Roger Bennett of Gar-Field High became the second high school triple jumper to reach 50 feet in Penn Relays history today when he won the invitational event at 50 feet 1/2 inch.

The senior from Woodbridge, Va., who is headed for George Mason, leaped 50 feet in the trials, then added a half-inch on his final attempt. Only New Yorker Sanya Owolabi, in 1977 and 1978, had topped 50 here before.

Bennett was later named the Penn Relays' outstanding high school field events performer, the first time a Washington-area athlete has been selected for that honor since the awards began in 1958.

In the relays, T.C. Williams of Alexandria, Va., placed fourth in the championship 4x400-meter race in 3:15.27, with H.D. Woodson of Washington fifth in 3:15.63.

West Philadelphia, on the strength of Alan Laws' 46.4 anchor, became that city's first school to win the event since 1941, clocking 3:12.96. Camperdown of Jamaica wound up second with another Jamaican team, Calabar, third.

Camperdown was forced to insert a substitute after leadoff man Michael Warren broke his left leg in a fall at the start of his morning heat. While an ambulance drove onto the track to remove Warren, Andrew Smith took Warren's jersey and ran despite an injured ankle.

T.C. Williams' quartet of Cedric Matterson, Quinton Smith, Thomas Hairston and Gregory Wright had the best qualifying time (3:17.7) among Washington- area schools.

Woodson's Adam Hansford, John Curtis, Gable Barmer and Wayne Sescoe posted 3:18.3 to advance to the final.

Among the nonqualifiers, good times were posted by Ballou, 3:21.8; Central, 3:22.8; Suitland, 3:23.2; Herndon, 3:25.1; Theodore Roosevelt, 3:25.5; Meade, 3:26.2, and Episcopal, 3:27.2.

Camperdown captured the 4x100 championship in 41.41, giving Jamaica its fifth straight title in that event. T.C. Williams placed fifth in a consolation race in 42.83.

Willingboro, N.J., defeated Camperdown in the 4x800 championship, clocking 7:40.98.

Woodbridge High had the best time, 7:59.2, among Washington-area schools, none of which qualified for the final. Kennedy of Silver Spring was timed in 8:04.2 and Suitland in 8:05.4.