降低链条；其他断路器必须能够
承受与通道相关的热应力和电动应力
故意延时的故障电流。选择性断路器，
通常为空气式，必须用于各种级别，以确保足够的
高短时耐受电流；
•短路电流引起的干扰持续时间
未受故障影响的区域内的电源电压可能会导致电子和机电设备出现问题（电压低于
电磁释放值）；
•歧视级别的数量受到
网络可以稳定运行。
以下示例显示了获得的时间判别的典型应用
通过不同设置不同保护装置的跳闸时间。
电子版本：
E4S 4000 PR121-LSI In4000
E3N 2500 PR121-LSI In2500
T7H 1600 PR332-LI In1600
L（长延迟）
设置：0.93
曲线：36秒
设置：1
曲线：24秒
设置：1
曲线：18s
S（短延迟）
设置：10
曲线：0.5s
设置：10
曲线：0.2s
I（IST）
关
关
设置：10

cally lower down the chain; the other circuit-breakers have to be capable of withstanding the thermal and electro-dynamic stresses related to the passage of the fault current for the intentional time delay. Selective circuit-breakers, often air type, have to be used for the various levels to guarantee a sufficiently high short-time withstand current; • the duration of the disturbance induced by the short-circuit current on the power supply voltages in the zones unaffected by the fault can cause problems with electronic and electro-mechanical devices (voltage below the electromagnetic releasing value); • the number of discrimination levels is limited by the maximum time that the network can stand without loss of stability. The following example shows a typical application of time discrimination obtained by setting differently the tripping times of the different protection devices. Electronic release: E4S 4000 PR121-LSI In4000 E3N 2500 PR121-LSI In2500 T7H 1600 PR332-LI In1600 L (Long delay) Setting: 0.93 Curve: 36s Setting: 1 Curve: 24s Setting: 1 Curve: 18s S (Short delay) Setting: 10 Curve: 0.5s Setting: 10 Curve: 0.2s I (IST) Off Off Setting: 10