This paper studies the key technologies in the coordinated operation of power system relay protection and photovoltaic power stations, analyzes the impact of photovoltaic power stations connected to the power system on relay protection, and discusses how to improve. This paper studies the key technologies in the coordinated operation of power system relay protection and photovoltaic power stations, analyzes the impact of photovoltaic power stations connected to the power system on relay protection, and discusses how to improve. This paper studies the key technologies in the coordinated operation of power system relay protection and photovoltaic power stations, analyzes the impact of photovoltaic power stations connected to the power system on relay protection, and discusses how to improve the safety and stability of the. The power system relay protection and safety automatic device is an important automation technology and equipment used to quickly remove the fault and eliminate the abnormal situation when the power system fails and abnormal operation. When the power system fails or endangers its safe operation. ulation is an indispensable tool for studying photovoltaic (PV) systems protection coordination. To efficiently export this electricity to the utility grid, the generated voltage must be stepped up to medium or high voltage levels—such as 11kV, 33kV, 66kV, or 132kV—depending. An Introduction to Protective Relays for Solar-Plus-Storage Systems Electrical relays, protective devices used to switch power on or off for parts of a circuit, have been integrated into circuits for nearly two hundred years.