Joseph P. Yeldell, whose troubled a administration of the D.C. Department of Human Resources stirred one of the biggest political commotions in recent city history, has quietly assumed broad powers and a key political role in Mayor Walter E. Washington's administration.

Yesterday, Yeldell was sitting in the mayor's chair for the second time in less than a month, presiding over a meeting of the mayor's cabinet in Washington's absence.

He has been designated the mayor's liaison with citizen's groups, some of whom are outraged and insulted by his involvement with their concerns.

He directs the city's effort to ensure that more than $35 million in city contracts will be awarded to minority firms, and he is in charge of the vital community relations program aimed at bolstering the mayor's image and, some say, laying the groundwork for a possible Washington re-election campaign in 1978.

Yeldell does all of this from the same spacious, well appointed office on the fourth floor of the District Building from which he commanded DHR for five years. Meanwhile, his successor, acting DHR director Albert P. Russo, occupies the same cramped quarters down the hall that Russo was in when he was Yeldell's deputy.

Russo's aides and deputy have to share office space until Yeldell moves, and sometimes even hold meetings in the kitchen outside Yeldell's office, according to some employees in the DBR executive suite. Russo said he expects Yeldell to be out of the DHR director's office by the end of this month.

It was only seven months ago that Yeldell was fighting to maintain his image and his job in the Washington administration amidst allegations of broad abuse of power and conflict of interest in his stewardship of the city's largest agency.

Yeldell was suspended by the mayor for four months pending investigations of the accusations. In March he was removed as DHR director and made a general assistant to the mayor.

In the three months since then, Yeldell has gradually re-established his importance in the mayor's administration in a role that some observers believe rivals his standing before the controversy began.

Yeldell, complaining that he is constantly misrepresented by the news media, refuses to talk for the record with reporters about his new duties.

Sam Eastman, the mayor's press secretary, said he does not know the full extent of Yeldell's duties. Yeldell has a number of assignments, some of which the mayor assigned him and some of which he initiated on his own," Eastman said.

Among the other duties, Yeldell is the mayor's liaison to the city's Office on Aging, to the dismay of some senior citizen groups who fought sucessfully two years ago to have the agency removed from Yeldell's control in DHR, because they felt it was improperly managed.

"I am frankly puzzled and concerned about Yeldell's involvement in the aging office, Sister Jane Kane, of Our Lady of Victory Community Church, told a group meeting Thursday to discuss the Office on Aging. "Everybody knows Yeldell's record on DHR."

Last month Yeldell attempted to act as a stand-in for the mayor at a meeting of advisory neighbourhood commissioner. The ANC members walked out in protest.

It was like sending the devil to Jimmy Carter's church," ANC member Carol Gidley said afterward.

Donald Shannon, one of the participants, said the ANC group had been trying to meet with the mayor since last July.

They were told shortly before the scheduled May 18 meeting that the mayor was sick and had been sick for a month, Shannon said.

Shannon said Yeldell "was going to be a very smart fellow and try to calm us down . . . I resented it."

Yedell apparently has no involvement in the day-to-day operation of DHR, although four of the agency's employees have been detailed to work for him in his new capacity.

Albert P. Russo, Yeldell's former deputy, and now acting DHR director, has repeatedly said he has to work long hours, trying to correct the department's many problems, most of which occurred during Yeldell's five-year tenure.

When Yeldell was director of DHR D.C. General Hospital lost, its accreditation. DHR has also been ordered by a federal judge to raise the hospital's standard of care of an acceptable level.

Also during Yeldell's tenure, DHR lost millions of dollars in federal grants for health programs asa result of what U.S. agencies said were problems in management of the programs.

Last year, Yeldell and the agency also came under fire from congressional committees and federal agencies for the faulty operation of Forest Haven, the city's home for 1,000 mentally retarded District residents.

Yeldell was removed as DHR director after newspaper articles reported that he had improperly used his position to get friends and relatives jobs in city governmnent and that he had used DHR's leasing authority to leas buildings at unusually high costs.

Although Yeldell was cleared of any personal wrongdoing in investigations by the D.C. auditor and the mayor's Office of Municipal Audiit and Inspections, the U.S. Attorney's Office here is still investigation Yeldell's leasing practices.

The mayor removed Yeldell as DHR director despite the clearance, however, saying that the controversy surrounding Yeldell's stweardship had become a burden to the effective operations of the massive city agency.

At the cabinet meeting chaired yesterday by Yeldell and attended by most of the city's agency heads, topics discussed included the minority contracting program, a rescheduled meeting with ANC representatives and a forum next week at which cabinet members are to field questions from community groups representatives.

The mayor himself, who was absent from yesterday's meeting, has chaired only two such meetings since Yeldell was removed from DHR. A few cabinet members remarked privately afterward that the meeting run by Yeldell had moved more smoothly than those handled by the mayor.