(Reuters) - A large fire in an electrical substation shut Royal Dutch Shell Plc’s 227,586-barrel-per-day (bpd) Convent, Louisiana, refinery on Tuesday night, said sources familiar with plant operations.

No injuries were reported due to the blaze, which broke out at about 8 p.m. CDT Tuesday (0100 GMT Wednesday), according to a Shell statement posted on-line.

The only units still operating at the refinery were the plant’s boilers, the sources said.

The refinery was scheduled to begin a planned overhaul next week on its 45,000 bpd heavy-oil hydrocracker, called the H-Oil Unit, the sources said. The work will shut half the unit’s production for up to a month. It was unclear on Tuesday if the plant-wide shutdown would affect the timing of the work.

The fire broke out on a substation operated by Entergy Corp that supplies the main power to the refinery, local media reported.

This is the second fire this year at the Convent refinery and the third since Aug. 11 2016. The two previous blazes were on the H-Oil Unit. The second fire was on March 18, 2017.

Shell took over sole ownership of the Convent refinery on May 1, 2017 when it and Saudi Aramco ended a nearly 20-year refining partnership.