Abstract: According to the problems in ETS protection of Shenzhen Mawan Power Company 5#-6# plants,the system was redesigned.The original system has been splitted into Turbine ETS system and water pump METS system. The protection system has been optimized,and the original size of the ETS system for protection cross, inconvenience of the maintenance of insulation has been solved. At the same time, the latest DCS system was adopted to solve the problem of hardware aging and spare parts procurement, which greatly improved the safety performance of the steam turbine protection system.