Russian shelling damaged electricity distribution networks in five Ukrainian regions overnight, Ukraine's state grid operator said on Monday.
"The night attack by drones did not damage the main energy infrastructure," Ukrenergo said in a statement.
"However, due to Russian shelling along the frontline and border shelling, there is again damage to distribution networks in Donetsk, Kharkiv, Kherson, Sumy and Chernihiv regions."
Ukraine's energy system has survived months of Russian missile and drone attacks that have at times left millions without power or heating during the cold winter months.
But fast repairs, equipment supplied by Ukraine's Western partners and favourable weather for hydro-power stations have allowed Kyiv to restore power supplies and even start small electricity exports to neighbouring countries.
Electricity generation now fully covers consumption thanks to hydro-power stations and the seasonal increase in power production by solar and wind power plants, Ukrenergo said.
It also said that repair work continued actively across Ukraine, and that officials and the energy industry were committed to strengthening the heavily damaged system and preparing it for the next cold season.
