Virginia Gov. Charles S. Robb held himself and his 18-month-old administration today as a model of enlightenment in the New South and pledged to work with the NAACP toward achieving the kind of nation envisioned by Abraham Lincoln.

Speaking unlike many of his precedecessors in Richmond, Robb urged increased voter registration by blacks, called expanded minority enterprise a necessity for the American economy and linked Virginia's future to the progress of its black residents.

"For the government of a southern state to commit its resources, its energies and hope for the future . . . to its black citizens," Robb exclaimed, "We've come a long way, baby."

NAACP convention organizers had invited Robb to showcase black progress in the state. "The state of Virginia has made some significant breakthroughs in terms of access and using blacks," said Althea Simmons, director of the organization's Washington office. "We are hoping that our branch people will go back to their home communities and get the governors to do the same thing."

And people like Jack W. Gravely, Virginia State director of the NAACP and a Robb adviser, were all too happy to trot the governor out. Never mind that his rigid speaking style couldn't match the animated oratory of the next speaker, former Florida governor Reubin Askew, a Democratic presidential candidate, and not to mention the booming Baptist oratory that followed both.

"Let's face it," Gravely said. "In the political arena, Chuck Robb has sex appeal, and he just happens to be the governor of Virginia and I just happen to be the state director of the NAACP and we just happened to go to law school together."

"Young governor," Gravely mused, ticking off Robb's pluses, "not liberal but a progressive governor and he's done a few things in the state of Virginia that some of us feel are noteworthy. We thought this was a golden opportunity for the governor of Virginia to express himself and his policies to a cross-sections of Afro-Americans."

Robb has appointed the first black State Supreme Court judge, the first black chairman of the state parole board, the first blacks to serve on the state Alcoholic Beverage Control Commission and other agency boards. He appointed six blacks to head state agencies, chose a black woman as commissioner of commerce and industry and overall selected blacks for 175 or his first 1,307 board and commission appointments.

Robb did not repeatedly criticize the Reagan administration, a silence that cost him applause in an audience where anti-Reagan sentiment appears to run high.

Yet when asked to rate Robb's speech, Gravely gave the governor "an 8 1/2 or 9" on a scale of 10. "Anyone can rant and rave about Reagan," Gravely said.

NAACP national vice president Kelly M. Alexander Sr. of Charlotte, N.C., was more generous. Declaring that the day's opening session had gotten off on a high note with Robb's speech, Alexander said: "If that governor means what he says, Virginia is going to be a great place to work and live in."