Installing hybrid PV-diesel system using Huawei inverters with a diesel generator and Encombi hybrid controller.
5KTL-M0 and 15KTL-M0 are connected in Daisy chain with RS485 communication cable and the hybrid controller is connected through RS485 communication to the master inverter which is the 15KTL-M0.
After the commissioning the inverters went to standby mode and no alarms were raised.
Step 1 – Verifying the system connection and design parameters of Huawei inverters
First of all, I have measured the DC voltage and Isc current of the strings as well as the AC phases voltage which were in the operating voltage range.
Secondly, I have updated the firmware of the inverters as per the latest upgrades as many of the generation issues can be related to inverters firmwares not being updated.
Step 2– Investigating inverter and hybrid controller connection
I have investigated the RS485 communication scheme between the inverters and the hybrid controller to eliminate the chances of communication errors.
The load consumption was 7KW, the the inverters output power was set to 2KW in total by the hybrid controller. But the inverter was still in standby mode so the total power was being supplied by the generator
I have investigated the voltage and frequency range of both the inverter and generator, I noticed that the generator frequency value is 51.5 Hz and the inverter’s over frequency de-rating function under the power adjustment options was enabled with a trigger frequency set to 50.3 Hz, therefore the inverters were not able to synchronize with the generator’s frequency range and remained in standby mode
Once the function was disabled, the inverters were able to match with the generator frequency and exit from the standby mode into the operation mode to generate limited power as per the command from the hybrid controller.
