Eve Queler conducted a concert version of Wagner's mammoth, rarely played opera "Rienzi" at the Kennedy Center yesterday and turned it into one of the exciting operatic events of the season here.

A spectacle about medieval Rome, "Rienzi" turned out to be a real crowd-pleaser with its strong emphasis on the "grand" dimension of "grand opera" in the old-fashioned sense; no wonder it was a favorite in the 19th century. Even with the visual dimension of the drama missing, the opera was a spectacle with its three choruses (one for the citizenry, one for the legions and one for Roman children) and its brass bands placed in three spots around the Concert Hall.

Surely few in the nearly full house knew more than snatches of "Rienzi," but soon the near-capacity crowd was storming and cheering as if it were "Trovatore." The 3 1/2-hour performance was an auspicious Washington debut for Queler's 14-year-old Opera Orchestra of New York.

The opera, Wagner's third, is a saga of love and bloodletting between the citizens and the nobles in 14th-century Rome that resolves its conflicts with the stoning to death of the title character, a Roman tribune, and yet another burning of the Roman Capitol. It is a straight resetting of a Bulwer-Lytton novel-- with none of the dramatic symbolism that makes the mature Wagner seem Wagnerian.

Yesterday the choruses and the orchestra dominated the show. Wagner gives much of his finest music to the choruses. The main one alternately challenges and exalts the leadership of the tribune. The children's chorus marches in from the back of the hall proclaiming Rome's new freedom under the tribune. The chorus of legions marches out through the Concert Hall aisles to take on the nobles in battle.

The citizens' chorus was the Choral Guild of Atlanta, a large and tightly disciplined body that sang with stylistic authority. The legions were the Coast Guard Academy Singing Idlers and the children were Washington's National Children's Choir.

Queler was especially proficient at keeping so many different strands of an operatic fabric together. There was little of the raggedness that would be accepted as normal in most opera houses. The foundation of this excellent ensemble work is Queler's orchestra, one of the best sounding opera orchestras now playing. Her tempos were broad and dignified.

The music for the singers is sometimes tedious declamation (Queler cut some of this, as well as Wagner's curiously inane ballet music). The title character, sung yesterday by tenor William Johns, sings often in the symmetrical phrases typical of early Wagner tenor-writing, a style that breaks into full flower in the famous prayer in the fifth act. Johns had the right kind of voice, but in much of the prayer his pitch was so variable that he had to stretch and bend where the music didn't call for it.

Rienzi's sister, Irene, was sung by April Evans, a last-minute substitute for Elisabeth Payer. She didn't seem to have her voice under control. It didn't open up until it was very high, and then it was loud and edgy.

The most successful singing of the day was from mezzo Julia Hamari in the pants part of Adriano. Fortunately, she has much of the best solo music--a scene in Act 3 that reminds you of some of Weber's finest arias and some music in the last act that foreshadows Senta's music in "The Flying Dutchman."

Queler and her group were a big hit, and should be brought back regularly.