A thunderous ovation from 800 delegates greeted New York City Opera general director Beverly Sills, the 83rd guest of honor to be ushered in to the strains of "Hey, Look Me Over" last night at the Sheraton Washington Hotel. Moments later, with the arrival of an 84th, the B'nai B'rith Women International Biennial Convention was finally open.

The evening included the presentation to Sills of the organization's Perlman Award for Human Advancement for her work with the March of Dimes crusade against birth defects.

"There is no question that I will be remembered first as an opera singer," said Sills at a press conference preceding the dinner. "The title of humanitarian is a heavy load and I am not sure I can carry it."

"We award this at each biennial to a person who deserves it, if there is a person who deserves it," said Anita Perlman, a past president and founder of the award. "We are very happy to be able to honor Beverly Sills for her contribution."

Sills, the mother of two grown, handicapped children, had advice to offer to parents at the press conference: "Don't try to go it alone," she said. "The worse thing is to lock yourself and your children into isolation."

Convention delegates from around the country and from Israel, Ireland and Canada will meet in the next few days to discuss the group's work, centering on women's issues, Israel's security and the plight of Soviet Jewry.

"It used to be our main function was to serve refreshments for the men," said past president and 50-year member Edith Kornblatt. "Now we are striving to be even more powerful and ambitious as a group. We have a lot more work to do."