|Error No.||Explanation||Corrective measures|
|6457||Capacitor self-test has failed.||Below - or Contact SoS|
Capacitor Self-Test Failed
90% of the time this is caused by a failing AC CT and not a capacitor failure. The test uses the AC currents and tests each time the inverter switches from online to offline. This is why the fault typically appears when the inverter is cycling in the mornings or evenings.
Capacitors can be removed and individually tested phase to phase. Be sure to calculate based on the capacitor rating which is posted on the sticker. Example calculation on a 100µF capacitor:
You should measure 150 µF between each of the phases.
Logic: Cap A + Caps A+B
|Example test point visual to show the series/parallel relationship|
If the capacitors are verified to be intact without issues, you can consider disabling the parameter CapTstEna by setting it to "OFF" temporarily. This test should ONLY be set to "LIGHT". SoS is not aware of SMA ever completing the functionality of the "FULL" test. This parameter is completely option and operators may set it to their preference. Be sure to check the electrical integrity and perform a visual inspection.
|Location of capacitors, label, and example of how to connect leads for testing capacitance|
|Photo describing some things to check for during a visual inspection|
Example of how a CT failure has caused a 6457 fault:
On 6/15 the L1 phase CT had a sudden change in its reporting where it began to lag the other two CTs. That evening is when the 6457 capacitor test failure alarms began to manifest. Most of the time this 6457 alarm appears due to a failing CT since the CTs are used to evaluate the integrity of the capacitors. If the capacitors have already been disconnected and verified, this information combined with the data suggests that the CT is very likely the reason for the failure.
This plot shows the sudden drop in CT reporting on L1 (the green and red lines) which are now showing 20-30A lower than the other CTs:
|The plot above displays a sudden drop in CT reporting on L1 (the green and red lines) which are now showing 20-30A lower than the other CTs|
|The image above shows the alarms beginning on the evening of when the fault manifests in the AC currents|