Former State Del. Carrington Williams of Fairfax County today formally joined the field of five other Democrats seeking their party's nomination to the U.S. Senate this year.

Williams, 58, was a moderate-conservative member of the Virginia House of Delegates for 10 years and announced at the end of the last legislative session that he would not run for his seat again in order to seek the Senate nomination.

At his announcement press conference in the State Capitol, Williams described himself as "a conservative on fiscal issues and a moderate on other issues."

"I am running because I don't think the federal government has been giving the American people a fair shake," he said. "For almost two decades, we have been looking for easy answers to hard questions. Our government has spent money that it has not had and much of that money has been spent badly."

He added: "The days of pork barrel politics are fading. Well meaning liberalism and massive spending programs are falling into disfavor. People are beginning to see that government-promoted inflation is only a way of hiding the costs of these programs. It is an unseen tax that drains away people's hard-earned savings and ultimately creates recessions and unemployment."

Williams said in answer to questions that he does not favor the proposed Panama Canal Treaty in its present form, but wants additional guarantees for the U.S., including the right to seek construction of an alternate water-level canal.

He also said in answer to questions that he does not object to extension of the time period for ratification of the proposed Equal Rights Amendment so long as states that have ratified also have the chance to rescind their approval.

Williams was mildly critical of President Carter in response to questions, saying that the President has undertaken a legislative program that was too ambitious and has been unrealistic in promising to remove the politics from selection of U.S. attorneys.

Williams has been a taxation specialist in both public and private life. He is a tax lawyer for the large Northern Virginia law firm of Boothe, Prichard and Dudley. In the Assembly, he was a member of the tax legislation writing House Finance Committee and chairman of the State Revenue Resources Commission, an advisory committee of legislators, local officials and private citizens who draft taxation proposals for the Assembly.

Williams was born in Brookneal in the heart of Virginia's Southside tobacco country and is a graduate of Johns Hopkins University and the University of Virginia Law School.

Virginia's Democrats, after failing for the last 10 years to elect either a governor or U.S. senator, have decided to conserve party resources by nominating their Senate candidate at a convention next June. The Democrats usually hold a primary.

In addition to Williams, the announced candidates are former Attorney General Andrew P. Miller; Flora Crater, of Falls Church, a 1973 independent candidate for lieutenant governor; state Sen. Clive L. DuVal II of Fairfax, and former Fairfax Supervisors Fred Babson and Rufus Phillips.