Two firms headed by Robert H. Carter III, a Chicago businessman who has been subpoenaed before a federal grand jury here investigating D.C. Deputy Mayor Alphonse G. Hill, were awarded three contracts worth several hundred thousand dollars from agencies under Hill's control, city officials said yesterday.

The grand jury has been investigating Hill's role in the awarding of city contracts to an accounting firm headed by James Hill Jr., a longtime friend of the deputy mayor.

James Hill and Carter share an apartment in Washington and James Hill has done accounting work for Carter.

Carter said federal prosecutors have summoned him to appear before the grand jury to discuss his contracts with the District.

In addition to awarding a contract to one of Carter's firms to handle payroll deductions for city employes, the city awarded a contract to another of Carter's firms in 1983 to study the city's insurance programs, according to District officials.

That contract originally was for $69,000 but was expanded three times without new bids, a city official said. The final cost totaled $198,000, according to the official.

In January a Carter firm, Group Insurance Administration Inc., won a third contract, to handle dental and vision services for the city's 16,000 nonunion employes. The company was the only one to submit a formal proposal to the city, according to city officials.

Both Carter's firms and James Hill's firm, Hill, Taylor & Co., have their home offices in Chicago, where Alphonse Hill worked before joining the administration of Mayor Marion Barry in 1979.

Carter has declined to comment on details of his city contracts.

Alphonse Hill, who declined to comment yesterday, has previously denied any wrongdoing. James Hill has called the federal investigation a "fishing expedition."

City officials said that many firms were interested in bidding for the dental and vision contract. However, the number of firms eligible to bid was limited when Alphonse Hill decided to restrict bidding to minority-controlled companies, according to a city official.

Edwin G. Ross, an aide to the deputy mayor, said that the city advertised the contract in the newspapers, and four firms picked up specification lists. But Ross said the formal proposal by Carter's firm, Group Insurance Administration, was the only one received by the District government.

"There aren't too many minority businesses that can do that kind of work," Ross said. Ross, who said he wrote the specifications, said the selection process was "clean and straight."

Alphonse Hill signed the contract with the Carter firm on Jan. 6, and a city purchasing official signed it on Jan. 10, according to a city official.

An insurance industry official, who asked not to be identified, said yesterday that in late December Carter was seeking assistance in lining up doctors to provide the services required by the city. The official said he thought it was unusual for Carter to be seeking the large number of doctors needed at such a late date.

A city official, who also asked not to be identified, said that part of the problem was that the legislation approving the new medical benefits was passed by the City Council in October, which left little time to get the program under way.