The connection was restored approximately 40 minutes after the disconnection, the organization clarified.
The ultimate cause of the incident remains unknown, but the IAEA team stationed at the facility is conducting an investigation and monitoring the situation's development.
The loss of external power underscores the ongoing critical nuclear safety situation, Grossi emphasized.
The plant earlier lost external power supply on the morning of April 14, and it was restored that same day.
ZNPP lost connection to the 750 kV Dniprovska line, one of its two power lines, the IAEA reported on March 24. This left the ZNPP relying on a single backup 330 kV Ferosplavna-1 line.
The 330 kV Ferosplavna-1 backup power line was restored and reconnected to the occupied Zaporizhzhya Nuclear Power Plant following repair works conducted during an IAEA-brokered local ceasefire on March 5. The line remained disconnected for 23 days.
This followed an IAEA report from Feb. 27 stating that Ukraine and the Russia agreed to a local ceasefire in the Zaporizhzhya Nuclear Power Plant area to facilitate the necessary repair of backup power lines.
ZNPP was operating with only one external power line after losing a backup line, posing increased risks to nuclear safety, the International Atomic Energy Agency reported on Feb. 19.