When L. Douglas Wilder was elected lieutenant governor of Virginia on Nov. 5, the outcome was widely cited as evidence of black political progress in this country. But two other elections that day could foreshadow a change in voting patterns that could be as significant to blacks as Wilder's victory.

New Jersey Gov. Thomas H. Kean (R) was reelected with 60 percent of the black vote, improving his performance with blacks sixfold over 1981. Meanwhile, Cleveland Mayor George V. Voinovich, another moderate Republican, won a third term with more than 80 percent of the black vote.

Off-year elections are not necessarily reliable in predicting changes in voting behavior, and the Kean and Voinovich elections are not the first in which Republicans have received a majority of the black vote. In 1978, Richard L. Thornburgh (R) was elected governor of Pennsylvania with about 60 percent of the black vote, and four years ago Voinovich won his second term with an equally strong showing among blacks as on Nov. 5.

But at a time of continued black criticism of the Democratic Party and its leadership and talk of a possible independent black candidacy for president in 1988, signs of independence among blacks are being looked at with renewed interest.

Some political observers argue that the New Jersey and Cleveland elections indicate that blacks may be going through the "de-alignment" other voting groups have shown in recent years -- particularly young, upwardly mobile professionals and especially in state and local politics.

"The people who are changing over now are people who think quite a bit about issues . . . and see that whatever their opinions are, they can be better expressed through the Republican Party," said New Jersey Energy Commissioner Leonard S. Coleman Jr., 36, a lifelong Republican. "You find a changeover with black young people who have been frustrated with getting into the mainstream of the Democratic Party."

No one is predicting a sudden or dramatic reversal in voting patterns among blacks, who have been the Democrats' most loyal voting bloc for more than two decades.

But Linda F. Williams, senior research associate at the Joint Center for Political Studies here, noted that in a survey of more than 900 blacks last year, those under age 30 were about half as likely to call themselves "strong Democrats" as were those over age 30.

Williams suggested that a moderate Republican presidential nominee could win as much as 30 percent of the black vote in 1988. That would be three times as much as President Reagan received last year and more than any other GOP nominee since Richard M. Nixon's unsuccessful presidential campaign in 1960.

"There has been no candidate identified except [religious broadcaster] Pat Robertson that blacks have the same antipathy for as Ronald Reagan," Williams said of the field of potential 1988 GOP nominees. "Democrats would have to have a very strong candidate" to prevent a moderate Republican from "siphoning off a large part of the black vote."

Democrats have received between 85 percent and 90 percent of the black vote in every presidential election since 1964. In 17 states containing 221 of the nation's 538 electoral votes, the black proportion of the voting-age population is sufficient to provide the margin of victory.

The way Kean and Voinovich won black majorities is far from new. The two Republicans addressed much of the "black agenda" on which Democrats have delivered for years -- administrative and judicial appointments, minority contracting, educational and social programs and racial sensitivity.

Moderates like Voinovich and Kean also have begun to change the perception of the GOP in some communities by taking advantage of the climate of certain state and local elections where personality can play a more important role than partisanship or ideology.

"The Republican Party in New Jersey has posed its own image," Coleman said. "We've got our own New Jersey identity in regards to issues with the black community."

New Jersey was once strongly Democratic. Now independents are the largest group of registered voters and nearly as many people identify themselves as Republicans as Democrats. Alan Rosenthal, director of the Eagleton Institute of Politics at Rutgers University, said he was uncertain, however, if blacks were a part of that trend. The state GOP is largely a suburban organization, while most blacks live in the cities, Rosenthal said.

Most of the 14 seats in the state Assembly that Republicans picked up on the strength of Kean's coattails Nov. 5 were in suburban areas, and all four blacks running under the GOP banner lost.

"The expectation level of blacks with Tom Kean and the Republican Party is very, very high," Coleman said. But "before this election can be considered any kind of watershed, the process on the Republican side has got to be institutionalized."

Coleman, echoing the view of C. Delores Tucker, chairman of the Black Caucus of the Democratic National Committee, said the Kean vote should make Democrats more competitive for black votes.

New Jersey Democratic Chairman Ray Durkin said, however, that while he is concerned about blacks voting Republican, "the whole vote was a tribute to Kean's terrific personal popularity. My feeling is it's not a defection to Republicanism as much as it is to Tom Kean."

In Ohio, Voinovich's ability to win reelection so easily in Cleveland has made him the choice of some Republicans to challenge Gov. Richard F. Celeste (D) next year. So far, Voinovich has left the challenge to ex-governor James Rhodes (R).

The mayor is not the city's only GOP success story. Virgil E. Brown, a black Republican, has been county commissioner since 1979. Brown has been elected and reelected with little if any public political support from the city's major black leaders, all of whom are Democrats.