One of President Carter's two closest aides, press secretary Jody Powell, is altering his role at the White House, but there appears to be little immediate prospect for other changes in the internal staff system that Carter has installed around himself.

Powell is gradually easing himself out of many of the day-to-day functions of a presidential press secretary to devote more time to planning long-range public relations strategy for the President and the administration as a whole.

The shift in Powell's role, and the fact that other aides see no evidence of an impending shakeup in the White House staff, are both based on the same judgment: that Carter's recent problems, the suggestions that the administration is not quite in control of itself, are more of a matter of public perception than signs of real internal weakness or disarray.

Powell first announced the change in his role in an interview two weeks ago with Newsday, the Long Island,N.Y., newspaper. In a statement much like the laments of aides to former President Ford, who used to blame themselves for not conveying to the public what they said was Ford's sure grasp of the presidency, Powell said in the interview:

"We have not presented in an understandable fashion what it all means. What the public has been seeing is a confusing welter of actions [bythe administration]. That is largely a shortcoming that addresses itself to this office and to me in particular. We have not done a good job of placing in context what the administration is really trying to do."

What the shift in Powell's role means, in practical terms, is that he is appearing less these days at the daily White House news briefing, turning an increasing number of these sessions over to his deputy, Rex Granum.

Instead, Powell has attempted to turn his attention to other matters. He wad deeply immersed in the preparation of the President's speech last week to the World Jewish Congress and the energy address on national television Tuesday night. He has also been involved in daily staff meetings at the White House aimed at coordinating the administration's efforts to win enactment of his energy legislation.

When Carter was asked at a news conference Oct. 27 about Republican charges that his administration is "inept," he responded with a lengthy discourse on his views of the presidency, remarking in the course of it that he has already made most of the major initiatives he plans.

They were designed to be soothing words, to counter the questioning of whether the President can "cope" with all of his undertakings, and they were no accident. Powell had suggested such an answer should the right question be asked and had drafted some of the language Carter used.

Powell also made it clear in a recent interview that he will devote more time to the courting of influential Washington columnists and commentators, whom he believes set a tone that affects not only general public attitudes but the daily reporting of the President and the administration:

"A good part of the analysis is done by people with no firsthand knowledge of this White House," he said. "They have long experience in Washington, but this is a somewhat different approach that they are not familiar with. It's a job that needs to be done."

The same problems that led to the shift in Powell's role have given rise to suggestions that the entire Carter White House needs to be restructured. There has been speculation that someone - probably political adviser Hamilton Jordan - would become de facto "chief of staff," the better to coordinate all of the President's activities, or that someone like special trade representative Robert S. Strauss would be brought in to gain control of the operation.

But knowledgeable White House aides who are outside the tight inner circle of Georgians around the President discount this speculation and in general defend the way the Carter White House has operated, and apparently will continue to operate.

Jordan is the first to admit that his temperament and his loose and often sloppy habits make him ill-suited to be anything like a chief of staff. He continues to function as something of a crisis manager, throwing himself into whatever issue or problem is currently at the forefront. A few months ago it was the Middle East. Later, it was the Panama Canal treaties. Now it is energy.

"I don't think structure is nearly as important as the people you have," one official said in defense of the existing system. "It has to be a function of the people you have. Carter is clearly comfortable with it."

To bring a Bob Strauss or some other outsider into the operation, this official added, "would be a big mistake. These people [the intimate Carter aides] have worked with each other and the President for years. Their relationships are established and they all feel comfortable. That is no backstabbing or intrigue at the senior level."

Several presidential aides predicted that after Congress adjourns for the year the senior advisers in the White House will attempt to evaluate the staff's performance over the last year. But they speak of this in terms of "fine tuning" rather than a major overhaul of the White House structure.

There have been reports that a recently established executive committee, headed by Vice President Mondale, is studying how to restructure the Carter White House. But a well-placed source said these reports are erroneous and, rather than looking at internal staff problems, the Mondale committee is attempting to gauge the issues and priorities for the second year of the Carter presidency to avoid the appearance of confusion and dissarray.

Over the months, the internal workings of the Carter White House have change subtly. One by one, senior officials stopped attending the daily senior staff meeting. Now they usually send their deputies and the meetings are held only twice a week.

Carter likes to deal with paper, not people, so the number of aides with regular access to him has evolved to just five - Powell and Jordan before everyone else, plus congressional relations chief Frank Moore, domestic policy adviser Stuart Eizenstat and National Security Affairs Adviser Zbigniew Brzezinski the lone non-Georgian among the five.

Because so few people are involved at the top, decisions are held extremely close, a trait of the President's that unquestionably has contributed to his problems in consulting adequately with Congress and others.

"The facile conclusion is that he's like Nixon, but that is wrong," one of Carter's most thoughtful aides said recently. "He does seek all viewpoints and he wants people to argue with him, albeit on paper rather than in person."

This aide said he sees both good and bad in the staff system around the President, which he, too, does not expect will be changed radically.

"The good is that Carter does work hard and he is efficient," he said. "I'm sure he reads more, and more deeply, than any other President. The few people who do deal with him regularly have his confidence and, I'm sure, a willingness to argue with him.

"The bad is that things are not well-corrdinated. Getting a decision means getting the attention of Jody, Hamilton or Stu. That means many things must go to the very top. People on lower levels feel they are not important - there is no sign of it - and that is demoralizing."

The shift in Powell's role is generally applauded by other aides who share the press secretary's belief that Carter's problems are more in perception than substance. But there is also a recognition of the risks involved in turning over a majority of the daily news briefings - which remain the main source of news about the President - to Powell's deputy, Granum.

The 27-year-old Granum is well-liked by reporters, but he clearly is not another Powell. Granum lacks both Powell's long experience with Carter and the press secretary's easy self-confidence in speaking for the President. As a result, Granum's brieflings have often been almost completely uninformative, his remarks smothered in a cloud of caution. And that has already produced grumbles among some White House reporters that could grow worse and eventually sour Carter's still generally good press relations.

"If it is true Jody does so much better a job, it may be that the administration will suffer more than it gains," one aide said.