Abstract: In the field of fire safety, electrical fire hazards are prominent and have become a major hidden danger threatening the safety of life and property. Existing research has insufficiently explored the linkage between series fault arcs and the electrical characteristics of upper and lower distribution systems. To address this current situation, guided by the practical needs in the field of fire safety, this paper focuses on low-voltage distribution systems, builds an experimental platform for AC series fault arcs, sets 10 operating conditions with 3 repetitions for each group, and collects electrical signals of fault arcs as well as upper and lower distribution systems. Through preprocessing the experimental data, combined with methods such as waveform analysis, cosine similarity calculation and analysis of variance, an in-depth analysis is conducted on the time-domain characteristics of the electrical properties of fault arcs, upper distribution system and lower distribution system. The research shows that: the fault duration at the arc point is the longest, followed by the upper distribution system, and the lower distribution system has the shortest; the current kurtosis of the fault arc and upper and lower distribution systems all fluctuates between 1.1 and 1.9, generally ranging from 1.5 to 1.8, which is classified as platykurtic; there is a significant difference in voltage kurtosis among the fault arc, upper distribution system and lower distribution system, and the voltage kurtosis of the fault arc is significantly higher than that of the upper and lower distribution systems; the current impulse factor of the lower distribution system is generally higher than that of the upper distribution system, and both are higher than that of the fault arc point, indicating that the transient current impact caused by the fault arc is more significant in the lower system; the voltage impact of the fault arc is significantly higher than that of the upper and lower distribution systems, showing greater volatility and uncertainty, while the voltage of the upper and lower distribution systems is relatively stable. By capturing the differences in electrical parameters between fault arcs and low-voltage distribution systems and integrating these differential characteristics into the electrical fire monitoring system, the identification accuracy and response speed of the system to fault arcs can be improved, which is helpful for optimizing the fault arc detection devices of low-voltage distribution systems and constructing a fire risk prevention and control system for low-voltage AC distribution systems.

Key words: series arc fault, upper distribution system, lower distribution system, fault duration, kurtosis, impulse factors