6.5　Oil System

6.5.1　A turbine oil system shall be installed in the hydropower station，while the insulation oil system is not a necessity.The oil system shall have functions of oil storage，oil transportation and oil purification，etc.

6.5.2　The volumes of turbine oil tank and insulation oil tank shall meet the requirements for oil storage，oil replacement during overhaul and oil purification，etc.The volume of turbine oil tank should be 110% of the oil consumption by the unit with the biggest volume.The volume of insulation oil tank should be 110% of the oil consumption by the main transformer with the biggest volume.(https://www.daowen.com)

6.5.3　The oil treatment equipment shall include oil pumps and oil purification devices，and the type，volume and number of pieces of equipment may be finalized according to the oil consumption of the hydropower station.

6.5.4　A centralized oil system should be installed for cascade hydropower stations or a group of hydropower stations.Oil storage，oil treatment and oil purification equipment shall be installed in the centralized oil system.The setup of oil system shall be simplified for the hydropower station with a centralized oil system.