Pepco officials urged patience as they anticipate “widespread” and “multi-day” power outages from Hurricane Irene in the Washington region, where the company has 778,000 customers in the District and Montgomery and Prince George’s counties.

“This is a huge event,” said Joe Rigby, chief executive officer of Pepco’s parent company, Pepco Holdings. Rigby said the company has 150 out-of-state workers headed to the area to help a beefed up staff of about 815 of Pepco’s own employees and a pool of contractors who have been here for several months helping with tree trimming and repairs as part of a multi-million dollar plan to improve service. By Sunday, there should be a total of about 1,300 workers working on power restoration, Rigby said.

Sustained high winds will need to abate to less than 35 miles per hour before crews in bucket trucks can go to work on lines, due to workplace regulations on safety.

Rigby spoke along with other senior company officials at a press conference Friday at the company’s Control Center in Bethesda. Rigby said their presence at the microphones was an acknowledgment that the top brass felt it was important “to talk to you directly” after more than a year of withering criticism and ongoing reviews by utility regulators in Maryland and the District.

Rigby and Thomas Graham, Pepco Region president, said trimming and equipment upgrades completed this year have put the company in a better position to get power back on faster but there still will be major disruptions.

The executives also said that the call centers that respond to customers have double the capacity of a year ago. Likewise, the computer mapping on outages and repair status has been refined to show an area within 600 yards of a reported outage rather than a mile-away view that frustrated many customers during previous storms.

“This is a test and we intend to pass this test,” Rigby said, adding, “that will be in the eyes of the customer.”

Rigby also said he knew that whatever the improvements done on the power system, Pepco “still has a lot of work to do to reclaim Pepco’s brand.”

Pepco began making telephone robo-calls to 640,000 customers Friday to alert them to likely outages and asking them to prepare with emergency supplies from vital medicines to battery operated radios and alternative lighting sources. However, the company was not predicting how many customers it expected to be without power.

In response to a question, Rigby said that he does not own a home generator, an investment some homeowners have made after suffering extended outages during the past several years.

Graham said that he does have a backup generator for his Prince George’s County home.

The challenges posed by Hurricane Irene arrive as Pepco remains under investigation by Maryland state regulators for its subpar reliability compared with other electrical utilities and as the Maryland Public Service Commission separately designs performance standards for electrical companies statewide.

Maryland legislators passed a bill in April that imposes a $25,000-a-day fine on electric utilities for each violation of reliability standards. The standards are to be enforced by July 2013.

In July, District regulators tightened performance standards for Pepco, threatening to fine the beleaguered power company unless it improves reliability within two years and matches the performance of the nation’s most dependable power providers within a decade.

Also in July, Pepco applied for a 5.3 percent rate increase that would cost a typical District residential customer $5 a month and provide the company with an additional $42 million a year.

The push for higher reliability standards follows an investigation by The Washington Post that found Pepco ranked near the bottom nationally among electricity companies in terms of keeping the power on and bringing the lights back once the electricity goes out. The Post found that the average Pepco customer experienced 70 percent more outages than customers of other big-city utilities. And the lights stayed out, on average, more than twice as long.

The newspaper’s report concluded that Pepco’s reliability began faltering five years ago and that company officials failed to stem the decline. Reliability in Maryland was substantially worse than in the District, where many lines are underground.