Abstract: The safety and stability of the power system are the foundation for the safe operation of equipment. Research into enhancing the reliability is of great importance for ensuring the long-term operation of equipment. This paper presents a practical case of ethylene plant shutdown caused by power grid fluctuation, detailing the power outage process and analyzing the causes of the failure from such aspects as primary equipment and protection configuration. The analysis indicates that the primary causes of the outage were the main transformer capacity failing to meet N-1 requirements, unreasonable regional stability control configurations and wiring errors during the instrumentation power supply transformation. Based on this, further analysis was conducted on management weaknesses. Then targeted solutions and control measures were proposed.

Key words: ethylene plant, line fault, insufficient main variable capacity, quick cut device, SIS system power loss, instrument power supply management