On the D510 AVR, the LVRT function manage an automatic switching of the PF regulation to the voltage regulation when the voltage level is below 90% of the rated voltage.
Activate the voltage regulation allows to support the grid by providing reactive current effecitively the AVR increase the excitation current to recover the rated volatge and by the way , the genrator provide more reactive current.
- Check if the grid code function is enabled on the AVR or not (see picture below)
- Check that during the fault the grid voltage level is lower than the 90% of the rated voltage regulation value, corresponding to the threshold value from which the grid code function acts. The rated voltage regulation value must be adjusted at the nominal grid voltage to work properly.
Note: LVRT = Low voltage ride through