PLCs are high-precision electronic devices that rely on stable low-voltage logic circuits to accurately execute preset commands and process real-time operational data. Various common power quality issues widely exist in industrial power grids, including voltage sags, transient surges, harmonic distortion and high-frequency electrical noise, all of which pose direct and persistent threats to PLC normal operation. Slight and instantaneous voltage fluctuations can easily trigger accidental PLC resets or program suspension. Distorted power waveforms will cause deviation in sensor signal acquisition, leading to PLC misjudgment of operating parameters. Meanwhile, high-frequency electrical noise generated by high-power industrial equipment will seriously interfere with real-time data transmission and signal interaction between PLCs and peripheral actuators and sensors.

These subtle and irregular power anomalies bring tangible and diverse industrial losses to factory production. They often lead to sudden interruption of continuous production batches, unqualified product output due to inaccurate control, and frequent false fault alarms of the entire automation system. Different from obvious mechanical failures that are easy to detect and repair, PLC faults induced by poor power quality are mostly intermittent and random. Such hidden faults are difficult to locate and troubleshoot, requiring massive time and labor for daily inspection and maintenance, which greatly increases the overall operating costs of industrial production.