ANA Holdings Inc., which has canceled more than a dozen Dreamliner flights since last week, found broken turbines on three 787 planes with Rolls-Royce Holdings Plc engines as part of its investigation into the motors of the Boeing Co. planes. The broken turbine parts damaged other sections in the engine when they snapped off, Maho Ito, a spokeswoman at ANA, said by telephone Monday. The first incident happened in February, when one engine was shut down and the plane returned to Singapore, while the most recent happened Aug. 20 on a domestic flight, according to the carrier. The Japanese airline, the world’s biggest operator of 787s, won’t cancel any Dreamliner flights in the first half of September, it said Monday, after last week saying it may have to scrap more than 300 flights with the plane through the end of September as it checks engines on its fleet of 50 of the marquee Boeing jets. Last week, Rolls-Royce said the problem is limited to a small proportion of the ANA fleet and that it is working with the carrier to lessen the impact. The Sankei newspaper reported the damage to the engines Sunday. The issue, ANA’s biggest with the model since a 2013 global grounding of the entire Dreamliner fleet, came to the fore after corrosion was found on the turbine blades that led to an aircraft having to shut down a power plant. Rolls-Royce will start supplying ANA with modified versions of the turbine blades from January and the carrier will replace the current blades in all its planes, ANA said last week.