President Carter scored a more than 2-to-1 victory over Sen. Edward M. Kennedy, and Ronald Reagan swamped George Bush in Louisana's first presidential primary today.

With 92 percent of the Democratic vote counted, the president had received 178,022 votes, or 55 percent, to Kennedy's 72,014, or 22 percent. With 91 percent of the Republican votes counted, Reagan had received 28,970 or 74 percent, and Bush, his closest opponent, had received only 7,551, or 19 percent.

Because Reagan carried every congressional district and no other GOP candidate got anywhere near 25 percent of the statewide vote, Reagan will get all 31 of Louisana's GOP convention delegates.

The Democrats are awarding their delegates on a proportional basis in each of the state's eight congressional districts. Consequently, the delegate lineup is not so easy to predict, but Val Marmillion, state coordinator for the Carter campaign, said Kennedy probably would get eight delegates, one per district, with the rest of the 51 Democratic delegates going to Carter.

As expected, voter turnout today was light -- barely 20 percent of the state's 2 million registered voters -- as six Democrats and six Republicans vied for delegates to their parties' national nominating conventions.

Even though today's election was part of the presidential selection process, only two candidates -- Reagan and Bush -- visited the state. The others stayed out of Louisana entirely or sent surrogates, preferring to work states with richer delegate prizes.

Because of this and the long Easter holiday weekend, Secretary of State James H. Brown Jr., whose office runs elections, had predicted that only about 25 percent to 30 percent -- 500,000 to 600,000 people -- would express their presidential preference and vote to fill local and state offices also on the ballot.

Because of the apathy toward the primary, several political observers have said that it may be scrapped. That decision will be up to the legislature, which convenes later this month.

Even though he did not come to Louisana, Carter relied on Louisanans' allegiance to a fellow southerner -- he carried the state in 1976 -- and on strong local support in today's contest. Among Louisanans backing the president are former governor Edwin W. Edwards; Housing and Urban Development Secretary, Moon Landrieu, who is New Orleans' former mayor; Rep. Lindy Boggs (D-La.), who was hostess to Rosalynn Carter during her brief visit here Friday; and New Orleans Mayor Ernest N. Morial.

Patrick Caddell, the president's pollster, predicted Carter would win 60 percent of the votes over Massachusetts' Sen. Kennedy. California Gov. Edmund G. (Jerry) Brown Jr. dropped out of the race this week after losing primaries in Wisconsin and Kansas, but his name was on the ballot, along with the name of four comparative unknowns.

Neither Reagan nor his camp had predicted his victory margin, but the former California governor, who received 36 of the state's 41 delegate votes at the 1976 Republican convention, expected to win big.

During his two-day swing through the state this week, he received an important promise from Gov. David C. Treen, who last month became Louisana's first GOP governor in 103 years.

Treen had urged his fellow Republicans to vote for uncommitted delegates today, but he told Reagan he would campaign for him if Reagan wins the party's nomination.

While in Louisana, Reagan repeated his basic message to loudly approving audiences: Cut taxes, cut spending, cut bureaucracy and cut restrictions that inhibit business.

Bush also spent two days in Louisana. During a news conference here, the former congressman, CIA director, amabassador and party chairman said the United States should sever diplomatic relations with Iran, set up a tough economic embargo against that country with the help of allies, close the Iranian Embassy in Washington, stop the influx of Iranians and deport Iranians who are here illegally.

Bush, Reagan and perennial candidate Harold Stassen were the only Republicans with any broad name recognition on the GOP ballot.

Of Louisana's 2 million registered voters, about 110,000 are Republicans. No crossover voting was allowed in the primary.

The delegate section processes differ for the two parties, although both are based on the state's eight congressional districts.

The Republican who wins in a congressional district collects all three delegates there. After those 24 delegates are allotted, the remaining seven are distributed proportionally among candidates who receive at least 25 percent of the statewide vote.

Thirty-five of the Democratic delegates will be allotted in proportion to the number of votes candidates receive in each district. The party's State Central Committee will pick the remaining 16, also to be distributed among candidates according to the results of today's voting, with an eye toward getting women and minority group members into the convention delegation. t