More than 17,000 homes across the region were without power from just before 6pm after two fires started at Horsham’s power substation.

The fires threatened two buildings and thick black smoke blanketed the area around the substation.

The Western Highway was closed from Osbourne Road to Golf Course Road in Horsham as Country Fire Authority crews carted water across the highway.

Two firefighters were taken to Wimmera Base Hospital for heat-related illness.

A Powercor spokeswoman said the fires started when the number one transformer failed.

“It could have been a bird flying over the line or anything,” she said.

“It depends how old the asset it. This doesn’t happen often, but it’s not uncommon.

“It’s just one of those things, especially going into bushfire season.

“We are always prepared for these sorts of issues when they arise and we have a crew on the ground.”

The spokeswoman said a Powercor crew was able to isolate the transformer once fire crews contained the blazes.

“We then rerouted customers to the remaining transformers to re-energise the line and get power back to customers,” she said.

“About half an hour after the fire was contained we managed to get about 3200 customers back online.

“By 10pm power had been restored to all customers.”

Country Fire Authority District 17 duty officer Ian Day said about 35 firefighters from Horsham and neighbouring areas fought the fire.

“The main difficulty was safety to personal,” he said.

“We weren't able to do anything with the fire until the power supply was isolated, and the power company got on top of that very quickly thank goodness.

“From from there the crews were able to extinguish fire quite successfully.”

Mr Day said it took about an hour to extinguish the fire once crews were able to access it.

“We did have to bring extra trucks in for water,” he said.

“We kept the fire from affecting the other two transformers, which allowed the power company to reinstate power earlier than a lot of people expected.”