路灯线路各电气安全防护系统的特点

Features and Characteristics of Different Protective Systems for Road Lighting

接零保护系统故障回路的阻抗较小，能及时切断故障回路，是接零保护系统电气安全防护的常用方法而短路点电压与接地装置、土壤电阻率和系统情况有关，常规的接地电阻值不能确保任何情况的短路点电压都低于50伏。路灯线路用接地保护系统，容易使短路点电压低于50伏，但难以自动切断故障回路。文中用七个例子说明切断故障的时间和短路点的电压。

The zero sequence protection system functions mainly for the timely cutting off fault circuits since the impedance of the latter is very low. However, since the short circuit voltage relates to the earthing devices, the soil impedance, and the system configuration, the normal earthing resistance will not ensure the short circuit voltage will be always below 50 volts under all circumstances. The earthing protection system will be easier to realize that but it will be difficult to cut off the fault circuits automatically. This article uses 7 scenarios ti describe the fault cuting off timing and short circuit volatage.