春晨 JBHF电机引接线 电机专用连接线

江苏春晨电缆有限公司生产JBHF电机引接线，JBHF电机引接线，

差动保护

differential protection

差动保护是根据被保护区域内的电流变化差额而动作的。它广泛用来保护大容量的电力变压器、变电所母线、高压电动机等。如右图所示是电力变压器的差动保护原理图。

Differential protection operates according to the difference of current variation in the protected area. It is widely used to protect large-capacity power transformers, substation buses, high-voltage motors and so on. The principle diagram of differential protection for power transformer is shown in the right figure.

差动保护原理图

Schematic diagram of differential protection

电流互感器TA1和TA2之间的区域就是差动保护区，当保护区内发生短路故障时，即变压器内部（如dl点），电流继电器KA中将产生较大的启动电流使保护装置动作，而当保护区外短路时，即变压器外部如（d2点），电流继电器中只流过一较小的不平稳电流，保护装置不会动作。

The area between the current transformer TA1 and TA2 is the differential protection area. When short-circuit fault occurs in the protection area, that is, the transformer interior (such as DL point), the current relay KA will generate larger starting current to make the protection device operate. When the protection area is short-circuit outside, that is, the transformer exterior (d2 point), only one of the current relays. The protection device will not operate when a small unstable current is flowing.

单相接地保护

Single-phase Grounding Protection