correctly. If the nominal voltage
parameter is set to Auto, change this parameter
to nominal voltage of the installation.
•
Check that the CT parameter placement
(parameter 300-26) corresponds to the installation
•
Perform the Line Power Resonance Test (
)
WARNING/ALARM 303, Car. earth fault
A ground fault was detected in the LCL filter AC capacitor
currents. The summed currents in the LCL filter CTs
exceeds the power unit dependent (PUD) level.
Troubleshooting:
•
Turn off the filter
•
Measure the resistance to ground of the LCL filter
components leads with a megohmmeter to check
for ground faults
•
Check the AC capacitors and current transducers
•
Check that the connectors on current transducers
and on the AFC card are pinned properly
•
Check AC capacitors current transducers cables
•
Replace the AFC card
WARNING/ALARM 304, DC over current
Excessive current through the DC link capacitor bank was
detected in the IGBT current sensors.
Troubleshooting
•
Check the electrical fuses and ensure that all
three line phases are powered.
•
Check that the CT parameter placement
(
300-26 CT Placement
) corresponds to the instal-
lation.
•
Perform the Line Power Resonance Test (
)
ALARM 305, Mains. freq. limit
The line power frequency was outside the limits (50 Hz–60
Hz) +/-10%. Verify that the line power frequency is within
product specification. The alarm may also indicate loss of
line power for 1 - 3 electrical cycles.
The active filter must synchronize to the AC line voltage in
order to regulate the DC link voltage and inject compen-
sating current. The active filter utilizes a phase-locked loop
(PLL) to track the AC line voltage frequency.
When the active filter starts, the PLL uses the LCL filter AC
capacitor currents from the current transducers to initialize
for a period of 200 ms. After the PLL initialization period,
the active filter inverter will then start switching, the line
power estimated voltage is used instead of the capacitor
currents as input to the PLL. The PLL is not tolerant of
incorrect wiring or placement of the AC capacitor current
transducers.
Troubleshooting:
•
Turn off the filter
•
Measure the resistance to ground of the LCL filter
components leads with a megohmmeter to check
for ground faults
•
Perform AC capacitors and current transducers
test (
•
Check that the connectors on current transducers
and on the AFC card are pinned properly
•
Check AC capacitors current transducers cables
•
Replace the AFC card
•
Automatic switching between the grid and a
generator based on certain events can cause line
power loss leading to this alarm. Use auto reset if
this is the cause.
ALARM 306, Compensation limit
The compensation current exceeds unit capability. Unit is
running at full compensation.
Warning 306 is informational in nature, and does not
indicate a malfunction.
WARNING/ALARM 308, Resistor temp
Excessive resistor heatsink temperature detected.
A temperature feedback is implemented using an NTC
thermistor mounted on the damping resistor heatsink. The
temperature is calculated and compared to a power unit
dependent (PUD) alarm level.
Warning 308 is displayed when the PUD warning level is
reached. This indicates the resistor temperature is close to
the alarm level.
Troubleshooting:
Verify if:
•
Ambient temperature is too high
•
Incorrect clearance above and below the unit
•
Dirty heatsink
•
Blocked air flow around the unit
•
Damaged heatsink fan
Troubleshooting
VLT Advanced Active Filter AAF006 D and E Frames Service Manual
4-10
MG90Z122 - VLT
®
is a registered Danfoss trademark
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