A plane carrying U.S. Sen. Edward M. Kennedy from western Massachusetts to his home on the coast was struck by lightning Saturday and had to be diverted to New Haven, Conn., his spokeswoman said. The eight-seat Cessna Citation 550 plane lost all electrical power, including communications, and the pilot had to fly the plane manually, according to spokeswoman Melissa Wagoner. No one was hurt. The Democrat had just delivered the commencement address at the Massachusetts College of Liberal Arts in North Adams and was on his way to his Cape Cod home when the plane was struck around 4 p.m., she said. The jet landed safely at New Haven at 4:11 p.m., said Federal Aviation Administration spokeswoman Arlene Murray. A report was filed with the agency, which will look into the incident, she said. Kennedy planned to stay in Connecticut overnight because he was scheduled to return to western Massachusetts on Sunday to deliver a commencement address at Springfield College, Wagoner said.