Pepco, the electric utility that serves Washington, D.C., and its Maryland suburbs, will spend $256.5 million over the next five years to accelerate planned improvements to its distribution system after it struggled to recover from a severe thunderstorm in late July.

More than 322,000 Pepco customers lost power after the storm; the company took five days to restore the power. The utility added $115 million to a planned system reliability upgrade after executives were grilled by the Maryland Public Service Commission about their response to the July storm and back-to-back snowstorms in February. Earlier this month, Pepco asked state regulators to approve a rate hike to cover the added improvements and schedule acceleration.

The July storm tore down 1,953 wires on Pepco’s distribution system, damaged 42 transmission lines and knocked out four substations and 214 distribution circuits, the company says. Pepco replaced 43 miles of cable, 83 wooden poles, 651 cross arms and 127 transformers.

The accelerated upgrade program’s largest expenditure will be $75 million to move certain overhead feeder lines and underground substations. No funds had been in the previous budget to do that, Pepco officials say. The company also will spend $37.5 million on a program to bury residential distribution lines.

Pepco will more than double its existing budget to install advanced control systems across the distribution system to identify faults and automate the switching mechanism; also, it will spend $15 million on automation. “These technologies will automatically isolate the failed pieces of equipment and restore most of the affected customers within minutes of the failure,” the company says. Pepco will use a portion of a U.S. Energy Dept. “smart-grid” grant to fund the upgrades.