BANGKOK, Aug 18 (Reuters) - Thailand on Wednesday reported 312 coronavirus deaths, a record increase for a second day in a row, taking total fatalities to 8,285, health ministry data showed. The Southeast Asian country also reported 20,515 new infections, bringing total cases to 968,957 since the pandemic began last year. Reporting by Chayut Setboonsarng Editing by Ed Davies Our Standards: The Thomson Reuters Trust Principles.