Method and apparatus for recording data of solar power generation system

An energy storage system comprising a first processor and a second processor, which are configured to execute at least one program to perform an operation,

• wherein the first processor is further configured to:
• store, in a first manner, first data about a state of at least one apparatus included in a solar power generation system before an event occurs in the at least one apparatus, in a buffer included in a power conversion system (PCS);
• store, in a second manner, second data about a state of the at least one apparatus after the event has occurred, in the buffer, based on detecting the event;
• store the first data and the second data in a persistent storage device included in the PCS and distinguished from the buffer;
• and
• transmit data stored in the persistent storage device to an external device of the PCS.