Practical case studies demonstrate its effectiveness, while key challenges such as system stability, information security, and cross-regional coordination are discussed. Finally, the paper examines future trends and potential advancements in relay protection technology. able sources such as wind and solar. These clean energy sources, connected through inverters and flexible transmission systems, are transforming traditional grids based on synchronous generators into more flexibl cant challenges to system stability. Nowhere is that clearer than in the challenge to. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. The selection and applications of. Relay protection technology plays a vital role in fault detection, isolation, and recovery, evolving with intelligent algorithms, digital equipment, and automated coordination to enhance grid reliability. This can allow for better power transfer capabilities Due to the cost of power transformers, and the cost of. The global energy transition is ushering in a new era of power electronic-dominated grids (PEDGs), to complement the increase in the widespread integration of renewable sources like wind and solar.