Nearly 4,000 Westar Energy customers lost power Wednesday afternoon after an electrical substation in southwest Lawrence sustained extensive damage, according to a utility spokeswoman.

The failure of a piece of equipment on a circuit at a substation caused the outage, Westar spokeswoman Karla Olson said.

The outage occurred at 2:55 p.m., and by 3:40 p.m., 1,200 customers had power restored, Olson said. Another 1,000 customers had power back by about 4 p.m. The remaining customers had power by 6 p.m., she said.

SuperTarget, 3201 Iowa, switched to a back-up generator, manager Ken Johnson said.

Power returned to the store after about an hour and 15 minutes, Johnson said.

Elaine Taylor, who lives in the area of Crossgate Drive and Clinton Parkway, said her power was out about an hour.

“I was glad it didn’t happen at night,” she said.