Research on Arc Characteristics of Live Working in Low-Voltage DC Distribution Network

At present, the characteristics of source -load -storage low-voltage DC in distribution network are becoming increasingly prominent. In order to ensure the reliability of power supply and operation safety, it is urgent to carry out live working in low-voltage DC distribution network. However, due to the complex working environment and narrow working space, short-circuit faults such as accidental contact are prone to occur during the low-voltage DC live working, which can lead to fault arcs. Physical factors such as heat, strong light and noise of short-circuit arc in the low-voltage DC system pose serious hazards to operators and equipment. Based on this, a ±375V (750V) low-voltage DC short-circuit arc simulation test system is built for scenarios of low-voltage DC live working, and the typical physical characteristics of low-voltage DC arc in open and closed environments are explored and the relationship between them and short-circuit current was analyzed, providing a theoretical basis for the effective development of anti-arc measures for personnel. The results show that the arc incident energy, light radiation intensity and sound pressure are positively correlated with the short-circuit current, and the characteristic intensity is higher in the closed environment. With the increase of current, the growth rate of arc incident energy in closed environment is significantly higher than that in open environment. The low-voltage DC arc radiation illuminance is about 5000~20000lux. The sound pressure level is more than 100dB, and the highest can exceed 120dB. Therefore, it is necessary to wear the corresponding level of arc protection to prevent arc damage when performing live work.