The Texas-based Electronic Data Systems Corp. announced today it will build a new regional center on 202 acres in Fairfax County near Dulles International Airport, a project that state officials said would be one of the largest private employers in Northern Virginia.

"It is a coup of a large magnitude," boasted Fairfax County Executive J. Hamilton Lambert, referring to the intense competition among Washington jurisdictions for the lucrative computer and high-tech firms drawn to the area by the presence of the federal government.

Virginia Gov. Charles S. Robb was only slightly less subdued as he disclosed that the firm will bring as many as 3,000 jobs to the state, the largest single increase in jobs since the state began keeping records. "It's a very significant announcement," the governor told a news conference here.

EDS, which specializes in "soup to nuts" computer services for large firms and government agencies, was acquired late last year by General Motors Corp. at a cost of $2.5 billion, one of the largest acquisitions in the country's history.

Plans for the regional center, to be on Sully Road (Rte. 28), about two miles south of the Dulles Access Road, include 400,000 square feet of office space and a 75,000-square-foot data processing center, according to company officials.

A spokesman for the company, begun in the early 1960s by entrepreneur Ross Perot, declined to place an overall cost on the project.

State officials suggested that the project, at routine building costs of about $80 to $100 a square foot, would easily be in the $50 million range without the cost of acquiring the privately owned land, one of the largest undeveloped sites in Fairfax County. A county official said the land alone may cost about $30 million.

EDS officials said they also considered other sites, including ones in Fairfax's arch rival, Montgomery County, where many of the 2,000 EDS employes who are now in the Washington area work. Those workers and about 1,000 new EDS employes will be located at the Dulles site.

Penny Pasquesi, director of EDS public relations in Dallas, said today that in addition to workers at smaller regional headquarters in Bethesda, EDS has 250 employes at a computer center in the Newington section of Fairfax. Pasquesi said many of the company's employes already live in Northern Virginia and could not estimate how the center would affect housing and other increased demands for services.

EDS currently holds major contracts with such government agencies as the Department of Defense, Navy, Social Security administration and the Postal Service, Pasquesi said.

She said the company chose Fairfax because of its proximity to Washington and to Dulles. "Obviously the access to Dulles was one of the good considerations," she added.

Fairfax County Board Vice Chairman Martha V. Pennino, who represents the area, said the announcement confirms the belief of county officials that "Dulles is the coming area for industrial development." She cited the recent announcements that the state would locate its Center for Innovative Technology there and that a major computer software consortium would locate its headquarters nearby.

Pasquesi said neither Fairfax nor the state offered any special enticements to lure the company to Virginia. She said breaking ground for the project would probably begin in September and the building should be completed in June 1988.

The EDS plan, which state officials said will bring to 1,001 the number of high-tech operations based in Northern Virginia, is only the latest in a series of major corporate high-tech developments announced in the region, including projects by Xerox Corp. in Loudoun, International Business Machines Corp. in Prince William and TRW in Fairfax.

Last year, more than one-fourth of all new commercial construction in the Washington area was in Fairfax, proof of the county's determined campaign to develop a broad industrial base.

Asked about the regional competition, Robb said, "We obviously compete very hard," but declined to discuss the issue further because of the "good relationship" he said Virginia has with Maryland and the District of Columbia.

Virginia development officials said the project has been under consideration for more than three years.

Betty Diener, Virginia secretary of commerce and resources, hailed the project as a major accomplishment for the state's Department of Industrial Development, the centralized state agency that recruits businesses for the state and sponsors the governor's overseas trade missions.